Cooking with a Conscience

The Naked Scientists head to dinner with a brand new kind of oven!
16 April 2019
Presented by Chris Smith, Katie Haylor
Production by Katie Haylor.


Chefs at work in a professional kitchen


This week a Naked Scientists exclusive: we're putting a brand new type of oven to the test - can it really, as the inventors claim - roast a raw chicken in 35 minutes? Plus, the brave scientists who've attached cameras to Great White Sharks, and what does a black hole really look like?

In this episode

Event Horizon Telescope (EHT) researchers unveiled the first direct visual evidence of the supermassive black hole in the centre of galaxy Messier 87.

00:53 - First images of a black hole

Scientists make history with the first black hole pictures!

First images of a black hole
with Carolin Crawford, University of Cambridge

This week, scientists have just announced the first images of a black hole. Chris Smith was joined in studio by astronomer Carolin Crawford from the University of Cambridge, to explain how this was done, and what it means...

Carolin - Well, just first to stress, it’s not actually an image of a black hole. It’s the closest we can get, but you are seeing effectively the silhouette of the event horizon around a black hole. So you’re more or less sitting in the shadow it casts towards us. So that hole that you see, I mean if you look at the image it’s this beautiful bright annulus with a dark circle in the middle - that’s not a black hole that’s the shadow of the event horizon.

Chris - It looks like a bit of a bagel in the sky, doesn’t it? It’s a long way away though isn’t it?

Carolin - It’s 55 million light years away and it sits right at the centre of a colossal giant elliptical galaxy called M87. And we’ve already weighed the mass of the black hole, it’s six and a half billion times the mass of our Sun.

Chris - How do you know that?

Carolin - We know that because a black hole you can’t see it, but you can measure its gravitational effect on matter around it, in this case it’s ionised gas, and stars in the vicinity you look at how they’re moving, you can work out what gravity they’re responding to, you can weigh the black hole. One thing that has come out of this that’s nice is those estimates match very nicely the size of the event horizon we see here, so there’s a consistent story about the mass within this black hole.

Chris - How were the images assembled or prepared?

Carolin - The images were taken with something called the Event Horizon Telescope which is where you mock up a radio dish the size of the Earth by linking together eight widely separated radio telescopes. The reason you do that is that if you increase the effective diameter of your telescope you get very good, what we call angular resolution, that’s the ability to see details. And if you increase the size of your radio dish to that of the Earth well, you can get a resolution that you could detect a grapefruit on the surface of the moon and that is ideally matched to the event horizon around the supermassive black hole M87 and also the supermassive black hole at the centre of our galaxy called Sagittarius A*.

Chris - Yes, I was interested that they chose to report on the bigger one was a lot further away, though, than the one in our own galaxy. Do you think they’re saving the best till last? Do you think they’ve got some big reveal up their sleeves?

Carolin - Well, the nearer one - nearer, I mean it’s still 26,000 light years away. The thing about Sagittarius A*, it's 4 million times the mass of our Sun, so it’s a thousand times smaller, it’s a thousand times nearer but it’s also much more variable. Changes in brightness are on a much faster timescale so actually correlating all the data from all these eight different telescopes is a lot harder work. So there will be a big reveal, they’re just being more careful and they’re taking longer to do it.

Chris - And what do you think they will do next then because now we can image black holes, will they just turn their devices on as many black holes as possible?

Carolin - Well first of all, there are improvements. I mean, obviously, we’re going to look at more supermassive black holes - different ones, but you can improve the algorithms to try and sharpen the images. We can observe at other wavelengths and try and improve the angular resolution, the detail we can see and see fine structure around the black hole. And if we really wanted to be adventurous we could perhaps increase, in the long future, the diameter of this potential radio telescope, put a radio dish on the Moon. Again, get to far more detail and perhaps see changes in real time of how this material is accreting onto the black hole, almost get a movie of this accretion as it happens.

Chris - We’ve had a whole slew of questions on our forum: This persons says: how many kinds of black hole are there? Do they come in different flavours?

Carolin - Oh yes, there are definitely different flavours of black holes. There are two kinds that we regularly observe; you have the ones that, we call them stellar sized, but in fact they’re probably ten times the mass of our Sun and they’ll go from about ten solar masses up to about 60 solar masses, and they’re the ones that you find like in the spiral arms of galaxies, they come from the death of stars.

But then you get the behemoths that live at the centres of galaxies, and these are what we call the supermassive black holes. And these are the ones that can be millions, if not billions times the mass of our Sun.

Those are the astrophysical black holes that we actually observe. There are predictions that there could be something called primordial black holes that maybe formed either during or just after the Big Bang. But we don’t observe those yet and so that’s more speculation.

Chris - That question came from Mad Atheist on our forum who also says how many of these black holes involve a singularity? Do they all have one; is that an obligatory thing with a black hole?

Carolin - Yeah, that’s what defines it as being a black hole. Singularities where you have something that goes to infinite value and we’re talking about basically infinite density. So, by definition, all black holes are the singularity

Chris - And what happens, he is asking, when you get to the event horizon to the speed of light? Does light inside a black hole change speed or is it still running at the speed of light?

Carolin - Who knows! Once things go over the event horizon our physics break down. I couldn’t speculate.

Chris - Geordie F wonders, is there any way we can know anything related to the mass distribution inside the black hole i.e. over the event horizon? This goes back to the point the person was asking about knowing about the speed of light or not inside the black hole. I guess the answer’s going to be no.

Carolin - The answer’s no. The event horizon is literally the horizon beyond which we can see no event and we can do the thought experiments, but it’s completely locked away. Anything that’s going on beyond that boundary is completely locked away to us at the minute. There’s no way we can work it efficiently mathematically or observationally.

Chris - Were you excited when you saw the initial papers come out?

Carolin - Very excited. The data were taken two years ago so everybody’s just been on tenterhooks for this image that we knew that was coming. So it’s very satisfying.

Vaccine injection

06:56 - Immune systems tackling cancer

Could we make our immune systems destroy cancer?

Immune systems tackling cancer
with Joshua Brodie, Mount Sinai School of Medicine

One in three of us will develop cancer at some point in our lives. And, thankfully, in recent years treatments have improved dramatically; in fact we can now hold many tumour types in check, for considerable periods of time. But the therapies that do this are extremely costly, and they can have significant side effects. Which is why researchers are particularly keen to make better use of a free, natural resource available to all of us: our own immune systems. The immune system doesn't usually target cancers because it recognises the cells as part of the body. But a new study in Nature Medicine has found that with the right signals injected - like a vaccine - into a tumour, it’s possible to persuade immune cells otherwise. Chris Smith spoke to Joshua Brodie from the Mount Sinai School of Medicine in New York...

Joshua - We refer to it as in-situ vaccination. All it really means is we are making the vaccine at the site of the tumour by injecting immune stimulants directly into the tumour to try to trick the body into thinking that this cancer is like an infection, so they can learn the lesson at that tumour site and then travel throughout the body to eliminate tumour cells wherever these immune system cells can find them.

Chris - And what do you put in? When you say you’re put in immune stimulants, what are they and what are they actually stimulating?

Joshua - Sure. It’s a great question and it requires one key bit of background which is the 2011 Nobel Prize was awarded for this crucial immune cell called the dendritic cell. If we think of most of the immune cells, we call them T cells, as soldiers of the immune army, the dendritic cell is the general of that immune army and it instructs the soldiers who to attack and eliminate.

The first immune stimulant that we inject into the tumour is something called Flt-3L, and we administer Flt-3L directly into a tumour. We bring many dendritic cells to that tumour so they can start to see what the tumour features - we call them antigens - are that we want to recognise.

Chris - So that's a bit like your taking a war analogy, sounding the bugle at the site of the tumour so that these dendritic cells which have the ability to marshal immune effectors, these T cells, they’ll come in but they've got to have something to work with, haven't they, so how do you get the dendritic cells to then pay attention to the tumour cells?

Joshua  - Sure. So the second ingredient is something called low-dose radiotherapy. It's basically just a very small dose of radiation to that tumour which kills a few tumour cells, releases their antigens, and those dendritic cells then gobble up the antigens so they will be able to present them to the immune soldiers, to the T cells. It will go even beyond a bugle, it will be a bugle plus a PA system.

And then ingredient three is another immune stimulant that we inject directly into the tumour and it's called a Tlr, a Toll-like receptor, agonist, and it activates those dendritic cells to convey that these tumour antigens are like an infection, these are something that we should attack and those dendritic cells then instruct the rest of the immune soldiers on what to recognise and what to eliminate throughout the body.

Chris - What's the evidence this works though?

Joshua - We in this paper describe the in-situ vaccine in two very different contexts. We describe in the lab, using animal models, where we really prove exactly how it is working, and then we brought it into an early phase clinical trial for patients with advanced stage non-Hodgkin's lymphomas. And we've had some patients with partial and complete remissions of their cancer, and those remissions have been going on for months or years for some of these patients.

Chris - Now so far, you've talked to me about attacking non-Hodgkin's lymphoma; these are cancers of some of the white blood cells. Could this same strategy though be used for other types of cancer; for instance melanoma - very common cancer of the skin, could you treat that with this?

Joshua - We believe it would work for most types of cancer, if not every type. In the lab we actually have studied melanoma where we showed pretty similar and very good results and really our next direction is to bring this into a clinical trial for patients. In fact, that follow-up trial is already just opened this past month and that trial will treat patients with lymphoma or breast cancer or head and neck cancer.

Chris - Sounds terrific... but. And there's always a 'but' with these things isn't there? One has to be cautious because is there not a risk, given that there will be some healthy normal cells and antigens in these tumours, that the immune system could begin to respond to perfectly normal signals on normal cells, as well as the bad markers signalling cancer cells and you might end up with an autoimmune disease where the immune system turns on itself?

Joshua - Chris, absolutely. In fact, that's the primary concern with all these types of immune therapies. As we push the immune system, we might possibly push it too hard and it could attack both cancer and some healthy cells as well. What you say is exactly correct; in a very small percentage of patients that could happen with some of these immuno-therapies. With the vaccine approach, we think there is at least some more specificity. But you're right, there could possibly still be healthy cell antigens within that tumour. We can only say so far that we've done this in a number of patients and we have not seen that so far. But you're right, we definitely have to be wary of side-effects as we push ahead, certainly.

A picture of the Earth from the ISS space station

13:50 - Identical twins in space

What happens to identical twins when one of them goes to space?

Identical twins in space
with Lindsay Rizzardi, Johns Hopkins University

The results of an ambitious study to explore how the human body is affected by flight has just been announced. Twelve teams from various universities across America have been looking at cells, genetics and general physiology. Lindsay Rizzardi, from Johns Hopkins University, spoke to Izzie Clarke about these out-of-this-world results...

Izzie - Fancy a trip to space? The years of physical and mental training, the waiting, will you be chosen for a mission? Then you get strapped into a rocket, blasted off into space and live on the International Space Station for months. Most of the time, astronauts are up on the ISS for up to 6 months, but in March 2015 an American astronaut called Scott Kelly was one of two people selected for a year-long mission to space, and there was something special about Scott that grabbed scientists’ attention...

Lindsay - The idea for the study came from Scott Kelly himself. He knew he was scheduled to go on the one-year mission and approached NASA and was like hey, you know I've got a twin brother that's going to be here and we’ve both been astronauts, would it be cool to study us, since we’re twins and we have the same genetic sequence? And NASA said yes, that would be fantastic.

Izzie - That's Lindsay Rizzardi. She was a part of a team at the Johns Hopkins University that looked into the genetic information of Scott and his twin Mark. The key factor being that, as an identical twin, their DNA is the same, and this was the beginning of a mammoth study to explore the impacts on the human body of life in space compared to that back on Earth. Lindsay and her supervisor, Andrew Feinberg, were interested in something called methylation, which is a process that goes on in your DNA.

Lindsay - What DNA methylation actually is is it’s a chemical tag that gets deposited on your DNA. And it doesn't change your DNA as far as changing the sequence or anything like that, but what it does do is it can regulate gene expression and how they are turned ‘on’ and ‘off’.

Izzie - Now, say your genetic code is a cookbook. If you take one single instruction -  that's a gene and that's akin to a single recipe. Now these methylation markers are like putting a mark on that recipe to say "reduce your portion size". So if there are a lot of these methylation markers on a recipe i.e. your gene, it essentially reduces the amount it's making and ultimately stops a gene from doing its job, otherwise known as being 'turned off'.

Lindsay - So, for instance, if you have a lot of these modifications near the beginning of a gene it typically results in that gene being turned off. If there's not much methylation around genes tend to be turned on or expressed. And so what we hypothesised was that we would see big changes in Scott during his time in space that we wouldn't see in Mark.

Izzie - But that's not exactly what they found. In fact, Lindsay and the team found no long-lasting major differences between Scott and Mark's genetic code.

Lindsay - Mark actually had more variation globally in his DNA methylation levels than Scott did. Now we were surprised by this at first, but then we started thinking harder about it and it's like well, of course, Scott is in an isolated environment on the space station for a whole year, his diet is limited, his environment’s not changing much; whereas Mark on Earth could travel, he could eat whatever he wanted. Given that, it's not as surprising that we didn't see as much variation in Scott. Now what is interesting is that we saw genes that were involved in inflammation and in stress response having altered methylation, and we didn't see changes of those same genes in Mark.

Izzie - But how can you compare two people needing fresh blood samples when one of them is orbiting 400 km above you?

Lindsay - It was actually logistical nightmare. What we had to do was coordinate sample collections with scheduled visits to the space station by the Soyuz. So whenever they would get a resupply, Scott or one of his crewmates would have to draw his blood and put it right on the rocket to come back to Kazakhstan, and then in Kazakhstan there’d be a plane waiting to take it Houston, and then in Houston it would get on a truck to the lab. And somebody would have to be at the lab, whether that be noon or 3 o'clock in the morning waiting on the sample so they could separate those cell populations that we needed, freeze them down and ship them out to the labs. So is quite a feat, and I think one of the great accomplishments of this study is actually getting all of that logistics worked out so that this is how we can do things in future.

Izzie - Especially in a future that may involve human space flights to Mars...

Lindsay - Definitely. I mean, I think if you're going to plan space missions to Mars then you need to be prepared. Any information that we gather on the potential risks of this longer duration spaceflight is going to be beneficial. And you're going to have to take it into account when you plan longer longer duration missions because it’s interesting too, this was the first time an astronaut had been in space for over a year, at least for us. We actually saw a lot of our changes happening in that last six months of flight, and so it really is the longer duration that we're starting to see effects.

A white shark with attached camera tag

Following great white sharks
with Oliver Jewell, Murdoch University

Great white sharks are iconic animals, but they're also ones that we know very little about. And they're on the watch list of threatened species that conservationists internationally are trying to save, despite the misleading portrayal of the animals in some films. But, for conservation efforts to be successful, we need to learn as much as we can about where these animals go, how they hunt, and what sorts of environments they actively seek out or avoid. Now we're a step closer to doing that. With cameras that temporarily latch onto the dorsal fin, researchers have got their first glimpses of the Great White's underwater world. Chris Smith spoke to Oliver Jewell from Murdoch University....

Oliver - So what we've effectively done is put camera tags on white sharks in one of the first ever studies to do that, and it's part of a longer term study where we've used lots of different techniques to study these animals and each filling in a new part of the picture, but this one is really quite a big chunk of the puzzle which we just didn't see before.

Chris - One always gets a bit nervous when people talk about big chunks of things and great white sharks but where were you studying them?

Oliver - So this was all done in South Africa off Hans Bay which is in the Western Cape. Just offshore there's a really interesting island system and it's called Dyer Island and the seal colony is actually on Gyser Rock where there is 50 to 60,000 Cape Fur seals depending on the time of year and it attracts what was the largest population of great white shark anywhere in the world.

Chris - So how did you actually get cameras onto these things because these are big animals for a start aren’t they?

Oliver - Yes.

Chris - And they're not known for being particularly friendly necessarily, so how did you solve both of these problems?

Oliver - I worked for many years on a cage diving vessel and we kinda use the same technique. You put a bit of fish in the water and you use either a seal shaped decoy or a piece of bait and the shark swims up towards it. While the shark’s looking at this piece of bait or decoy, someone will lean over the side of the boat with a pole and a clamp and clamp these tags to the fin of the shark.

Chris - When you say “clamp” because one of the worries that marine biologists and the wider scientific community have is that we don't injure these animals when we tag them, so how do you satisfy the necessity to study but not harm?

Oliver- Well, with these clamps they're corrodible. So they'll fit onto the dorsal fin, but after a certain amount of time the tag pops off and comes to the surface so we can retrieve it and then the clamp falls apart and falls off the fin. So we don't want to leave any part on the animal beyond a week or so.

Chris - And as the animal's swimming so you've got video capture of where it's going and what it's seeing is that being stored on the camera device so that when it does resurface and you retrieve it that's when you get the data back?

Oliver - Yeah, exactly. We don't get anything if we don't get the tag back. So it's always a big risk when you put this expensive piece of equipment out in the ocean and then you have to hope that it films something good. It's also got a high-resolution motion sensor inside that's a bit like Fitbit and so every second there's 40 pieces of information going in on the heading of the animal in three-dimensions, the depth it’s swimming at, as well as the video. And then when it comes to the surface we've got either a satellite tag or a VHF tag on it so we can hopefully track it down, and if not we write our email address and hope that somebody emails us.

Chris - What was it like when you look at the footage and you are able to pursue these animals on their day-to-day business - any surprises? What did you see?

Oliver - Oh well I mean, for the most part the animals are just swimming. We've got to get good visibility too. Often it's really murky and the shark is just sitting there swimming along and you don't see anything exciting. But just every so often, something will catch shark's eye and it will start moving and we had one where the water was really clear and the shark was kicking up towards the surface and I was trying to see ‘What's it going for? It must be going for a seal or something’, and then it gradually slows and you look up and you see the surface, and you see above the surface there's a seagull flying and this shark just tracks it. For whatever reason this shark must have had a look at the seagull and decided I’m going to go and swim up and see what that is.

Chris - So in some respects it's not just telling us about where the animals go, it can also give us useful information about their behaviour and not just how they react to stimuli underwater either?

Oliver - Exactly that. I mean we can see different portions of time that these animals might be spending doing one behaviour versus another. We can see how much they move up and down the water column and how many times they beat their tail per minute. So we can see a lot more of these animal's day-to-day lives than we would be able to with a traditional tag that might give you a position every week or so.

Chris - And what are you going to do next?

Oliver - So what we're doing at the moment is building quite a large dataset where we're putting these tags or similar on white sharks in South Africa, in California, and possibly in other places as well, and then we really will be able to make a global comparison in their foraging patterns. And we’ll be able to look at things like how they change over time as they get larger and their prey preference will change for instance. We'll be able to track how they do that in terms of activity, in terms of their foraging aggregations in many places across the world.

this is a picture of a chopping board full of vegetables

The scientist and restauranteurs
with Mark Williamson, Alex Rushmer and Lawrence Butler

It’s not every day you get the chance to interview professional chefs in a brand new restaurant. And what’s more, a restaurant which has installed an experimental oven which the creators claim can revolutionise cooking. So will it work? Katie Haylor and Chris Smith set its inventor the grand challenge of roasting a raw chicken in just 35 mins. Here's Mark Williamson - the scientist behind the oven and Alex Rushmer and Lawrence Butler - the two chefs putting sustainability at the heart of their new venture…

Lawrence - Hello. My name is Lawrence Butler.

Alex - Hello. My name is Alex Rushmer and we're at Vanderlyle in Cambridge. Vanderlyle is a brand new restaurant opened by myself and Lawrence and we are a primarily vegetable focused, sustainable restaurant in the centre of Cambridge on Mill Road.

Chris - And standing next to Alex is...

Mark - I'm Mark Williamson. I teach chemical engineering at the University in Cambridge and I'm also the founder of Cambridge Oven Innovation. It's a spin out company from the University and we are developing a brand new exciting domestic oven.

Chris - Now I know that fellows at the University of Cambridge are fond of fine dining and fine cuisine, perhaps that's why you're in this fine restaurant, but why are you really here?

Mark - Because we’re doing some exciting food trials with Alex and Lawrence, discovering new ways to cook food using this new technology. We have an oven which cooks food in fundamentally different ways to conventional ovens and it uses substantially less energy.

Chris - Now Alex, you run a serious business, serious venture, you’ve been on MasterChef, what did you think when he came to you and said I’ve got an oven which is going to reinvent the way we do cooking?

Alex - Initially, a little bit sceptical I suppose, but that was changed pretty quickly once we saw the oven in action. It's very rare that you get to see something at such an early stage of development and something that can so fundamentally change the way that we do things in the kitchen, so it was super exciting.

Lawrence - The immediate results that we saw impressed us so much that we couldn't help but be involved.

Chris - So you've actually installed one here and are you gonna knock out your daytime nosh on this to see really how it performs? Is that the idea, you're sort of doing a clinical trial for an oven?

Lawrence - We are going to be doing a lot of recipe testing for the oven so that we can eventually have a database of things that we have figured out exactly what the best way to cook using it is so that we can have that for the end user as well as a resource really.

Alex - Chefs love their toys, they love their gadgets, and they love anything that makes their lives easier, makes the processes quicker. Given our fairly fundamental approach and focus on sustainability, anything that uses less energy is always going to be a bonus for us.

Chris - Have you given these guys some shares?

Mark - We have indeed yes. They are stakeholders in the business.

Chris - Well they do say that the proof is in the eating. We have a chicken roasting. Are you confident?

Mark - Yes, reasonably so. We've cooked a lot of chickens recently and we think we know how to do it really quickly and really energy efficiently. In fact we're going to do Yorkshire puddings for you today as well.

Chris - My favourite. Thank you Mark. I’m looking forward to trying this.

Katie - Now, no roast dinner is complete without some veggies so are you going to let me loose on your knives?

Alex - It's not my knives so I'm more than happy to let you use them, but Lawrence might not be so keen.

Katie - If I’m closely supervised. How about that?

Alex - Never touch another chef’s knife. I think that's one of the rules of the kitchen.

Lawrence - I think we can let that go in this case.

Alex - I think we can let it go, yeah. The menu at the moment, our opening menu is entirely vegetarian. We have no meat, no fish on there whatsoever. In fact this chicken that is currently roasting in the oven is the first piece of meat that we've allowed in our kitchen.

Katie - So we've rocked the boat a little bit then?

Alex - You have a little bit but you know, I think that's all part of the fun. I'm not saying that we will never cook meat or fish in this kitchen. There will be times when we have found a farmer that we can work with directly who farms ethically farmed meat and sustainable meat, and that's what we’re putting front and centre of the restaurant.

Lawrence - At the moment, quite simply we’re just enjoying cooking vegetables.

Alex - And at this time of year as well we’re heading into the spring. We’re almost in the middle of spring and the produce that we are working with.

Lawrence - It’s incredible

Alex - We are so fortunate, we are working directly with an organic local farmer who just honestly provides the best vegetables I've ever tasted. The idea came to us actually reasonably quickly about 18 months ago. We cooked together at the Hole in the Wall in Little Wilbraham just outside of Cambridge.

Chris - That was your previous restaurant?

Alex - That was my previous restaurant. So six very enjoyable but very long years. We both went our separate ways, we parted company amicably. I spent some time cooking in various mountainous regions of the world in Switzerland and Ethiopia. And it gave us time to reflect on what we wanted from a restaurant experience, both as a diner and as a restauranteur. We knew that we wanted to work on a sustainable level. For us that means two things: it means from an environmental perspective but also sustainability from a personal perspective as well. So we only work four days a week. We have a very small team, all of whom are fully invested in the philosophy of what we're attempting to do. The biggest thing we can do to diminish our environmental impact is focus much less on the cooking of animal proteins and focus much more on the cooking vegetables and fruits and root vegetables.

Katie - As we are here, I cannot help but ask, I've got two pro chefs in front of me. Can I have a tiny masterclass on chopping some veg?

Lawrence - Of course you can.

Alex - I think we can organise that.

Katie - My chopping skills leave a lot to be desired. I'm gonna have to put that out now, full disclosure; please help me.

Alex - Okay. I suppose lesson number one is keep your fingers out of the way. So I suppose day one at cookery school, you're taught about the claw.

Lawrence - That's day two. Day one's all about eggs. Yeah, day two the claw. It's just a technique that you use to keep the ends of your fingers away from the blade at all times so that no matter how quickly you're chopping you're not gonna cut the end of your finger off.

Alex - So most people when they first pick up a knife they use what you refer to as maybe a tennis racket grip, so you're holding it as you would a tennis racket right on the handle, but that doesn't give you a whole lot of control. It certainly doesn't give you the control that you need for up-and-down, or even side-to-side. So readjust the grip so you've got the hilt of the knife in the back of your hand, and you’re almost holding the top of the blade almost as if you would a pencil.

Katie - It's more like you're playing a violin or a cello bow or something like that?

Alex - As a complete non-musician I will have to take your word on that. So we’ll start off by getting the grip right.

Katie - Okay. A bit more like that?

Alex - So if you just tuck that finger in a little like that and it should feel as if you've got much more control over the blade.

Katie - It does. Chris, I've been chopping wrong all my life.

Alex - What I want you to do is hold the celery in your left hand. So you steady it in your left hand but make sure you keep the tips of your fingers tucked in. And then what you can do is use the part of your finger between your two knuckles as a guide for the blade.

Katie - Ah, so the blade actually rubs up against your fingers each time?

Alex - That's exactly it. So you just shimmy that part of your hand back. The flat of the blade is parallel to the flat of that first part of your finger, and that should give you the control that you need without any risk at all of chopping the ends of your fingers or your nails.

Katie - Okay. They're not as even as yours, Alex

Alex - That's okay. You can work on the evenness later on.

Katie - Well it's all very well I've chopped one stick of celery. If we’re going have a roast dinner we’re going to need to get them cooking. So what exactly are you prepping veggie-wise and how are you going to cook them?

Lawrence - We're going to cook some purple sprouting broccoli with some of the shoots from that as well and first we’re going to start it out with a bit of time in the pan and then we’re going to pop in the oven just to finish off.

A food market with a wide array of different vegetables

Sourcing sustainable food
with Alice Guillaume, Cambridge Food Hub

Where the food we put in the pan actually comes from is key to food sustainability. The concept of eating seasonally when local produce is at its best is nothing new, and eating local, seasonal food can reduce food miles. But actually getting hold of locally-grown produce directly isn’t always easy, especially for big organisations. Katie Haylor and Chris Smith spoke with Alice Guillaume from the Cambridge Food Hub, who are seeking to put local producers in direct contact with local buyers in Cambridgeshire. They took a seat in the dining area of Vanderlyle restaurant in Cambridge to chew the proverbial fat about food miles. First, Alice cautioned that buying locally isn’t necessarily always the greener option...

Alice - If we do manage to buy British food all year round, it's not necessarily the most sustainable option to buy. For example, if you're buying apples in season, that's great, but in order for you to buy British Apple in the middle of summer it had stayed in chilled storage maybe nine months of the year. The energy that goes into chilling that produce for that many months means that actually the carbon footprint of buying British produce, such as apples, out of season is more than if you buy the apples from New Zealand that have come 11,000 miles but have been shipped here.

Katie - So is what you are saying then, it's a bit too simple to just say fewer food miles is more environmentally friendly. It depends a bit on what you're talking about and when you're talking about it?

Alice - Definitely. It also depends on how the food is produced. Maybe food has been stored like the apple example. But if you think about tomatoes, if you're buying tomatoes out of season in the UK, they are grown in artificially heated and lit tunnels, and the carbon dioxide emissions from that method of production are 10 times more than if you grow them naturally in Spain and then ship them over to the UK.

Katie - We're in a county, Cambridgeshire, where there's loads going on in terms of food, how are you seeking to address this issue of it not being as simple as me, a consumer, going to get some strawberries from the field over the road?

Alice - Yeah. So having just said that local is better is too simplified. It is still the case that there is a lot more opportunity for us to buy local produce than we currently have. The infrastructure doesn't exist for, particularly, institutional buyers such as maybe the University, or hospitals, or schools to buy produce that has been grown very close by. One example is about Cambridge University wanting to buy strawberries from Chivers farms, which is near Histon, those strawberries have been grown about 5 km away from where they’re going to be eaten in the University. However, in order for those strawberries to reach the University, the University has to buy them via London, so overall they travel about a hundred kilometres in order to be eaten just 5 km from where they were grown, and this is because there isn't that infrastructure in place to do these direct local sales.

Chris - Sounds nuts although actually it's fruit we’re talking about. Can this be solved though? Because we've all got hooked onto this, haven't we, this mass distribution, mass efficiency model rather than one which is focused on sustainability?

Alice - Yeah. So we get food from all over the world and this has brought massive benefits. We have so much more produce that we can eat. Our diets are way more varied than they were in the past. This is brought nutritional benefits etc. But it does come with a cost - the environmental impact. We think that we can have a positive impact in terms of making local food systems cut emissions but allow people to still have very diverse and interesting and nutritionally positive diets. So the Cambridge Food Hub, what we are trying to do is to put in those missing bits of infrastructure to allow buyers to directly buy from local producers, but instead of each individually going out in their vehicles and collecting that produce which is incredibly fuel inefficient, we want to be that efficient distribution network that can go to all these local producers, gather the local produce and then take it to the buyers within Cambridgeshire.

Chris - But that's very expensive potentially isn't it, because what people really really shop with, is their eye on the price tag. Can you still deliver what people regard as a good choice, a sustainable choice but do it in a way that will compete with what the supermarkets can currently offer you at very low price?

Alice - That's a really interesting point because actually if we think about the price of food that we buy in supermarkets, you get a very low price but it's not accurately reflecting the environmental cost or the cost of the supplier. We want a food system that is fair, that's one of our core values. And in order to be fair it has to benefit everyone that’s involved in the food system. One of the things that we think we can do in order to make sure that the price isn't massively high is by making supply chains shorter. Going straight from the producer to the buyer you skip out a lot of middle stages where you have added mark-up. By making those relationships direct we hope that consumers will get the price that an honest reflection of what it costs and the people that make the food are properly compensated for what they make.

Katie - Now you’re very very new, what are you actually doing right now and what are you hoping to do a bit later on?

Alice - So right now we're really trying to get local producers to join our platform on the open food network where we have a shop front, and we are also getting in contact with buyers maybe farm shops, local groceries, but also we’d love restaurants and café's to become buyers from the food hub as well. So trying to build up that network, get people on our platform, and we're starting to do our initial deliveries to these shops. The impacts that we hope to have are; reducing emissions, so while saying that food miles is more complex than it originally appears, it is the case that we can cut food miles in certain places. We have electric vans that are charged by photovoltaic panels. The efficiency with which you do the deliveries, so planning your routes and making sure that you're not going back on yourself. Making sure that all food that goes into our system ends up somewhere where it's valued, whether it's a high-end restaurant or working with charities and stuff that use produce more flexibly.

this is a picture of 2 men standing next to an oven

The science of a new oven
with Mark Williamson, University of Cambridge

In the kitchen of Vanderlyle restaurant in Cambridge, Chris Smith and Katie Haylor drilled down into the physics of exactly how this new oven, the Eco-Oven as they’re dubbing it, works with inventor Mark Williamson...

Mark - As you can see it look superficially just like any other built-in oven. It's the same size, it makes the same kind of noises, it in fact is plugged into exactly the same kind of electrical supply - 16 amp supply.

Chris - And our chicken is cooking away merrily inside and there are some delicious smells emanating. If that were a conventional oven how would it be cooking whatever we put into it? How does a normal oven work?

Mark - Okay. Well actually the way normal ovens work, a traditional fan oven, is using gently moving hot air - that's the fun oven bit of it. You may use the grill that's in the top of the oven and you may possibly use a hidden element underneath the base of the oven - that's basically it. So a conventional oven just cooks for a certain time at a certain temperature.

Chris - So basically you’re feeding electricity, if it's electric oven, and that electricity heats up a heating element and the overall body of the oven getting hot is then transferring heat to the food?

Mark - Exactly right. That's exactly how it works.

Chris - So what are you doing that's different?

Mark - We've got fundamentally different kinds of heating elements in our oven and our aim has been to get the heat into the food rather than heating up the fabric of the oven. The first heating mode we’ve got in the oven is infrared heating and we are using a very different infrared heating to that you would find coming from a conventional oven with a red hot grill.

Infrared heating is in the form of different waves light and they're space differently apart, and the spacing has very different effects on the food depending on the temperature of the thing that's radiating. So in our oven we’re actually replicating the kind of energy will come from burning wood.

Chris - That that cooks the food differently?

Mark - Oh absolutely. The food actually absorbs the infrared radiation very differently depending on that wavelength. So it goes all the way from really not absorbing anything in terms of the radiation from a traditional oven, to absorbing nearly everything in our oven.

Chris - And how do you make that different flavour - for want of a better phrase - of infrared?

Mark - The way you do it is by using a different temperature for the electrical element that's shining brightly. If it's at a much higher temperature you get a different spacing of the waves.

Chris - And that's what you're doing to get them to be a tighter spacing, so the energy gets in better?

Mark - Exactly. So when you burn a log of wood in a traditional pizza kiln actually that flame is that about 2000°C. The grill in your oven when it glows red hot is only 700°.

Chris - So what are you doing to make the 2000 in your oven then?

Mark - Well, that's a lot of secret stuff in there Chris!

Chris - You're not going to tell me are you?!

Mark - But basically these are very special infrared lamps which run at a very hot temperature.

Chris - Got it. So that's the infrared source. What else does this do differently?

Mark - Okay. So you can see in the oven there, in the base of the oven we actually have an induction heating system which you will not find in any conventional domestic oven. It's the same technology as induction hobs, which some of you may know about. Basically it works by having a coil hidden underneath the bottom of the oven which generates a magnetic field and that transfers the energy into the cooking dish.

Chris - Why do we want to basically create an induction frying pan in the bottom of the oven? Why is that better?

Mark - Well, in a traditional oven, actually the amount of heat that we can get into the bottom of the food is very limited. By doing it this way we are able to dramatically increase the rate at which we can heat the bottom of the food and we do it in a way that heats the food and not the oven.

Chris - Is that because when we plonk a chicken in the middle of oven we often put it on the middle shelf so the energy that's coming into it from below is largely coming from the air circulating, so there is a limit on how much energy you can get in, is that why?

Mark - Exactly right. And in fact, if you look at industrial cooking processes, they go out of their way to ramp up the amount of energy going into the bottom so that they can cook good food quickly because time is money when you're doing this thing in an industrial setting.

Chris - And what else have you got that’s a special modcon?

Mark - Convection air - that's why the traditional oven are called fun ovens - we've got air moving in our oven but it's moving 50 times faster than in a conventional oven.

Chris - Why does that matter?

Mark - Because it transfers heat the food much more quickly. The last thing we've got in there is a really quite sophisticated humidity control system. That actually controls the amount of moisture in the oven, allows us to prevent the surface of certain types of food from drying out.

Chris - So you’re injecting effectively steam into the oven?

Mark - Yeah. We have a small water reservoir in there. The water's converted to steam, a bit like a miniature kettle inside your oven. We think it's a rather clever way of measuring the humidity in the oven and that then controls the amount of steam that's generated. And we can set a recipe - we can have more at the start unless the end, whatever we want.

Chris - How do you know the humidity? Because that's pretty tricky to measure that at oven temperatures, how are you doing that?

Mark - Well, it is tricky and, in fact, in the context of a domestic appliance you can't really put sensors in it that need recalibrating regularly because the thing has got to last for 10 or 15 years. So we found a way of measuring the way that the convection fan in the oven is behaving, from that information, measuring what the humidity is.

Chris - Is that because once the steam's in the air, the air is a bit thicker, a bit denser so the fan's working a bit harder to move it so you can work out how much work the fans doing, and that tells you how in the air is?

Mark - You're on the right track Chris. It’s actually the other way round. The air is more dense than the steam and so in fact the performance of the fan changes to a lower power when you have more steam in the oven. That's what we patented in this oven.

Chris - I want to say it's cool, but it's not it's really hot and it smells amazing actually.

Katie - Once this is cooked, how much energy will you have put into that chicken to make it perfect and delicious? And how does that compare to me using my electric oven at home?

Mark - The first scary thing is that all the domestic ovens are really really inefficient. I mean a typical efficiency for a conventional oven is less than 20%, so the energy you pay for only about 17% of it actually goes into the chicken.

Katie - Is that counting the amount of time - and mine seems to take about three hours - the oven takes to actually to warm up to the right temperature before I even put my chicken in the first place?

Mark - Yes it is. So the pre-heat on oven - I'm not quite sure what's going on with your oven - but on a typical oven, the preheat normally takes about 10 to 12 minutes something like that to get to say 190° C. So yes, it does include that. And there is the time to cook a chicken. So this chicken would have normally haven taken an hour and a half in a regular oven with 10 minutes preheat, say an hour and 40 minutes.

Katie - But you don't have to preheat this oven, is that right?

Mark - No we don't. Basically it starts cooking immediately, within a few seconds it's at full heat and then, as I say, about 35 minutes we're done.

Chris - How much do you think a person would save then if they install this in the house? How much energy, over a working year, are they going to save?

Mark - Depends on the type of food. But if I had to pick an average number the tests so far would indicate somewhere between 15 and 20% saving on electricity usage.

Chris - And what fraction of the household energy bill in the average household - people cooking Sunday roast and the evening meal?

Mark - It's very significant Chris. Actually in many households the built-in oven is the biggest consumer of electricity in the home.

Katie - So how much am I going to save then if I cook my roast chicken in your oven compared to in my oven?

Mark - That depends on how much you're paying for your electricity! It's difficult to put an absolute number on it because of that, but we've worked out that in the lifetime of oven we can probably save you more than half the cost of buying the oven.

Chris - The timer has ticked down to zero, so if you're right Mark, that chicken which we put in 35 minutes ago should be ready to eat.

Katie - Well it certainly smells amazing. I'm guessing that needs to rest a little bit and I heard that we might be having some Yorkshire puddings. As someone from Yorkshire I'm very excited about that.

Mark - Most people will tell you you don't eat meat straight out of the oven. You must let it rest typically 15 minutes is a good amount of time, so we'll use that time to cook some Yorkshire puddings for you.

Katie - So how long do Yorkshire's normally take and how long they take in your oven?

Mark - If we were to pick an average size, a middle size if there is such a thing, probably about 30 minutes/35 minutes in a conventional oven, and we're going to do it in about 18 minutes.

this is a picture of some Yorkshire puddings

50:47 - Analysing the oven

This oven comes it's own PhD student...

Analysing the oven
with Jamie Davidson, University of Cambridge

You know you’re in smart company when the oven that’s cooking your lunch has its own PhD student! Chris Smith spoke to Jamie Davidson from the University of Cambridge, and expert Yorkshire pudding maker, who comes from a department with a track record in food-related research forays...

Jamie - My group actually had a PhD in chocolate a few years ago so yeah, I’m not completely breaking the mould.

Chris - So you are really doing active laboratory research on this?

Jamie - Yeah, exactly. I’m actually looking at optimizing some parts of the design. Little things like how big the nozzles are, how many we need for the air jets, how big a fan we need, the position of the infrared lamps, that kind of thing, so that we really get the maximum possible performance out of the general design.

Chris - How do you actually understand what’s going on in there though? Have you got some kind of computer program that’s making measurements and then you can test different things?

Jamie - Yeah, exactly. I build a big model of the oven using a system called computational fluid dynamics. Basically you split the thing you’re trying to model into tiny little volumes, then you can solve all of your equations numerically over those tiny little volumes. And the model I’m using has 10 million little cubes and prisms making up the oven.

Chris - Essentially you’re dividing the interior of the oven up into lots of little spaces and considering each of them, solving the problems for what’s going on in each one, and then you add them all together to what the whole thing would do or is doing?

Jamie - Exactly.

Chris - How do you know what’s going on in each of the volumes though?

Jamie - we can make sure that the model is accurately capturing reality by devising a bunch of what you call validation experiments. Basically you have to come up with an experiment where you can directly compare results from the model to results from an experiment and minimise the errors of that, and then you can make a decision whether your model is accurate enough or whether you have to make changes.

Chris - Do you cook things with loads and loads of sensors in each of the bits of thing you’re cooking then, so you can work out what’s actually going on and then use that to inform how the model works?

Jamie - Partly. We are doing food trials but food is really complicated. So there will be a lot of different things going on there, you’d have mass transfer from the air in the oven to the food, and from the food into the air. You’d have a coupled heat transfer problem where you’d have to be solving equations for a solid and a fluid. That’s something that we are interested in but not something that really makes a good validation experiment. For validation you really want to be looking at a single piece of physics and whether the model is actually capturing that single piece of physics.

Chris - I suppose one bonus of your research is you actually get to eat it.

Jamie - Yeah well, thankfully now we’re in the restaurant I can eat it but, unfortunately, back in the lab it was very depressing because it’s not a food safe lab so I just had to throw it all away, which was devastating frankly.

Chris - And not very sustainable given this is all about eating and cooking with a conscience.

Jamie - Exactly, exactly. But thankfully now we’re here in Alex’s kitchen we can finally enjoy the fruits of our labour.

A roast turkey still in the oven

The proof of the chicken's in the eating
with Mark Williamson, Alex Rushmer and Lawrence Butler

In the name of science, Chris Smith and Katie Haylor tucked into a roast chicken dinner cooked for them by professional chefs Alex Rushmer and Lawrence Butler, in a brand new oven created by engineer Mark Williamson...

Alex - Right, dinner’s served.

Chris - Are you ready to go?

Alex - Yeah, we are. Sit down and eat.

Chris - Everyone’s at the table already. I’m late to this. So we got chicken, we have sauce, we have amazing Yorkshire puddings, and we have the broccoli.

Lawrence - It’s all right for a mid week lunch isn’t it? This has come together remarkably well. I’m pretty happy with it.

Chris - Shall we actually taste some and then we can decide whether or not we’re going to give Mark the thumbs up or kick him out the door. I saw you sticking the temperature probe in there because, obviously, in a commercial premises like this, you’ve got to be really careful about food safety because of infections and so on, salmonella, campylobacter and so on that you can get from poultry?

Alex - We remove the chicken from the oven when it was what we call coring - core temperature of 75°and then it continues to rise up. So you’re looking at, for chicken, probably around about 80° for it to be fully safe to eat or 75° for a number of minutes.

Chris - And that was after fewer than 35 minutes in the oven which, if that were a conventional oven, how hot would a cold chicken in at get go have got to after 35 minutes?

Alex - I think you are looking at probably about 20/25 degrees below that point. There is no way you could eat a chicken that had been roasted in a conventional oven for that amount of time after 35 minutes.

Chris - Katie looks like she’s going to murder someone if you don’t give her some chicken quite soon.

Alex - Here you go. We’ll solve that problem.

Katie - Thank you very much.

Chris - Are you confident Mark? You looking quite confident over there.

Mark- I always worried but I’m secretly confident, I think, because we’ve done it once or twice before.

Chris - The gravy’s coming Katie. Don’t worry, we’re going to get to you soon, don’t worry.

Katie - Mark, whilst the gravy’s getting dished up, what else have you cooked in this oven? What do you know it can cook and are there any things it can’t cook?

Mark - we started off trying to cook the perfect pizza. Our pizzas are charred on the bottom, which you just cannot do in a conventional oven.

Chris - I don’t know, I’m quite good at that sometimes Mark.

Mark - Well, nicely charred. We can do nice pizzas in about seven or eight minutes versus 30 minutes in a conventional oven with a nice base to them. We’re confident about chicken and similar sort of larger food items. Yorkshire puddings we’ve done, and the work continues. I mean Alex and Lawrence have got their work cut out now to cover the full range.

Chris - I’m just going to get some of the sauce if that’s all right? Oh go on then. Let’s tuck in.

Katie - Cheers.

Chris - Any good Katie?

Katie - I think this is the best chicken I’ve ever had in my life.

Chris - Cooked by a master chef as well, no less. He’s got a mouthful so that’s a good sign if the chef has a mouthful.

Alex - I think the results they speak for themselves really don’t they? The chicken is super juicy. Because we are reducing the cooking time we’re reducing the moisture loss from the chicken so all those juices that might otherwise be lost to the oven, they stay in the chicken because it is only cooking for 30/35 minutes. And I think it’s a superb roast chicken.

Chris - would you serve that up to Greg Wallace? Would he pass muster on that do you think?

Alex - I think Greg would be delighted with that.

Chris - I’m gonna have some. I’m very jealous everyone else is tucking in. Okay Mark, I believe you now.

Mark- Thank you Chris, thank you. There’s a number of different things you can do with it that you just simply can’t do with other ovens. The induction plate in the bottom opens up a whole plethora of different techniques that you can use in ways that you can start out the cooking process in different fashions. We are trying to come up with new recipes for it and bits and bobs, and there’s just so much stuff that we are thinking of that we can try and do with it.

Katie - Do you think it would you change the way that we cook at home?

Mark - Absolutely. It’s going to change how often people do it because of how much quicker it is. I think it’s going to change the quality of the meals that people are able to produce at home. And what me and Alex are trying to do, finding recipes specifically to use for it, that’s going to change how easy it is for people to replicate the same things that we are doing, at home.

Chris - I’m going to raise a toast to Mark’s oven because it’s one thing to come out and make a damn good radio programme, it’s another when you actually get fed. And it tastes absolutely delicious. Cheers Mark.

Katie - Chris, I’ve just realised we’ve been cooked this delicious meal, does that mean we have to do the washing up?

Chris - Yeah. Have you invented a new dishwasher yet Mark?

Mark - The oven actually helps you with the washing up as well. We have a water canister in the top of the oven and if you preloaded it with cold water it captures all the heat from the vent gases in the oven, and at the end of your cooking cycle you will have hot water to do the washing-up with.



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