Naked Science Forum

General Science => General Science => Topic started by: DoctorBeaver on 20/06/2007 20:26:52

Title: Coffee filter machines
Post by: DoctorBeaver on 20/06/2007 20:26:52
I think mine is fairly typical. It has a reservoir for cold water from which a narrow pipe leads up to the top, then curls over so the water can drip into the coffee hopper. The pipe reaches almost to the bottom of the reservoir. When the water heats up it doesn't boil, it just gets very hot.

What is it that makes the hot water go up the pipe?
Title: Coffee filter machines
Post by: Karen W. on 20/06/2007 21:13:12
IS it steam or some kind of steamy vapor suction? Like in a shower when the steam and condensation form a suction and pull the shower curtain in towards your body?
Title: Coffee filter machines
Post by: DoctorBeaver on 20/06/2007 22:33:55
I don't know. If I did I wouldn't be asking, would I  [::)]
Title: Coffee filter machines
Post by: lightarrow on 20/06/2007 22:40:59
I think mine is fairly typical. It has a reservoir for cold water from which a narrow pipe leads up to the top, then curls over so the water can drip into the coffee hopper. The pipe reaches almost to the bottom of the reservoir. When the water heats up it doesn't boil, it just gets very hot.
What is it that makes the hot water go up the pipe?

I don't know how exactly it's made, but if the water reservoir would be tightly closed and with some air up the water, then the air would expand when hot, pushing the water into the pipe.
Title: Coffee filter machines
Post by: DoctorBeaver on 20/06/2007 22:47:12
The top of the reservoir isn't airtight; it just flaps down.
Title: Coffee filter machines
Post by: Soul Surfer on 21/06/2007 10:46:06
The water does not boil in the main vessel but it does boil near the heating elelment.  As the water boils it generates steam and once the bulk of the water is hot enough to make coffee this steam will not condense in the pipe.  It will then rise to lift the hot water in the pipe over the top and into the coffee filter.  The idea is to make the coffee with very hot but not boiling water to preserve the best of the aroma.
Title: Coffee filter machines
Post by: DoctorBeaver on 21/06/2007 12:47:08
Ah. Thank you, Ian  [:)]
Title: Coffee filter machines
Post by: eric l on 21/06/2007 12:56:54
Try "www.howstuffworks.com" and look under "Home" and next under "Home Appliances".  I do not post the link, in order to induce you to explore more of the site.
Title: Coffee filter machines
Post by: DoctorBeaver on 21/06/2007 13:05:59
Thank you, Eric