[dgt20 (OP)]

Was looking at some experiments that would adjust a grapes pH for winemaking in the case the grapes pH was too low or high, i came across a simple one involving CaCO3. What are the steps for this procedure and how does it chemically work?

[puppypower]

Was looking at some experiments that would adjust a grapes pH for winemaking in the case the grapes pH was too low or high, i came across a simple one involving CaCO3. What are the steps for this procedure and how does it chemically work?

The pH of grapes will rarely be too low; too acidity, for wine making. The most common problem in wine making is the pH will be too high. To lower the pH, you add malic acid and/or citric acid depending on the fruit and flavor you want to create. Citrus fruit is high in citric acid and apples are high in malic acid.

If the pH is raised with CaCO3, it may taste better as drinking juice. However, you will have problems with the yeast. If the starting juice is not acid enough, the yeast will create off flavors that will spoil the finished wine. The worse flavor takes like rotten eggs, which makes the final wine undrinkable. It is safer to be too acidic.

If your starting grape juice seems too tart; too acidic, take a sample of the juice and add a little sugar and then taste the sample. Fruits all have a natural acidic tartness that is usually compensated for by a high sugar level. The sugar does not adjust the pH, but it will help your taste buds not taste the acid as much. If your grape juice is too tart, the natural sugars may be low. This juice may be better as a slightly sweetened finished wine. Be very careful with raising the pH, or the yeast will rebel and you make swamp wine.

You could make wine out of any fruit juice. If you started with pure lime juice, the pH will be very low. This is about as low as fruits will go. This will be very tart juice that is very hard to drink.The yeast will be happy and the final wine will be tart, but will still have interesting flavor due to the alcohol and other flavors the yeast will add. In the end, it may taste better if you make it semi-sweet; key lime pie wine.

Years ago I made wine as a hobby. The yeast need the juice to acidic to make good wine. Don't worry about the starting juice seeming to be too tart or too acidic. The yeasts will eat some of the fruit acids and raise the pH.

I used to make wine from orchard fruits like apples, peaches and plums. We would go the farmers market on closing day; Sunday afternoon, and haggles for the extra cases of fruit. They would almost give it away, since it was not worth storing it until the next weekend.  We made an excellent black plum wine.

You can also make wine out of berry bushes and trees, like mulberry, elderberry, cranberries, raspberry, and even sea berries. You can even use rose hips, which are the fruit left behind after rose flowers die back. All you need is acid and sugar to make the yeast happy.

[dgt20 (OP)]

What other simple chemical experiments are there used to alter pH of grapes?

[syhprum]

Are there any special problems with Elderberry I remember a very bad two day hangover after a bottle of homemade Elderberry

[puppypower]

What other simple chemical experiments are there used to alter pH of grapes?

CaCO3 or limestone will work. Make sure to grind the CaCO3 to a powder so it can work faster. You can also use over the counter antacids containing sodium bicarbonate. However, if you are making wine, the yeast win't perform properly when the pH level gets too high.

[lightarrow]

What other simple chemical experiments are there used to alter pH of grapes?

If you add MgCO₃ or Mg(OH)₂ instead of CaCO₃, it helps you feel less muscular fatigue: athlets take sources of Mg²⁺ for that purpose  I don't know which will be the wine  final taste, however...

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lightarrow

[chris]

i came across a simple one involving CaCO3. What are the steps for this procedure and how does it chemically work?

To answer this bit of the question, CaCO₃ is limestone. It has the ability to react with protons (hydrogen ions) to raise pH according to the reaction:

CaCO_3(s) + H⁺ → CO_2(g) + H₂O_(l) + Ca⁺⁺_(aq)

In effect, the calcium carbonate is soaking up the hydrogen ions that are the "acid" in a solution and thereby raising the pH.

You can see this reaction in action every time you de-scale your kettle with some citric acid.