andyjone - My first question would be what kind of grapes are these and do
you really want the starting TA to be 0.70%.
If you're sure you want to raise acid this much here's what I think will be
required.

You have 11 gallons of crushed grapes. I believe this will contain about
7.4 gallons of juice which is the same as 28009 ml. At 0.3%TA the juice
contains 84grams acid. At 0.7%TA the juice will contain 196grams acid. So,
you will have to add 112grams acid. But, if these were my grapes I would
add portions of the acid, each dissolved in water, and stir the must like
crazy. I would have my pH meter in the must as I did this and would be very
careful not to let pH drop too low. Do these additions slow taking time
between additions so you can be sure to don't let pH drop too low.

Finally, I would have done the acid additions before adding anything to the
grapes, especially the yeast.

Bill Frazier
Olathe, Kansas USA

> wrote in message
ups.com...
> Crushed my grapes and tested the acid 4 times. I got an acid level of
> 0.30 TA three times out of the four. Which means I need to raise my
> acid by 0.40. I have about 11 US gallons....or 42 liters. My
> calculations say I need to add 158 grams of Tataric acid to do the
> trick. Am I anywhere near correct on this. I've never had to add this
> much acid before. The CV grapes seem very low on acid. The Brix is 24.
> The acid kit solutions are a year old. Should I get new solutions and
> retry? I just pitched yeast a couple hours ago.
>