Tartaric Acid Question
 

Recently I had California juice at 0.3 TA, and wanted to raise it to 0.65
TA. I read several books and found a consistent recommendation to add 3.8
grams of Tartaric Acid per gallon in order to raise the TA by one gram per
liter. Using a conversion factor of 5 grams of Tartaric Acid per teaspoon,
I calculated it would take 13.3 teaspoons of Tartaric Acid to raise the TA
from 0.3 to 0.65. However, knowing it is much easier to raise TA than to
reduce it, I decided to only add 9 teaspoons. After adding the 9 teaspoons,
I checked the TA and it was 0.65! To summarize, I added only 75% of the
recommended amount of Tartaric Acid to achieve the desired TA.

What is the reason for the discrepancy? Is it because the acid titration
test is in accurate, or the conversion between grams of Tartaric Acid to
teaspoons is inaccurate, or some other reason?

Thanks for any insight.

Gary Flye
Charlotte, North Carolina

http://home.carolina.rr.com/winemaking/