Tartaric acid dose

Hi Guys....

pH in my merlot must is high - 3.7. I read everywhere to get it below 3.6 but I assume there must be an optimum value to "shoot for". What would be the best value? And how much tartaric acid should I add per gallon to lower it per 0.1? Since the pH scale is a log scale, can I assume a straight-line relationship on the dose per gallon? And do I know what the hell I am talking about here?

I have relied only on pH measurements in the past and have not used a TA test. So I don't know, at this time, what the TA measurement is...

Anyhow, thanks for any help on this one....

A pH of 3.4 is generally considered the target for red wines (3.2 is the target for whites).

I've no idea. Why not take an 8-oz sample, and add a bit of tartartic to it, until the pH reaches the target. Then add the equivalent amount to the main must.

Once you determine the number of grams needed to raise your 8-oz sample to the target pH, do the following calculation:

grams to add to must = (grams added to sample) x 16 x gallons of must.

If this is pre-ferment, you can adjust the pH rather than the TA, and it seems to be the preferred method. After fermentation, the preferred method of measurement is taste.

Tasting is a good idea pre-fermentation too. I'm pretty sure that given sufficient experience one needs no pH meter, titration, refractometer etc.

I'm not _that_ good yet, but I can do a competent sanity check (ballpark estimate) on an adjustment... :^)

Tom S

This is dependent on the specific composition of each must, but for our grapes here in Mid MO, a 1 gram per liter addition (3.785 grams per gallon) will provide the desired effect (0.1 drop in pH). Note that's only for red must: white must requires much less of an addition for the same results.

This is a tough one to determine and takes some experience. The change in pH will not occur immeadiately. The way I started was to do a lab trial, then add HALF of what was calculated from the trial. Then check over the next couple of days.

Ideally the pH is adjusted very first thing. But it's better to get it right and take a couple days to adjust. Just try to keep it early in the ferment if possible.

I do this all the time and rely solely on the taste buds to determine TA.

clyde