High pH Low TA Frontenac - Unexpected

Winemaking Talk - Winemaking Forum

Help Support Winemaking Talk - Winemaking Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.


Jul 12, 2013
Reaction score
Never thought I’d experience anything like this, usually have to deal with grapes a bit on the higher side of acidity here in Quebec. Think its because it’s been so hot this summer that things are now reversed. Just finished fermenting and doing a Malo on a blend of Frontenac with a bit of Marquette and St-Croix and the wine turned out with a high pH and low TA.

My TA prior to fermentation was about 10.

Wine measurement is: TA 5.3, pH 3.61

Just checked what normal red wine pH should be: 3.4 to 3.7, so think my 3.6 is bit higher than what is desirable (3.5) and will have to add more SO2 to keep it at 0.8 mg/L of molecular SO2, but it’s the TA at 5.3 that I'm afraid could be a concern, seems to be lower than the normal range of TA 6-7.

Performed titration with usual method: I put a wine sample through coffee filter to remove sediments, I heated 75mls of distilled water to boiling and added 5 mls of wine sample, and took it off the stove and cooled it down and then did the titration. Used a brand new pH probe that is intended for winemaking, that goes with my pH meter. Calibrated using pH buffer 7.0 and 4.0. I did my titration with 0.1 N NaOH and it only took 3.5mls of NaOH to reach the end point pH of 8.2.

Before I cold stabilize I would draw off a sample of it to do a bench trial to see if I end up decreasing the pH or raising the pH before I try stabilizing the whole batch.

Not sure if it would be wise to add a bit of tartaric acid since I’m afraid would have been better to have done this before fermentation, might impart bad flavor to wine?

With bench trial if I end up seeing a drop in pH could I expect the TA to rise, if so might solve the issue?

Over the years this wine would finish at TA between 6.5 and 8, never seen it this low before.


bench trial adding tartaric is appropriate at this time. taste test will determine optimum point.Best method is dissolving 10 grams of acid in 100ml of water. use 100ml samples add one ml first sample, increase each trial sample by 1 ml. each ml equals 1 gram/liter in finished wine.
An oenologist told me that wine is microbial stable at a pH of 3.8, I wouldn't add acid, unless you are doing it for taste.