high TA and pH after MLF

[spinelli01]

Hi - I'm making 5 gallons of wine from Syrah grapes. After primary fermentation, I pressed the wine and decided to try MLF. Prior to MLF, Malic acid was over 500mg/L, TA was around 8.5 g/L and pH was 4.0. After MLF the Malic acid is 0, TA is still 8.5 - 9, and the pH is still 4.0. I use the Accuvin test kits. I'm a little confused with my results, and unsure how to decrease both pH and TA. I'm fairly happy with the taste and smell of the wine, but there is still a fair amount of carbonation. I was a little nervous the wine would spoil until I could figure out what to do, so I placed it in the garage (temps range from 30 - 45 degrees). What do you think has happened during MLF, and how do I correct both pH and TA at the same time?

 

[winemaker_3352]

MLF will not lower TA levels - it metabolized the Malic acid into Lactic acid for a smoother finish.

I would Cold Stabilize it. Try and keep it at temps around 32* for about a week.

 

[spinelli01]

Thanks! Would you sulfite or is the pH too high to be effective?

 

[spinelli01]

Also, I had read somewhere if you cold stabilize with a pH above 3.6, the pH will increase instead of decrease. What is your experience?

 

[grapeman]

Malolactic fermentation does indeed generally lower the TA of the wine. The higher the malic acid, generally the greater the reduction when completed. For every gram of malic acid, only .67 grams of lactic acid is produces with the excess given off as C02. If your wine is fizzy, it probably hasn't completed mlf yet. The only way to be sure is with a chromatography test to confirm it. The Accuvin tests are subject to interpretation of color ranges, which a lot of us read wrong.

If your wine is too high in pH, add tartaric acid- best before fermentation, but better now than never if needed. You can then cold stabilize once the pH has been lowered. Do bench trials before making full aditions.

 

[spinelli01]

Malolactic fermentation does indeed generally lower the TA of the wine. The higher the malic acid, generally the greater the reduction when completed. For every gram of malic acid, only .67 grams of lactic acid is produces with the excess given off as C02. If your wine is fizzy, it probably hasn't completed mlf yet. The only way to be sure is with a chromatography test to confirm it. The Accuvin tests are subject to interpretation of color ranges, which a lot of us read wrong.

If your wine is too high in pH, add tartaric acid- best before fermentation, but better now than never if needed. You can then cold stabilize once the pH has been lowered. Do bench trials before making full aditions.

Makes sense. Do you think the presence of CO2 is affecting the results? I'm heading out to buy a chromatography kit and tartaric acid this evening!

 

[grapeman]

C02 can affect some tests but shouldn't affect a pH meter or TA test kit. You can get rid of it by microwaving a sample to about 150 degrees(if I recall correctly). That drives off the C02 without affecting alcohol. Let it cool and then test it.