High TA and high pH

[bathman]

I have just pressed my Cab Sauv and Shiraz after 7 days on the skins - I am finishing off primary fermentation off the skins, mainly due to time and I was happy with the colour.

I tested TA and pH following pressing and found I have both high TA and high pH, compared to what I started with before fermentation. The numbers I have are:

Cab S (before ferm): pH 3.6, TA 7.28g/L
Cab S (after pressing) pH 3.8, TA 10.24g/L

Shiraz (before ferm): pH 3.5, TA 7.95g/L
Shirax (after pressing): pH 3.8, TA 10.8g/L

I am going to wait until fermentation has completed and test again, but assuming the numbers remain similarly high, what options do I have for reducing both TA and pH?

My current thoughts:

1. I intend to carry out MLF, I assume this will further increase the pH (bad) due to converting to weaker Lactic acid and also reduce the TA (good).
2. I could add tartaric acid to reduce pH, say down to pH ~3.6. Then carry out cold stabilisation which hopefully will further reduce the pH, although the TA will have gone up further.

Does anyone have any other ideas how to improve things? Would it be better to add tartaric acid before or after MLF? I'm currently thinking wait to see until MLF is complete then decide what adjustments to make.

Just read something whilst writing this about the need to de-gas a sample before testing for TA, how much of a difference is this likely to make? (I didn't de-gas!)

Thanks

 

[Johnd]

I have just pressed my Cab Sauv and Shiraz after 7 days on the skins - I am finishing off primary fermentation off the skins, mainly due to time and I was happy with the colour.

I tested TA and pH following pressing and found I have both high TA and high pH, compared to what I started with before fermentation. The numbers I have are:

Cab S (before ferm): pH 3.6, TA 7.28g/L
Cab S (after pressing) pH 3.8, TA 10.24g/L

Shiraz (before ferm): pH 3.5, TA 7.95g/L
Shirax (after pressing): pH 3.8, TA 10.8g/L

I am going to wait until fermentation has completed and test again, but assuming the numbers remain similarly high, what options do I have for reducing both TA and pH?

My current thoughts:

1. I intend to carry out MLF, I assume this will further increase the pH (bad) due to converting to weaker Lactic acid and also reduce the TA (good).
2. I could add tartaric acid to reduce pH, say down to pH ~3.6. Then carry out cold stabilisation which hopefully will further reduce the pH, although the TA will have gone up further.

Does anyone have any other ideas how to improve things? Would it be better to add tartaric acid before or after MLF? I'm currently thinking wait to see until MLF is complete then decide what adjustments to make.

Just read something whilst writing this about the need to de-gas a sample before testing for TA, how much of a difference is this likely to make? (I didn't de-gas!)

Thanks

I was reading your post and was thinking about testing without degassing, then you hit it in the last sentence. Carbonation may throw off your reading, so don’t make adjustments til you are positive of your readings. Degassed samples, fresh chems for TA testing, and a confirmed calibration on your pH meter should be on your radar.

 

[bathman]

I just took a small sample in a test tube and gave it a good shake for a couple of minutes and retested it, and TA had come down to 9g/L so that was definitely affecting it.

What is the best way of completely degassing a small sample of wine for accurate testing - is it just shaking?

 

[zadvocate]

I nuked mine for 10-15 seconds in the microwave.