Lowering Ph

[Flame145]

Grapes were Cabernet, Merlot, and Cab. Franc mix.
Starting ph 3.4
Starting TA 7.2
After ML fermebtation Ph = 3.79 and TA = .60
Used wine calculator to raise TA and lower Ph
calculator stated to 9.46 grams of tartaric acid to raise TA to 6.5

I only added 6 grams, wanted to be conservative.
Now Ph = 3.78 (basically the same) and TA = .75

I was trying to lower my Ph to 3.6 for better SO2 protection, I was wanting to bottle soon. This wine is from last September

Any suggestions would be appreciated. Thanks

Oh ya I was usins a Hanna Prep5 ph meter for both Ph and also for calculating TA values

 

[ibglowin]

Let it sit for 24 hours and retest the pH and TA. Things can change rather drastically overnight sometimes. Make sure the wine has been well stirred after adding the Tartaric Acid. Potassium (usually in the skins) can act as a buffer making adjustments to pH and TA difficult. One minute you have a pH of 3.78, the next you have a pH of 3.3. A good rule of thumb is to add 1/2 the calculated amount first, then test, add 1/4, retest, and the last 1/4 and test again. You really want to sneak up on the levels your trying to achieve as they can change fast at times and you can easily overshoot and cause yourself more problems than what you had to begin with.

 

[Flame145]

Mike, I did add the tartaric acid the day prior, and gave it a good 1 minute stir. I gonna re-test ph and ta again this weekend to see if anything has changed.
The only other thing i could think is maybe my Naoh solution for testing TA is old. I purchased it from my LHBS in September when buying grapes.

But like u said, I will wait and try again and see what my numbers are

 

[ibglowin]

NaOH does have a fairly short shelf life once opened. Luckily its pretty inexpensive. You can get away with a single point calibration for pH testing (4.01) but you should do a 2 point calibration for TA testing (4.01 and 7.0) since your going from ~3.6 up to 8.2.

 

[Flame145]

I do calibrate with both 4.01 and 7.0 but my NaOH was purchased Sept. 2011.
My testing for TA is 10 ml of wine, add NaOH until Ph meter reads 8.2
Multiply the # of ml of NaOH by .075 = TA

 

[whackfol]

You don't say how it tastes. I caution shooting for numbers.

As t the TA test, did you standardize your NaOH? Sept 2011 is not an accurate measure.

 

[Flame145]

You don't say how it tastes. I caution shooting for numbers.

As t the TA test, did you standardize your NaOH? Sept 2011 is not an accurate measure.

I bought the NaOH from my LHBS. Don't know what you mean by did I standardize it.
As far as taste goes, the wine tastes pretty good but still needs to age more. The TA number wasn't a big concern for me, it was the ph. I wanted to lower it a bit, I feel as it might be a little high for good SO2 protection.

 

[joea132]

I've got old vine Zinfandel from last cali season. pH was 3.89 and TA was on the higher side. I like the taste and everything about the wine as it sits. I'm letting it stay there and just not aging it for long periods.

The Italians have been making wine without sulfites for years. I don't think it's worth potentially screwing up a perfectly good wine to defend against something that MIGHT be an issue later down the road. Drink it young and hope for better chemistry next time around.

 

[MalvinaScordaad]

I've got old vine Zinfandel from last cali season. pH was 3.89 and TA was on the higher side. I like the taste and everything about the wine as it sits. I'm letting it stay there and just not aging it for long periods.

The Italians have been making wine without sulfites for years. I don't think it's worth potentially screwing up a perfectly good wine to defend against something that MIGHT be an issue later down the road. Drink it young and hope for better chemistry next time around.

Yes but the Romans were using sulfite before they called themselves Italian.

 

[whackfol]

NaOH is not very stable over time regardless of how it is stored. Best practice calls for it to be standardized against a know standard such as potassium acid phthalate or HCl of a similar normality. You never know how or for how long it was stored before you purchased it. As it weakens, your TA measurement will overshoot actual during titration.

 

[Flame145]

NaOH is not very stable over time regardless of how it is stored. Best practice calls for it to be standardized against a know standard such as potassium acid phthalate or HCl of a similar normality. You never know how or for how long it was stored before you purchased it. As it weakens, your TA measurement will overshoot actual during titration.

Can you describe the process to standardize NaOH, so I can learn it. I can up my wine making process. Thanks Bryan

 

[whackfol]

Try this link to EnartisVinquiry:

http://www.enartisvinquiry.com/download/PROTOCOLS/REAGENT STANDARDIZATION.pdf

 

[MalvinaScordaad]

It is probably the same but to me the www.PIwine.com provides a clearer method for the non chemistry major to do this. When you order the Potassium Acid Phthalate, N/10 solution, 4 oz bottle (118 mL) they send you a nice sheet on the method.

 

[Flame145]

Well re-checked my numbers today and to my surprise the Ph was 3.66 , TA was .58 and Free SO2 was 48. So I did do a thing other that bottle that and free up my carboy, which I needed.

 

[ibglowin]

Little better numbers now that things have settled in. Did you use new NaOH on these analysis?

 

[JohnT]

I've got old vine Zinfandel from last cali season. pH was 3.89 and TA was on the higher side. I like the taste and everything about the wine as it sits. I'm letting it stay there and just not aging it for long periods.

The Italians have been making wine without sulfites for years. I don't think it's worth potentially screwing up a perfectly good wine to defend against something that MIGHT be an issue later down the road. Drink it young and hope for better chemistry next time around.

I used to think the same way. After a couple of disasters, and learning that there were steps that I could have made to prevent them, I changed my tune right quick.

Think of it this way. If the Romans had our science and technology, would they avail themselves of it? I think they would. They did what they did because they had no other choice.