# TA vs pH



## GeoS (Feb 19, 2015)

pH measures hydrogen ions while TA measures total acid. I find that if I adjust based on TA the pH goes off the charts. 

Which is more accurate and why? I'm trying to understand how TA vs pH adjustments affect taste.


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## Turock (Feb 19, 2015)

TA is not total acid. It's the acid available to react with sodium hydroxide. Titratable acid.

It's not really possible to say exactly WHERE the PH and TA need to be, especially since TA varies according to ripeness, growing conditions,etc. And because of this, you can't really say there is a lineal relationship between PH and TA.

It's best not to get hung up on numbers here. Adjust until it tastes good to you---then stop, regardless of numbers. As long as your PH is not real high, which would call for inordinate amounts of SO2 for preservation, then I would not worry about where the PH is as long as the flavor profile of the acid is where you like it.


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## GreginND (Feb 19, 2015)

TA adjustments are linear. The amount of titratable protons you add change the number of titratable protons.

pH is not a linear scale. It is a measure of acid strength. And that can be all over the place because every different wine has different components to buffer the acid strength. Adjustments of acid may not be predictable depending on the buffering capacity of the solution.


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## GeoS (Feb 19, 2015)

I understand Titratable Acid is the acid available to react with hydrogen ions. Some use it as an indication of total acid. My question is what does that mean for taste? Some people say to check TA and use the charts and others say to just use pH. I'm trying to establish some coordination between the two. To check TA you can add a base to a solution and measure the volume added until a reaction occurs or it reaches a desired pH, titration method. You can use pH to determine TA so I am looking to see how these are related. 

If they are not related then both cannot be used to determine acid levels and one should not be used. But which one?


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## GeoS (Feb 19, 2015)

And yes, pH is logarithmic thus my belief they are not really related.


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## sour_grapes (Feb 19, 2015)

GeoS said:


> I'm trying to establish some coordination between the two. To check TA you can add a base to a solution and measure the volume added until a reaction occurs or it reaches a desired pH, titration method. You can use pH to determine TA so I am looking to see how these are related.
> 
> If they are not related then both cannot be used to determine acid levels and one should not be used. But which one?



_For a given wine,_ they are related (albeit, not simply). But the relationship varies from wine to wine.


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## GeoS (Feb 19, 2015)

I guess I'm just trying to understand if you check TA and make adjustments based on that why even look at the pH and vice versa. And which method is best if either one is better than the other.


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## Deezil (Feb 19, 2015)

If one method was better than the other, than only one method would exist/be commonplace. They both serve purposes. 

I find in most instances, that pH relates more to SO2 additions, where TA usually relates more to peoples perception/taste of the wine.

You dont want either one to be too high or too low, but getting them both picture perfect isn't as important as the taste is. That said, I don't find it too hard to get the pH between 3.2-3.4 and the TA between 0.55-0.70 %; that's the 'sweet spot' for me, depending on the particular batch.


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## GreginND (Feb 20, 2015)

pH is the important parameter for controlling spoilage bacteria and maintaining proper SO2 levels.


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## wineforfun (Feb 20, 2015)

I know this has been discussed before, but which piece of equipment will measure TA and PH or do you need two?


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## GeoS (Feb 20, 2015)

Well, at least I know I'm not the only one then. I use pH mainly and go for taste. I do look at TA but if it seems off I just go with the pH. Perhaps some more reading into these two is warranted.

wineforfun, you can get a pH meter from many brewing stores or online. I use a Hanna. It's about $35. For TA you can get a kit. It comes with a base and a reagent. You start with a specified amount of wine, add the reagent, then start adding the base until a reaction occurs. The reaction is a change in color caused by the reagent when the pH hits a specific level. Personally, I do not use the reagent, instead I use my pH meter. I suggest researching titration test or titratable acid. There are many good posts and articles on this site. If you still have questions start a thread or post them here and we'll be glad to help as best we can.

One never stops learning. A good teacher is first and for most a great student.


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## wineforfun (Feb 20, 2015)

GeoS,
Thanks for the info. I know I have asked this before and just never followed up as the wines I was making were fine without the tests. Would like to branch out a little so really need to be able to track some things, ie: PH, TA, etc.

I was thinking there was a Vintemeria sp? machine or something like that that did both. It was around $200. I could be mistaken.


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## Enologo (Feb 20, 2015)

Vinmetrica SC-300 tests PH,TA,S02.


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## wineforfun (Feb 20, 2015)

Enologo said:


> Vinmetrica SC-300 tests PH,TA,S02.



Thank you.


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## Deezil (Feb 20, 2015)

You can also use a pH meter in the TA determination process, by starting with the same amount of wine, adding the base and then use the pH meter while adding the reagent until your pH meter reads 8.2. Makes it easier to perform on wines that are harder to see the color change correctly


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## GeoS (Feb 22, 2015)

The vinmetrica is nice. Unfortunately the price tag kept me away from it. I just use the pH and the TA kit. The kit is less than $10. Perhaps I would get better results with the vinmetrica. Maybe time to ease my wife into the pricetag...☺


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## GeoS (Feb 23, 2015)

Here's what I have been able to discern. Although TA and pH are related to acid their use is different.
pH is checked and adjusted according to taste. 
TA 8s checked and adjusted to ensure the proper amount of SO2 (potassium metabisulfite) in the wine. We add SO2 based on the directions on the can, however using TA brings a science to it. The amount of SO2 needed to prevent spoilage is dependant on the pH. If you want to add the proper amount of SO2 you should check the TA to be sure it is in the appropriate range, see charts.

In short pH is adjusted for taste and TA gives a value which corresponds to a range of SO2 required to prevent spoilage.


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## GeoS (Feb 23, 2015)

https://winemakermag.com/547-phiguring-out-ph


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## REDRUM (Feb 23, 2015)

Here's a noob question: do you need to measure acid (whether TA or pH) before fermentation begins, or is it OK to measure later on in the piece and make your adjustments then?


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## sour_grapes (Feb 23, 2015)

GeoS said:


> Here's what I have been able to discern.
> TA [is] checked and adjusted to ensure the proper amount of SO2 (potassium metabisulfite) in the wine. We add SO2 based on the directions on the can, however using TA brings a science to it. The amount of SO2 needed to prevent spoilage is dependant on the pH. If you want to add the proper amount of SO2 you should check the TA to be sure it is in the appropriate range, see charts.
> 
> .... TA gives a value which corresponds to a range of SO2 required to prevent spoilage.



I believe that all the references you make to having the correct TA levels for SO2 should really refer to having the right pH value. The web citation you gave, for example, has a whole section on "The relationship between pH and SO2," and never mentions TA and SO2.


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## Deezil (Feb 23, 2015)

REDRUM said:


> Here's a noob question: do you need to measure acid (whether TA or pH) before fermentation begins, or is it OK to measure later on in the piece and make your adjustments then?



Much better to make the acidity adjustments pre-fermentation. Much better.


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## REDRUM (Feb 23, 2015)

And if, er, that boat has already sailed ... would you recommend that acid adjustment be avoided altogether, or just try to err on the side of caution when adding any additional acids?


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## vernsgal (Feb 24, 2015)

you can still adjust your levels after fermentation.I've read that if adjusting your TA after fermentation to use tartaric acid instead of an acid blend though.Or you could do a MLF which others here would have to explain.


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## GeoS (Feb 24, 2015)

TA and pH are related and you adjust the SO2 based on the acid level so what your saying is correct. However, the SO2 that keep the wine from spoiling is the free SO2. That's the sulfur dioxide that has not bonded with the must. The only way to determine free SO2 is checking TA.


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## cmason1957 (Feb 24, 2015)

GeoS said:


> TA and pH are related and you adjust the SO2 based on the acid level so what your saying is correct. However, the SO2 that keep the wine from spoiling is the free SO2. That's the sulfur dioxide that has not bonded with the must. The only way to determine free SO2 is checking TA.



I don't believe the last part of this statement is true. Free SO2 has little or nothing to do with TA.


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## GeoS (Feb 24, 2015)

You can adjust pH afterwards and may have to tweek it because pH will change during ferment.

Check TA at each stage to and add sulfite as needed but do not adjust acid based on TA.

MLF is converting harsh malic acid to a milder lactic acid and gives a buttery taste. Read up on this one and start a thread if you have questions.


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## GeoS (Feb 24, 2015)

Cmason1957, then please enlighten us on this subject. Usually when giving a dissenting opinion one has justification for it.


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## Deezil (Feb 24, 2015)

GeoS said:


> Cmason1957, then please enlighten us on this subject. Usually when giving a dissenting opinion one has justification for it.



SO2 additions are based off the current Free SO2 and the pH of the wine. TA is more about the taste perception, than anything else. You just have the two backwards is all;



Deezil said:


> I find in most instances, that pH relates more to SO2 additions, where TA usually relates more to peoples perception/taste of the wine.





GreginND said:


> pH is the important parameter for controlling spoilage bacteria and maintaining proper SO2 levels.





sour_grapes said:


> I believe that all the references you make to having the correct TA levels for SO2 should really refer to having the right pH value. The web citation you gave, for example, has a whole section on "The relationship between pH and SO2," and never mentions TA and SO2.





cmason1957 said:


> I don't believe the last part of this statement is true. Free SO2 has little or nothing to do with TA.


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## ibglowin (Feb 24, 2015)

Sorry, free SO2 has nothing to do with TA. 



cmason1957 said:


> I don't believe the last part of this statement is true. Free SO2 has little or nothing to do with TA.


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## Bergmann (Feb 24, 2015)

OBEYWAN: you are whipping the wrong horse.


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## berrycrush (Feb 24, 2015)

This article by Curtis Phillips helps clarifying the relation between SO2 and PH:

************************ from winebusiness.com **********************
...We frequently discuss a wine’s sulfite in terms of “free SO2” and “total SO2” because these are what we can measure. In wine, sulfur dioxide exists in several forms: dissolved sulfur dioxide gas, called “molecular SO2”; unbound bisulfite (HSO3-) or sulfite (SO32-) ions—the sulfite and bisulfite ions are in equilibrium and are usually lumped together with the molecular SO2 under the term “free SO2” or “unbound SO2”; bound bisulfite, where the bisulfite ion has formed a complex with something else, like acetaldehyde, sugars, uronic or ketonic acids. As one might expect, the “total SO2” is the sum of all of these forms.

From a winemaker’s perspective, it’s really the free SO2 that we pay attention to since it is easily measured whereas the molecular SO2 is not.

I find that a distressing number of winemakers overlook the detail that it’s the molecular SO2, not the free SO2, that provides protection from spoilage microbes. The amount of molecular SO2 that is in a solution depends on both the concentration of free SO2 and the pH of the wine. In simple terms, it takes roughly 10 times as much free SO2 to inhibit microbial activity in a wine with a pH of 4.0 than is needed in a wine with a pH of 3.0.

To put this back into terms of free SO2, we see that at pH 3.0 we need only 13.19 ppm free SO2 to achieve 0.8 molecular SO2, whereas at pH 4.0 we need a whopping 124.71 ppm free SO2 to get the same level of protection...
**********************************************************************************************


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## GeoS (Feb 24, 2015)

Berrycrush, thanks. Very intresting, this article contradicts others I have read where they claim it's the free SO2 that prevents spoilage! 

That certainly throws a wrench in the proverbial gear.....

Perhaps I am looking at this backwards. At least we're getting somewhere.

Adjust acid levels based on TA and adjust pH based on spoilage. What doesn't make sense to me is how do I tell how much potassium metabisulfite to add based on the pH?


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## GeoS (Feb 24, 2015)

So I am backwards!

" An important consideration in sulfite management is that the effectiveness of free SO2 decreases as pH increases. Therefore, winemakers are advised to compensate for pH when managing the level of free SO2."

http://winemakermag.com/1301-sulfite-calculator

However, this article states it's the free SO2 that protects the wine.....

Now to find the mathematical relationship......


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## sour_grapes (Feb 24, 2015)

GeoS said:


> Berrycrush, thanks. Very intresting, this article contradicts others I have read where they claim it's the free SO2 that prevents spoilage!
> 
> That certainly throws a wrench in the proverbial gear.....
> 
> ...



It is not really in contradiction. "Free SO2" _includes_ molecular SO2 as well as HSO3 and SO3:



> Free SO2 consists of 3 species: molecular SO2 (directly active in preventing oxidation and spoilage), and two ions, HSO3- (bisulfite) and SO3= (sulfite), which comprise the majority of the free SO2 but are MUCH less reactive than molecular SO2. The percentage of free SO2 existing as molecular SO2 drops as pH rises (2nd column). Thus, at the SAME free SO2 level, wines with higher pH have less molecular SO2, and therefore less SO2 protection.


 From http://www.santarosa.edu/~jhenderson/SO2.pdf


Think about it: If it were only free SO2 that mattered, we would not have to concern ourselves with _p_H at all!




> Now to find the mathematical relationship......



Molecular SO2 = free SO2/[1 + 10^(pH – 1.8)]


Here is another good reference: https://www.extension.purdue.edu/extmedia/fs/fs-52-w.pdf


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## ibglowin (Feb 24, 2015)

Easy Peesy.

Use the handy Winemaker Sulfite Calculator

Or use any of the charts.





GeoS said:


> Adjust acid levels based on TA and adjust pH based on spoilage. What doesn't make sense to me is how do I tell how much potassium metabisulfite to add based on the pH?


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## GeoS (Feb 24, 2015)

Charts schmarts I use a calculator.....

Thanks sour_grapes.


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## GeoS (Feb 24, 2015)

And I found an app for my note 4.....


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## wineforfun (Feb 24, 2015)

Thanks Mike. Chart makes things easy to see.


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## ibglowin (Feb 24, 2015)

Your very welcome.


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## cmason1957 (Feb 24, 2015)

Thanks all for jumping in and agreeing with me. I didn't get a chance to look at my phone all day long at work. I suppose I should have been a Lytle more explanatory there at the first.


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## GeoS (Feb 24, 2015)

The best part is we created a post where people can understand, I hope, this subject. 

Curiosity is the cure to bordom.


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