PH vs TA

[JimmyT]

I've been reading on here trying to figure out the difference and nothing I've seen comes right out and says it. Am I correct in in concluding in a dumbed down version that TA (tartaric acid) is the total amount of acid and that ph is the strength of that acid?

 

[seth8530]

Here, give this link a read. I think it did a very good job of explaining things.

http://blog.eckraus.com/blog/wine-m...nce-between-ph-and-titratable-acidity-in-wine

 

[JohnT]

I've been reading on here trying to figure out the difference and nothing I've seen comes right out and says it. Am I correct in in concluding in a dumbed down version that TA (tartaric acid) is the total amount of acid and that ph is the strength of that acid?

In short, yes. TA is total amount of acid (weight) and PH is the accumulated strength of the acid present.

 

[ibglowin]

TA doesn't stand for Tartaric Acid. Its Titratable Acidity and measures all acids present in a must including Malic.

I've been reading on here trying to figure out the difference and nothing I've seen comes right out and says it. Am I correct in in concluding in a dumbed down version that TA (tartaric acid) is the total amount of acid and that ph is the strength of that acid?

 

[Turock]

I'm going to take a swing at this and may or may not confuse you further!! Like you, I never understood the validity of TA readings. Everything you read about it always places TA as a more valuable reading than PH--even the E C Kraus article. But I disagree. On another site, I was talking about this very thing with a group of commercial winemakers in Calif. They said some very intersting things about the subject. I made the comment that I think TA measurement is a hold-over from the days before PH meters. TA gave you a direction of where the acid was on the grape or fruit, and where that direction ended up when making adjustments. They pretty much agreed with that comment. They said that they don't even measure TA anymore, which I found quite interesting. What they do is work with PH AND the taste. When they're adjusting high PH must, they bench test as they drop the PH and when the flavor is where they want it, they stop adjusting.

Most of the time, you can't really state exactly WHERE the PH should be for a given grape, and that is why tasting is so important. But we have found thru 25 years of fermenting the same grapes and fruits over and over again, that we have a target PH in mind. BUT--we STILL taste as we are adjusting. And here's why:

TA and PH have no real direct relationship to one another. TA is the acid available to react with sodium hydroxide--unhooking all accessible hydrogen ions. Since the proportions of free and bound hydrogens varies greatly according to varietal, ripeness, growing conditions, etc., so does the relationship between PH and TA. So the best you can say is that higher TA is associated with lower PH and vice versa.

Now knowing PH is very important because it has a powerful effect on the efficiency of SO2. It prevents oxidation and bacterial infection. You need to know the PH in order to know how much free SO2 is needed for preservation. Need to know what the PH is before going into MLF.

To me, PH readings trump TA. I find TA a useless number because ther's nothing you can do with it because of the variables involved in variety, ripeness of the fruit, etc. PH tells you more and is a very usefull number to know.

 

[JohnT]

Very nice summary Turock!

 

[berrycrush]

The way I understand it: It is easier to measure PH than TA. But TA is more truthful in the sense that it does not depend on other factors such as sugar, alcohol and ion concentration or temperature.

 

[Turock]

But what does the measurement TELL you? Can you use it in any logical fashion? TA varies too much to put much value on as to what you should do with the info.

Ph is PH whether there's alcohol or sugar or not. PH readings are not affected by it.

 

[GreginND]

TA doesn't stand for Tartaric Acid. Its Titratable Acidity and measures all acids present in a must including Malic.

Yes, you are measuring all the acids present, but the value is expressed in units of grams of tartaric acid per liter (or percent). Thus, the TA value makes an assumption that all is tartaric even if it's not. It's not that significant but it is how the units are expressed.

 

[BernardSmith]

But what does the measurement TELL you? Can you use it in any logical fashion? TA varies too much to put much value on as to what you should do with the info.

Ph is PH whether there's alcohol or sugar or not. PH readings are not affected by it.

I strongly agree with Turock. TA is an indication of flavor but your mouth is better indicator. And TA I think is a hold over from wine makers use of grapes where the dominant acid is tartaric and not say malic or citric or some other acid - lactic, for example. In many ways they are not that different but they do not taste at all similar. pH on the other hand will give you an indication of the stability of the wine and how much SO2 it will need. It will also give you an idea of how much stress (or not) you may be subjecting the yeast to in a way that TA has nothing to say about that.
I guess what I am saying is that wine making is both an art and a science but you cannot dismiss the art (taste) and imagine that you can make a good wine simply by trying to get the numbers "right".

 

[berrycrush]

But what does the measurement TELL you? Can you use it in any logical fashion? TA varies too much to put much value on as to what you should do with the info.

Ph is PH whether there's alcohol or sugar or not. PH readings are not affected by it.

It tells you the amount of substance, i.e. the acid, just that. Try an experiment:
take a sample and measure both PH and TA, then dilute the sample by a factor of 2 and measure again. Which measurement makes sense?

 

[ibglowin]

It tells you how much Acid (weight) you have in your must pure and simple just like pH gives you a number.

The values for whites and reds are well known and documented. TA responds proportionally to any acid addition or adjustment. pH does NOT.

But what does the measurement TELL you? Can you use it in any logical fashion? TA varies too much to put much value on as to what you should do with the info.

Ph is PH whether there's alcohol or sugar or not. PH readings are not affected by it.

 

[Turock]

As long as a certain PH doesn't cause a problem with SO2 and it tastes good, who cares about the TA? If we're specifically talking about numbers, TA alone won't help you. And I'm sure none of you are saying that. If you want your wine to fall within a certain few points of TA, that's fine. But that is after you make sure the PH is at a good place AND it still tastes good.

 

[ibglowin]

Thats where your argument falls apart. Who cares if your wine has a perfect pH of 3.5 but to get there you added so much Tartaric that your wine is now tart and taste like shat. You can not stick you head in the sand regarding TA and just go by pH you need to balance and work with both numbers.

 

[Turock]

No one is saying "a perfect PH"--rather a PH that won't be so high as to present SO2 problems. Once it tastes good to you, you KNOW that the TA is correct without even testing the number.

 

[ibglowin]

What SO2 problems. You add acid until you get your pH AND TA numbers in the best possible alignment then you sulfite to the level required for your pH once the wine is finished and stable.

There are many commercial wineries especially in WA State turning out award wining wines that are garnering 93, 94, 95 point ratings in Wine Spectator that have 20 year drinking windows associated with them and selling for anywhere from $40 - $80…... and they have pH's in the 3.7 and even 3.8 range. Doesn't sound like they care too much about their pH being a perfect 3.5 at all.

 

[BernardSmith]

I know that Turock can speak for himself but I don't think that he is saying that any specific pH is perfect or even good. I think he is simply saying that when you know your pH then you know how much free SO2 your wine needs for stability. Whether the pH is 3.2 or 3.9 or 4.0 it matters not a whit. What matters is that you know what it is if your aim is to add enough SO2. As for TA what ever the number is is less relevant than whether the wine gives you pleasure when you drink it and that is a matter less of the TA in and of itself than how the TA is balanced with the sweetness and the alcohol content.

 

[Turock]

By a problem with SO2, what I mean is that you don't want the PH so high that it takes a tremendous amount of SO2 for preservation.

With SOME grapes, you can start out with a high PH. And you think to yourself that you should get the PH down to 3.5 or below. But the problem with that is you'll end up with nothing more than a good case of battery acid!!! So the way to approach it is to begin bench testing, while dropping the acid. And you get it to a point where it tastes REALLY good--and the reason for that is because you are adjusting the TA but you're not doing it by some TA number--so then you test the PH. And you find out that the PH is only 3.7!!! Well, you better leave it there or else you'll lose the flavor and the wine will be too acidic if you take the PH any lower. So you adjusted it not by a PH number--not by a TA number. If we're strictly talking numbers--TA tells you nothing. Your pallete is a more accurate indication of where the TA should be than some number. And then you should take a PH reading so you know how much free SO2 the wine needs, and so that you know the PH isn't too low for something like an MLF.

So you are correct in saying there is no perfect PH--nor is there a perfect TA. I agree entirely with you. You've got to go by how it tastes. Because adjustment of taste IS adjustment of TA.

 

[ibglowin]

OK,

I know you (Turock) have been making wine for 20+ years and your palette is probably better than any pH meter but remember the majority of the folks on this board do no have your experience so, until you have that experienced palette most winemakers really need to both taste and know their numbers (pH and TA) and keep track of them for future reference.

 

[Turock]

Well, yes---I cannot argue with that. I don't mind if someone takes TA readings and uses it as a guide as they get their feet on the ground. But they should also know that because TA varies due to variety, ripeness, growing conditions,etc. that the number is not dependable. They should ALWAYS be tasting and stop adjustments when THEY think it tastes good to them. I think PH is a very important number--as I said, PH trumps TA and by that I meant that IT is the number to know. So many new winemakers ask for help with tartness and yet, they are not taking a PH reading! And if they want to take TA readings, I'm OK with that but I hate it when people report a TA reading but NOT a PH. It leaves you in the dark.