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High Ph + High Ta: Is My Plan Correct?


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#16 andywebster71

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Posted 02 April 2012 - 05:04 PM

Can some please explain the differences and similarities between TA and pH...in layman terms. Does a higher TA usually mean a lower pH or are they completely separate? Any info into explaining the meaning behind these numbers would be greatly appreciated. Thanks!

#17 gregorio

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Posted 02 April 2012 - 06:49 PM

Can some please explain the differences and similarities between TA and pH...in layman terms. Does a higher TA usually mean a lower pH or are they completely separate? Any info into explaining the meaning behind these numbers would be greatly appreciated. Thanks!


In GENERAL. there is a very loose inverse relationship between TA and PH. Higher TA GENERALLY means lower PH. Every grape, every vineyard, every season, every ferment, etc. is different. There is no formula for calculating or predicting one from the other. Remember this and you will be a happier winemaker.
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#18 VitGuy

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Posted 02 April 2012 - 08:54 PM

Can some please explain the differences and similarities between TA and pH...in layman terms. Does a higher TA usually mean a lower pH or are they completely separate? Any info into explaining the meaning behind these numbers would be greatly appreciated. Thanks!


Andy, great question. This is a fairly confusing topic. Like gregorio said, there is a loose correlation. Usually, when people say TA, they are talking about "titratable acidity." TA can also mean "total acidity" which is a very different thing. Here is a very summarized explanation of pH: the measure of the concentration of hydrogen ions (H+) floating around in a solution. So, an "acid" has the ability to "donate" a hydrogen ion (H+) to another molecule.

The opposite of an "acid" is a "base" which has an -OH so it can "accept" the hydrogen ion. When a pH is low there are a lot of hydrogen ions (H+) floating around. In grape juice, TA (titratable acidity) measures mainly the tartaric & malic acid. The titration method uses sodium hydroxide (NaOH) so the available H+'s from tartaric & malic acid are "donated" to the -OH of sodium hydroxide. But, other H+'s that weren't free floating also become "available" because of the high pH created by the sodium hydroxide (NaOH). For example, if I remember correctly tartaric acid has 2 H+'s it can donate, but at juice/wine pH only 1 H+ can be donated (at a pH > ~2). As the pH changes the previously unavailable H+ becomes available (at a pH > ~6). Those pH's are just guesses, I can't remember the exact pH's were the H+'s become unbound.

My philosophy is to pay attention to pH before fermentation & before malolactic fermentation. If a pH is below ~3.75 a lot of the spoilage microbes are not able to function. TA, on the other hand, is really more important when the wine is finished as it helps with mouthfeel and the preceived acidity in a wine. TA can also help with harvesting decisions, but, I like to follow brix & pH much more.

#19 Reverend Drake

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Posted 07 April 2012 - 11:45 PM

Those are totally exceptable numbers.

They're even acceptable... smileycheers.gif
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#20 VitGuy

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Posted 08 April 2012 - 06:45 PM

They're even acceptable... smileycheers.gif


Haha...oops :)




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