Grape acid levels, PH, what to do about it, or not

So you get some grapes from a grower you are interested in the "numbers".

Measurments of the sugar level {Brix}, Acid level {PH} , and Total Acidity {TA} are typical measurements that home wine makers are interested in.

Brix and PH should be easy to measure with a hypdometer and a PH meter. TA is not so easy.

I always measure brix since this will determine if I can just start fermentation or if I have to adjust the sugar level before fermentation starts. Sugar level adjustments will get a separate blog entry.

I'm not so concerned with meauring PH and TA, though perhaps I should be..?? Mostly I am relying on getting good grapes {proper numbers} from a good source.

For me, acid level adjustments are done by taste and usally late in the wine making year when the wine is more of less finished with whatever changes it will go through.. The key question for me is; does it taste the way I want it to? e.g. is the acid level too high or too low?

A reason I rely more on taste than a PH measurement is that I have seen widely different numbers from different sources on the same grapes! What if the PH number is not accuate!

Note: a low PH wine tastes like it has high acid taste-wise. e.g. the lower the PH number, the higher the acid level to the taste... can be confusing no?...

If the acid level is too high, I can lower the level through blending in a lower acid wine.

If the acid level is too low, I usually add tartaric acid to bring the acid level up....I'm talking about small levels of acid adjustments like 1/2 teaspoon per 5 gallons of wine. I can always add more if needed....

Though I don't usually measure the PH, I probably should since it is a quantifable number to tell me where the wine is, and how I have changed it during adjustments.

What is "normal" PH for wine? Does that make a difference? --> Yes! for stability. See the article link below!

What is most important is what tastes good to you! This is your wine, make it for your taste! But it should not be out of a normal acid range due to spoilage and stability.

Here's a good general description of PH levels and how it impacts wine and the making process:

http://www.eutechinst.com/techtips/tech-tips42.htm

Wine Characteristic
Low pH Range(3.0 - 3.4) --> more stable, less Bacterial Growth, tastes more acidic...
High pH Range(3.6 - 4.0) --> less stabled, more Bacterial Growth, tastes bland, flat...


The Sauvignon Blanc numbers were: 24.5; TA = 4.7 & pH = 3.7

A PH of 3.7 is on the high side {lower in acid} and would indicate that something should be done to get a more stable wine. I think both Joe and Mike added acid to lower the PH. Perhaps they could comment on this...

There are formulas for computing how much acid to add to change a PH of x to y for z gallons of wine, so it is a fairly straightforward process, just don't add too much!

My thinking about the Sauvignon Blanc is that I have two other wines that I think are high in acid, the Malvasia Blanc and Pinot Grigio, and that blending for these wines with the Sauvignon Blanc is definitely in the plans.

Here's another link that points up the value of tasting the wine when adding acid...

http://www.winemakermag.com/stories/article/indices/6-acid/344-high-ph-low-ta-bottles-wine-wizard

But now that I say that the Malvasia and Pinot Grigio are high in acid {low PH}; I'm thinking that a PH number would be good to have.... Think I'll get a new PH meter....