Acid Testing

Dan,

In the United States, titratable acid in wine is expressed in grams of acid per 100 milliliters of wine, and titratable acid is calculated as if all of the different acids in the wine were tartaric acid. Please note that 1 gram of acid in 100 grams of wine is equivelent to 1%. The acid content of most finished table wine ranges from 0.55 to 0.85 percent. The desirable acid content depends on style and how much residual sugar is left in the wine. Grapes grown in cool climates often contain too much acid, and fruit grown in warm climates may contain to little acid. Adjusting the starting acid content of the grapes before starting fermentation is one of the more important winemaking tasks. The goal is to have just enough acid to produce a balanced wine.

Lum Del Mar, California, USA

To (briefly) answer your question about pH:

The acid content of wine is expressed as grams per litre or a percentage--this is what you are talking about with the numbers above.

pH indicates the strength of the acid, not it's concentration/amount. pH can certainly be important, since higher pH (i.e. less acidic) results in a greater chance of microbial spoilage--the weaker the acid, the more likely organisms are going to be able to live in your wine. It also affects how much sulphite gets bound up and how much is left to protect your wine.

I suspect that most home winemakers don't measure pH.

I think a simple search of this newsgroup will deliver several threads about pH if you want to know more.

Thanks all for the responses, I know that after I do some more research I'll have more questions.