Acid in wine-making

Ulric le Alefondere

Good acid balance is essential in order to make good wine. It will ensure good flavour & aging qualities in the finished product. Generally, only grapes which are grown under ideal conditions will contain the correct acid balance to produce good wines. Grapes which do not have the correct proportion of acid (and some fruits /vegetables) will need to have acid added to the fermenter *before* fermentation commences.

There are a number of ways to test acid balance (ranging from the a few dollars to a few hundred dollars): litmus paper strips; liquid test kits; electronic pH testing meters.

Initial Acid Content (%)

Red

Wine

White

Wine

Best acid %

.30

.35

.40

.45

.50

.55

.60

.65

.70

.75

.80

.85

.90

Additional tartaric acid (grams) to be added to each litre of wine

dry

 

0.60

3.0

2.5

2.0

1.5

1.0

0.5

0.0

           

medium -dry

 

0.65

3.5

3.0

2.5

2.0

1.5

1.0

0.5

0.0

         

medium

 

0.70

4.0

3.5

3.0

2.5

2.0

1.5

1.0

0.5

0.0

       

med. – sweet

dry

0.75

4.5

4.0

3.5

3.0

2.5

2.0

1.5

1.0

0.5

0.0

     

sweet

medium -dry

0.80

5.0

4.5

4.0

3.5

3.0

2.5

2.0

1.5

1.0

0.5

0.0

   
 

medium

0.85

5.5

5.0

4.5

4.0

3.5

3.0

2.5

2.0

1.5

1.0

0.5

0.0

 
 

med. – sweet

0.90

6.0

5.5

5.0

4.5

4.0

3.5

3.0

2.5

2.0

1.5

1.0

0.5

0.0

 

sweet

0.95

6.5

6.0

5.5

5.0

4.5

4.0

3.5

3.0

2.5

2.0

1.5

1.0

0.5

                               

How to use this table :
  1. Determine the starting acid content of your wine (using whatever testing device you have).
  2. Find the type of wine you are producing, on the left hand side of the table.
  3. Subtract the best acid percentage from the initial content. This will give you the amount of tartaric acid to be added. to your wine.
  4. Dissolve the acid in some of the wine & then add to the fermenting vat.

e.g. You are making a red wine which has an initial acid content of 0.6%. You wish to make this a medium-sweet wine.

The recommended amount of acid for a medium-sweet red is 0.75g /lt.

0.75 – 0.6 = 1.5 Therefore, for every litre of wine you are making, you should add 1.5g of tartaric acid.

So, using the example above, if you are making a 50 litre barrel of wine, you would need to add 50 x 1.5g = 75 grams of tartaric acid to give the correct acid balance.