Getting A Handle On Wine Acidity
By Ed Kraus
Starting your juice out with the proper level of acidity is essential. Acidity is a major component to producing a stable wine with an agreeable balance and overall character. Without controlling acidity the result can be a wine that either tastes too sharp at one extreme, or flat and lifeless at the other.
But there are more reasons for getting a handle on your juice's acidity than just flavor. Having the correct level of acidity will also significantly aid the fermentation process and help to inhibit the growth of unwanted micro-organisms during and after the fermentation.
Having the proper acidity level in the finished wine will also help to keep the negative effects of oxidation to a minimum. Finished wines that are too low in acid can eventually take on a slight raisin or carmel flavor, and in more extreme cases the wine can turn slightly brown or orange in color as well.
Controlling Acidity With Packaged Juices
It is important to note here that when making wine with packaged juices, acidity is not such an issue. Most all of the juices that have been packaged specifically for the purpose of making wine have had their acidity pre-adjusted for you.
This is one of the major benefits of making wine with such products--variables such as acidity do not need to be addressed by the winemaker. They need only to follow the directions that came with the product.
Controlling Acidity With Fresh Fruit
Acidity varies drastically from fruit to fruit. You’ll never pucker eating a banana, but it has fruit acids just as gooseberries or limes do--just less of it. Not only does acidity vary from one fruit to the next, the same fruits can vary in acidity from season to season and from variety to variety.
Also, the amount of fruit you use per each gallon of wine depends on the type of wine being made as well. For example, when making wine from most domesticated grapes, you will use about 15 pounds for every gallon of wine, but when making wine from elderberries only 2 to 4 pounds are necessary for each gallon of wine.
This is because elderberries are packed with much more flavor per pound than grapes. If 15 pounds of elderberries were used to produce 1 gallon of wine, the results would be undrinkable.
So, when you couple the fact that fruits vary in acidity and the amount of fruit called for from one wine to the next varies too, then it starts to become clear that getting a handle on your juice's acidity is a necessity to making wine.
Working With A Recipe
If you have a solid, proven recipe to work from then it is possible to get by without monitoring your juice's acidity. Just add the ingredients to your juice as called for in the recipe.
These recipes, if from a reliable source, will usually put your acidity in the correct range for a sound fermentation. A final tweaking for acidity can be done at bottling time either by taste or by testing.
Testing Your Juice's Acidity
There are two basic ways to check your juice's acidity level. The cheapest and quickest way is to use pH testing strips (litmus papers). They are, for the most part, accurate enough for most home winemaking situations.
However, pH strips are not the most accurate way to check acidity levels. pH strips test for all acids in the juice regardless of how sharp they are to taste. So you can get deceptive readings in rare situations when comparing pH to actual imparted acidic flavor.
When using pH strips, you are looking for a reading of about 3.8 to 3.4. The pH scale works backwards. So it is important to remember that the lower the pH number the higher your acidity will be.
The second and most accurate way to test a juice’s acidity is by doing a titration. With just a couple of minutes of practice, you can easily master this procedure.
A titration kit measures acidity in relation to how sharp the wine actually tastes on the tongue. The readings are usually given in "Percent Tartaric." Which means that, for example, with a reading of .70% tartaric, the acid makes up 7 tenths of 1 percent of the wine's total volume.
Here is a listing of acidity ranges based on the type of wine being made:
.55% to .65% - Fruit Wines
.60% to .70% - Red Wines
.65% to .75% - White Wines
Raising Your Juice's Acidity
Raising the level of acidity in your juice if very simple. You add more acid.
There are three fruit acids commonly used for increasing a juice’s acidity. They are: tartaric, citric and malic. You can buy them individually or buy them blended together as an Acid Blend.
Acid Blend is most commonly used by most winemakers and is what is called for in most wine making recipes. All of these fruit acids come in a granulated form that will dissolve very easily in the juice.
If using a titration reading, making an adjustment is very simple. For every teaspoon of fruit acid you add to a gallon of juice, you will increase the titration reading by .15% tartaric.
This means, for example, that if you have a juice with a reading of .55% tartaric, and you want the juice to read .70% tartaric, all you need to do is add one level teaspoon to each gallon of that wine.
If using pH readings, then it is not so straight forward. pH is not an even scale. That is to say the amount of acid needed to get from 3.9 to 3.8 (remember, backward scale) is different than the amount of acid needed to get from 3.8 to 3.7 for a given volume.
So, there is really no way to tell someone how much acid is needed to get from point A to point B on a pH scale. Trial and error becomes necessary in this case. It is safe to say that 1/4 teaspoon per gallon would be a good starting amount when adjusting by pH.
If the batch is of considerable size you could use a "bench test" method. This is done by taking off a measured portion of juice, say 1 gallon, and add measured portions of Acid Blend to it to establish a dose that can be used for the entire batch.
This is a very safe method, because if you accidentally added too much acid to the sample all you do is add it back to the rest of the batch and start all over.
Lowering Your Juice's Acidity
In most all situations you will be adjusting the acidity up not down, but there are rare occasions where the acidity may need to be lowered. One situation that comes to mind is when making wine with grapes that come from growing regions with shorter seasons than that of say California. The juice from these grapes can be too tart and quite often needs to be lowered.
Or, there may be a time when too much acid is mistakenly added to the juice. In either case your choices are the same:
1. Before the fermentation, you can dilute the juice with a mixture of sugar and water--4 cups sugar to each gallon of water.
2. Or after the fermentation, dilute the finished wine with water or another wine with similar character.
3. In more drastic situations you can use acid neutralizers such as our Acid Reducing Crystals.
4. Or in a very extreme case you can use a combination of any of the above.
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Ed Kraus is a 3rd generation home brewer/winemaker and has been an owner of E. C. Kraus since 1999. He has been helping individuals make better wine and beer for over 25 years.