Acid blends are mixtures of acids that are naturally found in wine making grapes. Most blends primarily contain malic, citric, and tartaric acids. Wine making grapes contain more than just these acids but these are the three most abundant acids.
Malic acid contributes tartness to wines. It is the primary acid found in apples for a point of reference. Citric acid, of course, is the dominant acid found in citrus fruits. Tartaric acid also brings tartness to wine and is the dominant acid in cranberries.
An acid blend is used to increase the titratable acidity of a wine. While the point here is to adjust the amount of acids contained within the must it will have an effect on the pH of the must, a measure of the strength of the acids present.
Grape acids are usually at the following concentrations:
- Tartaric = +6 g/L (50%)
- Malic Acid = 4-6.5 g/L (40%)
- Citric Acid = 0.1-0.7 g/L (10%)
LD Carlson acid blend is composed of the following:
- Tartaric Acid = 10%
- Malic Acid = 50%
- Citric Acid = 40%
As you can see the ratio of acids in the acid blend is not the same as you see in wine making grapes. This means that a must treated with an acid blend could have an unnatural mixture of acids. While this isn’t necessarily a bad thing from a taste perspective some wine makers feel like this can lead to balance issues.
Wine makers that choose not to use acid blends will often add acids individually depending upon what they’re trying to accomplish. For instance tartaric acid can be added alone to increase tartness and increase titratable acidity to a more palatable level while avoiding the addition of too much citric acid.
You should also know that different brands of acid blends contain different ratios of acids. If the balance of each individually is something you’re concerned about be sure to ask your supplier.
When To Use It
Acidity is the determining factor of tartness in wine. pH is important to for understanding how strong your acids are but acidity is a measurement of how much total acid you have. So if your wine has very little acid, even if it is a strong acid, the wine will not have a tart component to it. This can lead to flabby wines.
Acid blends should be used to treat the must prior to fermentation. Getting the balance correct not only makes your wine taste better but also helps the yeast do their job better.
Some fruit wine and mead makers will add acid blends just prior to bottling. They measure the amount by taste and not with a scale. This practice is largely discouraged though as it can lead to a grainy mouthfeel and a less integrated final product.
How Much To Use
Before adding any acid blend to your wine, unless you’re following a recipe ingredient for ingredient, you need to understand what your must acidity is before adjusting it. The simplest and least expensive way to figure this out is by using a titratable acidity test kit.
This is a simple titration test kit that measures the concentration of titratable acids. To learn more about acidity check out Understanding Wine Acidity.
After you’ve determined your acidity you can use one teaspoon of acid blend should raise the titratable acidity of your wine by 0.15% (this is according to E.C. Kraus).
One thing you’ll need to keep in mind when adding an acid blend is that it will affect the pH of your wine. While there is not a straightforward relationship between pH and acidity adjusting one will affect the other so be prepared to test and be able to adjust both pH and acidity as needed.
Avoid Malolactic Fermentation
When using either an acid blend or powdered malic acid in your wine you’ll want to avoid malolactic fermentation. It turns out that there are two different types of malic acid, L-malic and D-malic.
L-malic acid is naturally present in grapes and is easily converted to lactic acid by malolactic bacteria. D-malic, on the other hand is not naturally present in grapes and cannot be fermented into lactic acid.
There are test kits available to determine how much of each type of malic acid is present in your wine. However, this would only be of use on a regular basis if you were experiencing malolactic fermentation problems when using grapes you are growing yourself.
Many malic acid powders available for sale at wine making supply stores are made of D-malic acid. Therefore if you want to do a malolactic fermentation but your wine is lacking in titratable acid add tartaric acid alone and then perform the malolactic fermentation.