WINE IS TOO SWEET OR TOO ACIDIC
DESCRIPTION
A wine that tastes too sweet or too acidic (tart) points to an imbalance between sweetness and acidity, most often resulting from incomplete or inadequate processing during winemaking.
CAUSES
A wine that tastes too sweet is the result of either residual, unfermented sugars, i.e. from an incomplete fermentation, or addition of excessive sugar when sweetening wine. A sweeter taste than expected may also result if acidity (i.e. total acidity, or TA) is too low and not properly balanced for the amount of sugar present and one’s taste.
A wine that tastes too acidic is the result of high acidity in the must or wine, and which has not been reduced prior to alcoholic fermentation or by malolactic fermentation (MLF), where the style is appropriate, or during wine aging.
ASSESSMENT
Sweetness and acidity are best assessed and corrected by taste. Residual sugar and total acidity (TA) can also be measured to help with the assessment.
REMEDIAL ACTIONS
If a wine tastes too sweet, you can try adding tartaric acid. First run bench trials adding small amounts of tartaric acid; a 10% tartaric acid solution works best for this purpose. When you have found your “sweet” spot, scale up the amount of tartaric acid used to treat the entire batch. For example, if you decided on adding 0.5 mL of 10% tartaric acid solution to balance sweetness in a 100-mL sample in the trials, that is equivalent to an addition of 0.5 g/L of tartaric acid, and therefore, to treat a 20-L batch of wine, you would need to add 0.5 g/L x 20 L, or 10 g of tartaric acid.
Citric acid can be used in fruit and country wines but not recommended in grape wines, at least not in those that have undergone MLF, as citric acid may get converted into acetic acid, which would increase volatile acidity (VA).
If a wine tastes too acidic, you can try adding table sugar. Run bench trials adding small amounts of table sugar; a 10% sugar solution works best for this purpose. When you have found your “sweet” spot, scale up the amount of sugar solution used to determine how much sugar to add to your batch. Calculations are similar to the ones above for adding tartaric acid. Before adding sugar, be sure to treat and stabilize the wine with sulfite (i.e. potassium metabisulfite) and sorbate (i.e. potassium sorbate) at least 24 hours prior to adding the sugar, otherwise, you risk having the wine start refermenting.
PREVENTIVE ACTIONS
To avoid excessive sweetness in wine, it is usually recommended to ferment it dry, i.e. SG<0.995 (Brix<-1.3), and then sweetening to taste, if desired, by first performing bench trials.
To avoid excessive acidity in wine, it is recommended to deacidify the juice or must, if acidity is considered high, BEFORE starting the alcoholic fermentation. Deacidification using acid-reducing additives can also be done in wine, i.e. after fermentation, but in small amounts only; large acidity adjustments in wine can have a negative impact on quality. There are other acid-reducing techniques possible, depending on objectives and style of wine desired, such as malolactic fermentation (MLF) and cold stabilization.