Acids occur naturally as grapes grow and during the eventual fermentation process. Wines have lower levels of acid when there is a hot growing season or when the grapes come from warmer regions. In the proper proportion, acids are a desirable trait, giving the wine a distinct character. The three predominant acids in wine are tartaric, malic and citric. Tartaric acid is the principal acid in grapes and is a component that promotes a crisp flavor and graceful aging in wine. A moderate amount of a wine’s acid comes from malic acid, which contributes to fruitiness. A small amount of titratable acidity comes from citric acid. Wine also contains trace amounts of other acids; the least desirable acid in wine is acetic acid, which, when present in more than a nominal amount, gives wine a sour or vinegary aspect.

Total acidity, also called titratable acidity, is the sum of the fixed and volatile acids. In the United States, the total acidity is usually expressed in terms of tartaric acid, even though other acids are also measured. Total acidity directly affects the color and flavor of wine and, depending on the style of the wine, is sought in a perfect balance with the sweet and bitter sensations of other components. Too much acidity makes wine tart and sharp; too little makes wines Žflat and uninteresting. Proper acidity in wine is what makes it refreshing and an ideal accompaniment to food. The proper acid level of a wine varies, with sweeter wines generally requiring somewhat higher levels to retain the proper balance.

Application-Specific pH Electrode

The HI84502 is supplied with the HI1048B glass body pH electrode featuring CPS^™technology to prevent the clogging of the reference junction. Conventional electrodes may clog quickly in biological samples that have a high solids content such as wine must. By design, the HI1048B pH electrode utilizes a polytetrafluoroethylene (PTFE) sleeve junction which controls a steady, predictable flow of electrolyte solution, keeping the junction open. The hydrophobic properties of PTFE repel wetness and coatings.