It is also important to understand the function of the type of acid in the type of wine you are making and to understand how each acid behaves in fermentation. Primary fermentation will consume most of the citric acid, about a 1/3 of the malic acid, but the tartaric acid remains stable. Tartaric acid is also a stronger acidthan malic acid. Thus, as a winemaker, it is best to test both TA and PH. A must with high TA and high PH indicates that you may have a higher concentration of the weaker acid, malic acid. In contrast, tartaric acid will increase acidity, but lower PH.If you are making a fruit wine, especially a wine that will be sweet, you want malic acid present as it adds a fruity, sour character to the wine. However, for some whites and most reds made from grapes, you want to reduce or eliminate malic acid. Therefore, you conduct an MLF fermentation to convert the malic to lactic acid, which adds complexity andsoftens the wine. But if you're making a sweet riesling or gewurztraminer, you want malic acid present to add a fruity, sour flavor that balances the sweetness . Most winemakers who use grapes to make wine hope they don't need to make any adjustment to the acidity, but if they do, they typically use solely tartaric acid, rather than acid blend. However, when making country wines (i.e., non-grape wines), acid blend is used. Because tartaric acid is the dominant acid in grapes,it is a standard practice to do cold stablization for grape wines to reduce the risk of the crystals in the wine when refrigerated. Because acid blend is used for country wines and many fruits contain acids other than predominantly tartaric (e.g., the dominant acid in the apple is malic), cold stabilization of fruit wines is typically not necessary. Edited by: dfwwino