Unit of measurement for the value or scale (potentia Hydrogenii = strength concentration of hydrogen) for the concentration of active acids in a solution, which is measured using the free hydrogen ions. In viticulture, this is an important criterion for the growth of the vine, the ripeness of the grapes and the flavour and shelf life of the wine. Even the content of the soil (from alkaline to acidic), the temperature and the amount of precipitation during the vegetation cycle as well as the grape variety are of great importance with regard to the concentration in the wine. Among other things, this expresses the degree of acid ity in the soil and in a wine. Although this is related to the acidity in the wine (sum of all acids), it says something completely different.
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