Organic acids in the form of nitrogen compounds. They are the basic building blocks for animal and vegetable proteins and elementary components of enzymes, glutamines and vitamins. There are about 100 different forms, of which about 20 are also contained in grape must. During the fermentation process, the yeasts need certain amino acids to supply nitrogen during metabolism. They have to take these from the must. If the soil is sufficiently supplied with nitrogen, the must also contains a sufficient amount of amino acids (about 1 g/l). The nitrogen content in the grapes is negatively influenced by botrytis (damage to the berry skin and leaching), water shortage, insufficient uptake of nitrogen via the roots and soil cover crop (competition for elementary nutrients).