Among brewing yeasts, top-fermenting yeasts (strains of the species Saccharomyces cerevisiae) are distinguished by the fact that fermentation usually takes place at temperatures ranging from 16 to 24 degrees Celsius, and bottom-fermenting yeasts (strains of the species Saccharomyces pastorianus, formerly known as Saccharomyces carlsbergensis), in the case of which fermentation takes place at temperatures ranging from 8 to 12 degrees Celsius. In addition to the cultivated yeasts mentioned above, classified as so-called noble strains, brewing also uses non-noble strains, the so-called wild yeasts, which cause spontaneous fermentation. Nowadays, however, fermentation involving wild yeasts is carried out under strictly controlled conditions, with strains selected to provide specific taste and aroma characteristics.
The nutritional and health properties of yeast are also valued. Yeast is rich in vitamins (especially those from the B group) and minerals (including phosphorus, zinc, magnesium, iron, potassium, selenium and chromium). As a result, it has an extremely beneficial effect on the condition of the hair, skin and nails. Due to its high content of B vitamins, the use of yeast-based preparations is also recommended in cases of physical and mental exhaustion and increased exposure to stress. They are also recommended for people who engage in sports during periods of intensive training.
A nutritious yeast drink can be prepared independently. To do this, boil the yeast or pour boiling water over it, and then cool it. To neutralize the specific aftertaste of yeast, it is recommended to add a small amount of warm milk and sugar or honey. However, dietary supplements based on yeast in tablet form are the most popular. In this form, we do not experience the unpleasant taste of yeast. Such preparations also contain other valuable ingredients, such as nettle, horsetail or pansy. Yeast is also used externally. It stimulates hair growth and maintains its healthy appearance. Yeast-based masks applied to the face and décolleté have an anti-acne effect. Yeast regulates sebum secretion and reduces the number of blackheads. Adding even a small amount of yeast to a bath means that its positive effects extend over the entire surface of the body.
Regular use of preparations containing yeast, although they are generally safe for health, may cause gastrointestinal complaints such as bloating or disturbances of the intestinal flora. However, these occur mainly when consuming raw yeast. It should also be noted that yeast may cause allergic reactions. If they occur, treatment should be discontinued.