Raw materials Main raw materials for brewing: malt, hops, water and yeast
Malt
Malt is a brewing barley product.
Brewing barley contains a great deal of starch that converts into fermentable extract in the process of preparing wort syrup in a brewing room. Two-rowed spring barley is the most preferable of all numerous barley varieties.
Special brewing varieties of barley are used for malt production. The quality of brewing barley should have the following characteristics:
— high water absorption and low water sensitivity;
— low content of protein;
— high sprouting by the time of malting;
— high enzyme formation;
— high solubility;
— high yield of extract during malting.
For obtaining brewing barley malt, barley should be thoroughly drawn, graded, soaked and sprouted according to a special technology of malting, and finally dried out. The goal of malting is the accumulation of enzymes in a barleycorn and ensuring their influence on different groups of corn substances, converting high-molecular substances into low-molecular splitting products. Starch-splitting enzymes are of great importance. They subject corn starch to hydrolysis, converting it to fermentable sugars. The most important processes that take place during malting are: malt modification, amylolysis and protein splitting. Parametric variation in the process of corn malting, as well as changing modes of drying of newly germinated malt, enables obtaining different kinds of malt-light, dark, half-light, caramel etc.
Beer\'s aroma, flavour, colour, stability and foaminess depend greatly on qualities of used malt.
Hops
Hop — a perennial dioecious climbing plant. Inflorescences of pistillate plants are used for brewing. They contain bitter resins and essences that impart bitterness and aroma to beer. Hops also facilitate formation of a foamy head, and along with carbon dioxide and spirit are considered to be a natural beer preservative.
Areas of hop cultivation have special climate and soil conditions. Hop picking is followed by drying and pressing of hops for ensuring their long-lasting storage. After cropping, the most part of hops is processed into hop products: essence and grains.
Bitter substances, which are present in lupulin corns, make some 10-25 % of the total mass of hops. The main index of hop bitterness is the content of alpha acid, which amount depends on a hop variety, area of growing, weather and climate conditions, the way of cultivation and hop age.
Depending on the absolute alpha acid level and its content in total resins, all the hop varieties are divided into bitter and aromatic ones. Bitter acids and soft resins that belong to total resins exercise a germicidal effect on different pathogenic microorganisms.
Water
Water is one of the major raw materials for brewing, as it influences the taste and stability of finished products. Water should meet the following requirements: medium total hardness of water (soft water is preferable), neutral pH (acidity level), low content of chlorides, ferrum, manganese and nitrates.
The quality of water, used for brewing, is one of the major factors that define the quality of beer. Water should be microbiologically and radiologically safe, as well as meet all the other standards specified for drinking water: it should be clear, flavourless and tasteless.
Salts that are present in water influence enzymic convertion, fermentation and other biochemical processes, as well as the condition of brewing yeast and the content and condition of inorganic and organic substances of malt. Thereby salts influence organoleptical properties and quality of beer. That is why brewing water must meet higher standards, than drinking water.
Depending on a kind of beer, different water quality standards are applied. Soft water, used for light beers, allows to produce very bright and highly hopped wort. Hardish water, with the presence of hydrogen carbonates, is used for producing dark beers. Half-dark beers are brewed with the use of hard water. Water hardness is determined by carbonate hardness.
In case ionic composition of water does not meet brewing standards, water is conditioned.
Yeast
Brewing yeast belongs to cultivated races and is industrially only applied. Yeast, used for brewing, is divided into races, differing in growth character in nutrient media, cells size and shape, degree of sugars attenuation etc. Yeast fungi are used for brewing; they are unicellular microorganisms, capable of fermenting brewing wort sugars to spirit.
However, brewing yeast acts not only as a fermenter, but, due to metabolism, also as an important taste and flavour-maker.
Yeast chemistry depends on a race, nutrient medium and yeast physiological state. The composition of dry yeast includes: nitrogen-containing substances — 35-65 %, anitrogenous extractive substances — 20-63 %, fats — 2-5 %, mineral matters — 5-11 %. Yeast includes a number of substances that are important from the point of view of physiology; that is riboflavin (vitamin B2), vitamin B1, vitamin PP (nicotinic acid), vitamin B6 (pyridoxin), vitamin C, biotin, inose, pantothenic acid, vitamin E, glutathione, cysteine etc. |
