This is because malts are so different. To begin with there are many varieties of barley grown all over the world although the majority of them are not of brewing quality. Barley intended for brewing must satisfy certain criteria, e.g. uniform size, low nitrogen content etc., but within these criteria there is still scope for differences. There are a dozen or more varieties of barley regularly used to make brewing grade malt, each with its own unique characteristics. New varieties are constantly being developed but some of the old favourites such as Maris Otter, Halcyon and Pipkin remain popular. There are different methods of malting and different types of malt which also have an effect on the end product. Although ‘pale malt’ forms the basis of all beers, other malts, and many other factors, combine to produce the endless permutations of colours and flavours which make brewing so fascinating.
It is malt that gives beer its flavour, colour, body, head retention and alcohol content. Although other grains can be malted, barley is the preferred source of fermentable extract.
Barley in its natural state cannot be "mashed". The malting process breaks down the starches contained in the barley husk into their component parts and renders them convertible to fermentable sugars by the naturally occurring enzymes collectively known as diastase.
The first step in malting is to steep the barley in tanks of cool water until the grains have absorbed the maximum amount of moisture. The next step is to spread the barley over the "malting floor" where germination takes place. The grains must be regularly turned to enable the excess moisture to evaporate. The growing shoot, the acrospire, must not be allowed to protrude from the end of the barley kernel. The maltster's skill is his ability to determine when the acrospire has almost travelled the length of the husk. At this point the malt is considered fully "modified".
The malted barley is now transferred to a kiln where it is first dried and then roasted. The differing moisture contents, kiln temperatures and kiln times provide the maltster with the means to produce many different types of malt which in turn enable the brewer to make his own individual beers as simple or as complex as he wishes.
There follows a brief description of the grains stocked by Brupaks. We hope that this will tempt you to experiment with them and widen your brewing horizons.
There is a scale for determining the colour of malt and beer, which is used throughout Europe. The colour is measured in EBC units, where the lowest rating is the palest colour. From the very palest Pilsner Malt at 2.5 EBC to Roasted Barley and Black Malt at anything up to 1500 EBC, there are a vast number of ways to reach the desired beer colour. Only the palest malts, however, contain the enzymes necessary for starch conversion. The bulk of any beer recipe must consist of these malts. The diastatic power of each malt is shown as the maximum percentage that is recommended in the grist.
The first job for the maltster is to separate the barley from the extraneous matter that always accompanies it. Special filters remove stones, soil and other debris before the barley is transferred to silos where it remains until malting time.
Barley to be malted must be plump and moist. This is achieved by steeping it in tanks of water for a few days until the maltster considers the moisture content to be correct. The steeping water is changed frequently to maintain freshness.
The moistened barley is transferred to the germination floor and spread out thinly in order to prevent heat build-up and to facilitate turning which allows oxygen to pass through. Germination cannot proceed without oxygen and high temperatures make it difficult to control the embryonic growth. During germination enzymes are produced which break down the starches and proteins to a form which can be used by the brewer. This is known as modification. Germination usually lasts for between five to seven days before it is halted by heating.
After the barley has been fully modified it is loaded into kilns where it is dried by the application of warm air. Later the temperature in the kiln is raised for the final process of curing. The barley is now known as malted barley or simply as malt. It is now sent out to breweries for the production of beer.