Beer : Health and Nutrition

66 Chapter Three
Malting
The rst stage of malting comprises the steeping of barley in water at 14–18°C for up
to 48 h, until it reaches a moisture content of 42–46%. Raising the moisture content
allows the grain to start to germinate, a process that usually takes less than a week
at 16–20°C. In germination, the enzymes break down the cell walls and some of the
protein in the starchy endosperm (the grain’s food reserve), rendering the grain friable.
The amylases that break down the starch are produced (or released) in germination and
these are important for the subsequent mashing process in the brewery, which is where
they convert starch to fermentable sugars. Over the years a number of agents have been
employed to assist the maltster to ef ciently produce malts that will satisfy the brewer
in terms of quality and cost. In a great many markets these materials are banned, even
though there is little or no evidence that they are harmful. Thus the natural gibberellin
hormones of the barley, which have a key role in stimulating enzyme production, can be
supplemented with gibberellic acid (GA), which is produced using industrial fermentation
processes (Tudzynski 1999). GA is very closely similar to the native molecules in
barley, but nonetheless is outlawed in the Scotch whisky industry and the North American
brewing industry. Where it is used, its undesirable impact in excessively stimulating
the production of rootlets (which is a waste of potentially fermentable material) has
been countered by the use of potassium bromate. A detailed study showed that this
latter molecule does not survive in signi cant quantities into beer (Brewing Research
International, unpublished). Very few malting operations nowadays use bromate, but it
is widely used in the baking industry where it is used to help bread rise.
There was a time, long ago, when maltsters experimented with the use of formaldehyde,
as an agent to remove tannins from the surface of the grain and render the malt
less prone to giving the beer a tendency to cloud (haze) formation (Macey 1970). I know
of no maltster (or brewer) that has used this material for many years.
One recent development has been the proposal to seed barley with lactic acid bacteria
during the malting process (Laitila et al. 2002). These bacteria are widely employed
in the production of wholesome foodstuffs, e.g. sauerkraut and cheeses, and indeed
natural infection of worts in German breweries has a very long history as an exercise
in ‘naturally’ lowering the pH to a more favourable level. The rationale for using lactic
acid bacteria in the maltings is that they will consume surface nutrients from the grain,
thereby preventing undesirable organisms such as Fusarium from prospering.
Germination is arrested by kilning, in which there is a lowering of the moisture content.
Regimes with progressively increasing temperatures over the range 50 to perhaps
110°C are used to allow drying to < 5% moisture, while preserving those enzymes that
are particularly sensitive to heat. The more intense the kilning process, the darker the
malt that is produced and the more roasted, coffee-like and smoky are the avour characteristics
developed. Essentially, malts used for making very pale lager-style beers are