122 ELEMENTAKY AGRICULTURAL CHEMISTRY 



dried in a kiln at a temperature high enough to destroy the 

 vitality of the embryo. The plumule and radicle are then re- 

 moved — they constitute rnalt culms — and the malt is then ready 

 for use in the preparation of wo7% The most important change 

 produced by malting is the production of a considerable quantity 

 of a peculiar unoi'gaiiised ferment, or enzyme, known as diastase^ 

 which has the power in the presence of warm water of con- 

 verting starch into sugar. When malt is mashed — i.e., treated 

 for some time with hot water — this change begins, and the 

 liquid gradually becomes charged with sugar, the starch of the 

 barley grain at the same time disappearing. The quantity of 

 diastase in malt is so large that it is capable of converting 

 much larger quantities of starch into sugar than are contained 

 in the malt itself. Consequently unmalted barley or other 

 cereal is sometimes added with the malt. The resulting liquor, 

 known as wort, is then submitted to alcoholic fermentation by 

 means of yeast, hops are added to impart a bitter flavour, and 

 heer or ale results. Barley is also used as food for animals, in 

 England particularly for pigs. 



"Pearl barley" is the grain divested of its outer fibrous 

 coat. 



Average Composition of Barley and Barley Straw 



Oats (Avena sativa) will ripen in a cooler "climate than wheat 

 or barley. The grain retains a large proportion of husk, and 

 varies in size and shape considerably in the different varieties. 



