ed, and on
the kind of malt employed. For stouts and black beers generally, a mashing
temperature of 148 deg. to 150 deg. F. is most usual; for pale or stock ales, 150 deg.
to 154 deg. F.; and for mild running beers, 154 deg. to 149 deg. F. The range of
temperatures employed in brewing English beers is a very limited one as
compared with foreign mashing methods, and does not range further,
practically speaking, than from 140 deg. to 160 deg. F. The effect of higher
temperatures is chiefly to cripple the enzyme or "ferment" diastase, which,
as already said, is the agent which converts the insoluble starch into
soluble dextrin, sugar and intermediate products. The higher the mashing
temperature, the more the diastase will be crippled in its action, and the
more dextrinous (non-fermentable) matter as compared with maltose
(fermentable sugar) will be formed. A pale or stock ale, which is a type of
beer that must be "dry" and that will keep, requires to contain a
relatively high proportion of dextrin and little maltose, and, in its
preparation, therefore, a high mashing temperature will be employed. On the
other hand, a mild running ale, which is a full, sweet beer, intended for
rapid consumption, will be obtained by means of low mashing temperatures,
which produce relatively little dextrin, but a good deal of maltose, _i.e._
sweet and readily fermentable matter.

[Illustration: FIG. 3.--Sparger.]

Diastase is not the only enzyme present in malt. There is also a ferment
which renders a part of the nitrogenous matter soluble. This again is
affected by temperature in much the same way as diastase. Low heats tend to
produce much non-coagulable [v.04 p.0510] nitrogenous matter, which is
undesirable in a stock beer, as it tends to produce fret and side
fermentations. With regard to the kind of malt and other materials employed
in producing various types of beer, pale ales are made either from pale
malt (generally a mixture of English and fine foreign, such as Smyrna,
California) only, or from pale malt and a little flaked maize, rice, invert
sugar or glucose. Running beers (mild ale) are made from a mixture of pale
and amber malts, sugar and flaked goods; stout, from a mixture of pale,
amber and roasted (black) malts only, or with the addition of a little
sugar or flaked maize.

When raw grain is employed, the process of mashing is slightly modified.
The maize, rice or other grain is usually gelatinized in a vessel (called a
_c