onverter_ or _cooker_) entirely separated from the mash-tun, by means of
steam at a relatively high temperature, mostly with, but occasionally
without, the addition of some malt meal. After about half an hour the
gelatinized mass is mixed with the main mash, and this takes place shortly
before taps are set. This is possible inasmuch as the starch, being already
in a highly disintegrated condition, is very rapidly converted. By working
on the limited-decoction system (see below), it is possible to make use of
a fair percentage of raw grain in the mash-tun proper, thus doing away with
the "converter" entirely.

_The Filter Press Process._--The ordinary mash-tun process, as described
above, possesses the disadvantage that only coarse grists can be employed.
This entails loss of extract in several ways. To begin with, the sparging
process is at best a somewhat inefficient method for washing out the last
portions of the wort, and again, when the malt is at all hard or "steely,"
starch conversion is by no means complete. These disadvantages are overcome
by the filter press process, which was first introduced into Great Britain
by the Belgian engineer P. Meura. The malt, in this method of brewing, is
ground quite fine, and although an ordinary mash-tun may be used for
mashing, the separation of the clear wort from the solid matter takes place
in the filter press, which retains the very finest particles with ease. It
is also a simple matter to wash out the wort from the filter cake in the
presses, and experience has shown that markedly increased yields are thus
obtained. In the writer's opinion, there is little doubt that in the future
this, or a similar process, will find a very wide application.

_Boiling_.--From the mash-tun the wort passes to the _copper_. If it is not
possible to arrange the plant so that the coppers are situated beneath the
mash-tuns (as is the case in breweries arranged on the _gravitation
system_), an intermediate collecting vessel (the underback) is interposed,
and from this the wort is pumped into the copper. The latter is a large
copper vessel heated by direct fire or steam. Modern coppers are generally
closed in with a dome-shaped head, but many old-fashioned open coppers are
still to be met with, in fact pale-ale brewers prefer open coppers. In the
closed type the wort is frequently boiled under slight pressure. When the
wort has been raised to the boil, the hops or a part thereof are added, and
the