ration of the "wort" (as the
liquid portion of the finished mash is called) from the spent grains. The
mash-tun is also provided with a stirring apparatus (the _rakes_) so that
the grist and liquor may be intimately mixed (D), and an automatic
sprinkler, the _sparger_ (fig. 2, B, and fig. 3), which is employed in
order to wash out the wort remaining in the grains. The sparger consists of
a number of hollow arms radiating from a common centre and pierced by a
number of small perforations. The common central vessel from which the
sparge-arms radiate is mounted in such a manner that it rotates
automatically when a stream of water is admitted, so that a constant fine
spray covers the whole tun when the sparger is in operation. There are also
pipes for admitting "liquor" to the bottom of the tun, and for carrying the
wort from the latter to the "underback" or "copper."

The grist and liquor having been introduced into the tun (either by means
of the mashing machine or separately), the rakes are set going, so that the
mash may become thoroughly homogeneous, and after a short time the rakes
are stopped and the mash allowed to rest, usually for a period of about two
hours. After this, "taps are set"--_i.e._ communication is established
between the mash-tun and the vessel into which the wort runs--and the
sparger is started. In this manner the whole of the wort or extract is
separated from the grains. The quantity of water employed is, in all, from
two to three barrels to the quarter (336 lb) of malt.

In considering the process of mashing, one might almost say the process of
brewing, it is essential to remember that the type and quality of the beer
to be produced (see MALT) depends almost entirely (a) on the kind of malt
employed, and (b) on the mashing temperature. In other words, quality may
be controlled on the kiln or in the mash-tun, or both. Viewed in this
light, the following theoretical methods for preparing different types of
beer are possible:--(1) high kiln heats and high mashing temperatures; (2)
high kiln heats and low mashing temperatures; (3) low kiln heats and high
mashing temperatures; and (4) low kiln heats and low mashing temperatures.
In practice all these combinations, together with many intermediate ones,
are met with, and it is not too much to say that the whole science of
modern brewing is based upon them. It is plain, then, that the mashing
temperature will depend on the kind of beer that is to be produc