_Of the signs generally directing the processes of
Brewing, and their comparison with the forgoing Theory
and Practice._
We have now brought our barley wines into the casks, and this on
principles, it is thought, agreeable and consonant to each other. As
the charge of novelty may be alledged, to invalidate what has been
offered, it is but just to pay so much regard to a long, and, upon the
whole, successful practice, as to recite, if not all, at least the
principal maxims and signs in brewing, which hitherto have guided the
artist. By comparing these with the present method, they will not only
illustrate each other, but perhaps cause both to be better understood;
and though, with respect to the art itself, this may be thought rather
a curious than an instructive part, yet we may learn, from hence, that
such practice, which long experience has proved to be right, will
always correspond with true theory.
1. _When a white flour settles, either in the underback or copperback,
which sometimes is the case of a first extract, it is a sure sign such
an extract has not been made sufficiently hot, or, in technical terms,
that_ the liquor has been taken too slack.
Malt, when dried, has its oils made tenacious, in proportion to the
power of heat it has been affected with; the grain, though ground, if
the water for the extraction is not at least as hot as what occasioned
this tenaciousness, must remain in great measure undissolved in the
first extract, and deposit itself as just now was mentioned.
2. _The first extract should always have some froth or head in the
underback._
The oils and salts of the malt, being duly mixed, form a saponaceous
body, the character of which is that, on being shook, it bears a froth
on its surface.
3. _The head or froth in the underback appearing red, blue, purple, or
fiery, shews the liquors to have been taken too hot._
The hotter the water is, when applied to the malt, the more must
the extract abound with oils, and consequently be more capable to
reflect colors in a strong manner. But how precarious this method of
estimating the quality of an extract is, in comparison to that which
the thermometer affords, will appear from the following observation
of Sir Isaac Newton: “Saponaceous bubbles will, for a while, appear
tinged with a variety of colors, which are agitated by the external
air, and those bubbles continue until such time as, growing excessive
thin, by the water trickling down their sides, and being no longer able
to retain the enclosed air, they burst.” Now as these bubbles vary in
their density, in proportion to their duration, the colors they reflect
must continually change, and therefore it is not possible to form an
accurate judgment of the condition and saponaceousness of the extracts,
by the appearance of their froth.
4. _When the grist feels slippery, it generally is a sign that the
liquors have been taken too high._
This appearance proceeds from an over quantity of oil being extracted,
and is the effect of too much heat.
5. _Beer ought always to work kind, out of the cask, when cleansed, but
the froth, in summer time, will be somewhat more open than in winter._
The higher and hotter the extracting water is, the more oils doth
it force into the must; when a wort is full charged with oils, the
fermentation is neither so strong nor so speedy, and consequently the
froth, especially the first, is thin, open, and weak. This improves as
the liquor is more attenuated, and heat, which expands all bodies, must
rarify the yeasty vesicles, the principal part of which is elastic air;
but this open head, even in summer time, improves to one more kind, as
the first, the most active period of fermentation, draws nearer to its
conclusion.
However vague and indeterminate these signs are, it would not be
impossible to bring them to some degree of precision; but, upon the
whole, this method would increase our difficulties, and yet, as to
certitude, be inferior to the rules we have endeavoured to establish,
we think it unnecessary to pursue any farther a research most likely
neither entertaining nor useful.