uced, separates in
small flakes like those of curdled soap; and by these means the beer is
rendered less liable to spoil. For nothing contributes more to the
conversion of beer, or any other vinous fluid, into vinegar, than
mucilage. Hence, also, all full-bodied and clammy ales, abounding in
mucilage, and which are generally ill fermented, do not keep as perfect
ale ought to do. Quassia is, therefore, unfit as a substitute for hops;
and even English hops are preferable to those imported from the
Continent; for nitrate of silver and acetate of lead produce a more
abundant precipitate from an infusion of English hops, than can be
obtained from a like infusion by the same agents from foreign hops.

One of the qualities of good porter, is, that it should bear _a fine
frothy head_, as it is technically termed: because professed judges of
this beverage, would not pronounce the liquor excellent, although it
possessed all other good qualities of porter, without this requisite.

To impart to porter this property of frothing when poured from one
vessel into another, or to produce what is also termed a _cauliflower
head_, the mixture called _beer-heading_, composed of common green
vitriol (sulphate of iron,) alum, and salt, is added. This addition to
the beer is generally made by the publicans.[61] It is unnecessary to
genuine beer, which of itself possesses the property of bearing a strong
white froth, without these additions; and it is only in consequence of
table beer being mixed with strong beer, that the frothing property of
the porter is lost. From experiments I have tried on this subject, I
have reason to believe that the sulphate of iron, added for that
purpose, does not possess the power ascribed to it. But the publicans
frequently, when they fine a butt of beer, by means of isinglass,
adulterate the porter at the same time with table beer, together with a
quantity of molasses and a small portion of extract of gentian root, to
keep up the peculiar flavour of the porter; and it is to the molasses
chiefly, which gives a spissitude to the beer, that the frothing
property must be ascribed; for, without it, the sulphate of iron does
not produce the property of frothing in diluted beer.

Capsicum and grains of paradise, two highly acrid substances, are
employed to give a pungent taste to weak insipid beer. Of late, a
concentrated tincture of these articles, to be used for a similar
purpose, and possessing a powerful effect, h