_Of practical Fermentation, and the management of the
several sorts of Malt Liquors, to the period, at which
they are to be cleansed or put into the Casks._
The laws of fermentation are universal and uniform; and when it
proceeds regularly, its different periods are known by the different
appearances of the fermenting liquor. As a particular appellation is
given to each of these, it may not be unnecessary here to describe them.
1. The first sign of a wort fermenting is a fine white line, composed
of very small air bubbles, attached to the sides of the tun; the wort
is then said to _have taken yeast_.
2. When these air bubbles are extended over the whole surface of the
must, it is said to be _creamed over_.
3. Bubbles continuing to rise, a thin crust is formed; but as the
fermentation advances rather faster near the sides of the tun, than in
the middle, this crust is continually repelled; from which arises the
denomination of _the wort parting from the tun side_.
4. When the surface becomes uneven, as if it were rock work, this stage
of fermentation, which has no particular use, is distinguished by its
_height_.
5. When the head becomes lighter, more open, more uniform, and of a
greater depth, being round or higher in the middle, than in any other
part, and seeming to have a tendency still to rise, the liquor is
denominated to be of _so many inches, head not fit to cleanse_.
6. This head having risen to its greatest height, begins to sink, to
become hollow in the middle, and, at the same time, more solid, the
colours changing to a stronger yellow or brown; the wort is then said
to be _fit to cleanse_.
After this, no farther distinctions are made; if the fermentation is
suffered to proceed in the tun, the head continues to sink, and the
liquor is often injured.
As the denominations and tastes of liquors brewed from malt are
numerous, it is impossible to specify each separate one; we shall
therefore only particularize such sorts of drinks, as were taken notice
of in the section of extraction, they being most in use; but, from what
will be said concerning them, the method of managing any other malt
liquor may easily be deduced.
Spontaneous pellucidity arises from a due proportion of the oils to
the salts, in the worts, but the advantage of long keeping depends
not only on the quantity of oils and hops the musts possess, but also
on the fermentation being carried on in a slow and cool manner. All
drinks, intended long to be kept, are therefore best formed in cold
weather, and made to receive their yeast at such temperature, as is
set forth in the table. The yeast is to be divided in proportion to the
quantities of wort let down, until the whole, being mixed together,
receives its allotted portion, except so much as is to be put in
just before cleansing. Under these circumstances, drinks, which are
brewed for keeping, are suffered to go through the first process of
fermentation, till they are so attenuated, that the liquor becomes
light, and the head, or the yeast, laying on the surface of the beer,
begins to sink. When, or somewhat before, this head has fallen to
nearly half the greatest height it reached to, a remarkable vinous
smell is perceived, and the liquor, at this term, is to be put into
casks, being first well roused with the remaining part of the yeast, in
the manner mentioned in the preceding section.
By the description given of the origin of yeast, it appears that it is
formed rather of the coarser oils of the worts. If the cleansing is not
done when the head is sunk down to half the greatest height it rose to,
by falling lower, some part of these coarser oils return into the beer,
then under fermentation, and gives it a flat, greasy taste, technically
termed _yeast bitten_. When, on the contrary, beers or ales are removed
too soon from the first tumultuous fermentation, for want of having
been sufficiently attenuated, and from not having deposited their lees,
nor thrown up in flowers their coarser oils, they are less vinous, than
otherwise they would have been, appear heavy, aley, and are said _not
to have their body sufficiently opened_.
The fermentation of common small beer is, through necessity, carried
on so hastily, that it is hardly possible to wait for the signs, which
direct the cleansing of other beers. This drink being generally brewed
and fermented within twenty four hours, its state, with regard to
fermentation, is best judged of, by the quantity of its froth or head
at the time of cleansing, which, in proportion to the heat of the air,
may be determined by the following table.
A TABLE _shewing the depth of head, which common small
beer should have to be properly cleansed, in every season
of the year_.
Heat Head on the beer
of the air. in the tun.
25 Degrees 6 inches.
30 5
35 4-1/4
40 3-1/2
45 2-3/4
50 2
55 1-1/2
60 1
65 3/4
70 1/2
75 1/4
80 just taken.
As it is chiefly by the action of the air that wines are formed, if we
contrive to shift this powerful agent on the surface of a must under
fermentation, and to convey it more forcibly and hastily into the
wort, its efficacy will be renewed, the fermentation accelerated, the
liquor quickly become transparent, and soon be brought to the state of
maturity age might slowly make it arrive at.
Amber, or pale ales, require the hottest extracts pellucidity admits of
to be made strong, and at the same time soft and smooth to the palate;
but, as ales do not admit of any large quantity of hops, which would
alter their nature, there is a necessity to perform hastily the act
of fermentation, and to carry it on to a higher degree than is common
in other malt drinks. The method of exciting and conducting repeated
fermentations, with success, is perhaps not only the most difficult,
but the most curious, part of the process, I shall therefore conclude,
with an account of it, what I have to say with regard to the practice
of fermentation.
The amber wort being let down, at its proper degree of heat, into the
fermenting tun, out of the whole quantity of yeast allowed for this
drink, in the table, page 317, one seventh part must be kept to be used
as hereafter shall be mentioned. Suppose the heat of the air is at 40
degrees, and eight quarters of malt have been brewed for this purpose;
the whole of the yeast required is seven gallons, from which one is to
be reserved.[39] Of the six remaining gallons, one half, or three, are
to be put to the wort oh its first coming down, when the whole must be
well roused, or mixed, thoroughly to disperse the enlivening principle
the yeast conveys, hereby to prevent putrefaction, or foxing in any
part, and of the last three gallons, about three quarts must be added
to the drink, every twelve hours, until it ferments to the highest
pitch of the period mentioned in article 5, page 319. This successive
putting in of yeast is called[40]_feeding the drink_; before and
about the time the head is got to this height, all the dirt or foul
yeast, that rises on the surface, must be carefully skimmed off; it
is easily distinguished from the pure white froth, by its color, and
by the sinking of the head occasioned by its weight. Length of time
might attenuate some of these coarser oils, in a less artificial
fermentation, but as this help is not to be waited for, and every
obstacle to pellucidity must be removed, the brewer’s attention to this
point cannot be too great.--The head of the drink having reached its
utmost height, the reserved gallon of yeast is to be used, in order to
give to the ale a sufficient power to bear the repeated fermentations
it is to undergo, by being beat in, every two hours, with a jett or
scoope, for one quarter of an hour, so that the head on the drink is
each time to be reduced to the least height it is capable of. This
striking in being continued, the drink will periodically require it,
and be damaged if it be neglected. After it has undergone more or less
of these fermentations, in proportion to the heats of the worts and
of the air, the brewer is carefully to observe, when the head ceases
to rise to its accustomed height, and then to examine the drink, by
having the jett filled with it at the bottom, and brought through
the whole body to the top, a small part of which being poured in a
handgatherer, he will see whether the lees form themselves in large
white flakes, and readily subside, and be informed, by the taste,
whether the sweet of the wort is gone off, and the ale become vinous.
If these two circumstances concur, the drink is to be beat in with
the jett as before, but not roused as porter or other beers are; for
the lees, which in this drink are in greater quantity, would, by this
management, so intimately be mixed with it, as with difficulty to
separate themselves again, if at all. It is then time to cleanse it;
but the casks, at all times, more especially in summer, must be well
filled up with clean drink, that is, part of the very drink, which was
cleansed, avoiding that produced in the stillings, as this, for want
of standing a sufficient time, is always yeasty, and the yeast, being
greatly attenuated by the working of the drink, easily dissolves in the
ale, and renders it foul and ill-tasted.
As the right forming of amber ales is looked upon to be the highest
pitch of the art of pale beer brewing, I have dwelt longer on this
article than otherwise it might seem necessary, to shew the connexion
there is between every sort of malt liquors: but it should be observed,
the same method of fermenting it, is to be practised both winter and
summer, varying only the quantities of yeast in proportion to the
season; for where, in winter time, this drink is fed with three quarts
of yeast every twelve hours, half a gallon will answer the same intent
in summer. Upon the whole, the process is contrived to accelerate
fermentation, yet, the more coolly and gently it is performed, the
better will the ales be. I have before hinted, if Madeira wines were
fermented in this manner, they would sooner become fit for use, more
especially as they need no ferment to excite them. However, this method
of forming drink to be soon fit for use, has, either through interest
or prejudice, been taxed with being unwholesome, but upon what grounds,
I must confess I could never yet discover, as no reason of any moment
has ever been alledged for this assertion.