Having thus laid down a concise Theory of Fermentation, we shall now proceed to the Practice.
The Wash being brought to a tepid, or lukewarm State in the Backs, a proper Quantity of a good-conditioned Ferment is added; but if the Ferment be solid, it should be previously broke into small Pieces, and gently thinned either with the Hand, Whisp, &c. in a little of the tepid Liquor. A complete and uniform Solution, however, should not be attempted, because that would greatly weaken the Power of the Ferment, or destroy its future Efficacy. The whole intended Quantity, therefore, being thus loosely mixed with a moderate Parcel of the Liquor, and kept in a tepid State, either by setting it near the Fire, or otherwise, and free from the too rude Commerce of the external Air; more of the insensibly warm Liquor ought to be added, at proper Intervals, till, at length, the whole Quantity is properly set to working together. And, thus, by dividing the Business into Parts, it may much more speedily and effectually be performed, than by attempting it all at once.
The whole Quantity of Liquor being thus set to work, secured in a proper Degree of Warmth, and defended from a too free Intercourse of the external Air, Nature itself, as it were, finishes the Process, and renders the Liquor fit for the Still.
By Ferments, we mean any Substance, which, being added to any rightly disposed fermentable Liquor, will cause it to ferment much sooner and faster than it would of itself; and, consequently, render the Operation shorter; in contradiction to those abusively called so, which only correct some Fault in the Liquor, or give it some Flavour. Hence we see, that the principal Use of Ferments is to save Time, and make Dispatch in Business; whilst they only occasionally, and, as it were, by Accident, give a Flavour, and increase the Quantity of Spirit. And, accordingly, any fermentable Liquor, may, without the Addition of any Ferment, by a proper Management of Heat alone, be brought to ferment, and even more perfectly, though much slower, than with their Assistance.
These Ferments are, in general, the Flowers and Fæces of all fermentable Liquors, generated and thrown to the Surface, or deposited at the Bottom, either during the Act of Fermentation, or after the Operation is finished.
Two of these are procurable in large Quantities, and at a small Expence; we mean, Beer-Yeast and Wine-Lees; a prudent and artificial Management, or Use of which, might render the Business of Distillation much more facile, certain and advantageous.
It has been esteemed very difficult, and a great Discouragement, in the Business of Distillation, to procure a sufficient Stock of these Materials, and preserve them at all times ready for use. The whole Secret consists in dexterously freeing the Matter from its superfluous Moisture; because in its fluid State, it is subject to a farther Fermentation, which is productive of Corruption; in which State it becomes intolerably fœtid and cadaverous.
The Method of exposing it to the Air till it has required a proper Consistence, is subject to great Inconveniencies; and so peculiar and careful a Management necessary, that it rarely succeeds.
The best Way, therefore, is to press it very slowly and gradually, in a thick, close, and strong Canvas Bag, after the manner of Wine Lees, by the Tail-press, till it becomes a kind of Cake; which, though soft, will easily snap, or break dry and brittle between the Fingers. Being reduced to that Consistence, and closely packed up in a tight Cask, it will remain a long Time uncorrupted, preserve its Fragrancy, and consequently, fit to be used for fermenting the finest Liquor.
The same Method is also practicable, and to the same Advantage, in the Flowers or Yeast of Wine; which may be thus commodiously imported from abroad: Or, if these cannot be procured, others of equal Efficacy may be procured from fresh Wine Lees, by barely mixing and stirring them into a proper warm Liquor; whence the lighter, or more volatile and active Parts of the Lees, will be thrown to the Surface, and may easily be taken off, and preserved, by the above-mentioned Method, in any desired Quantity. And hence, by a very easy Process, an inexhaustible Supply of the most useful Ferments may be readily and successively procured, so as to prevent for the future all Occasion of Complaint for want of them, in the Distiller’s Business.