It follows from thence, that some worts will boil sooner than others, receive their heat in a less time, and be saturated with less fire; but, as it is impossible, and, indeed, unnecessary, to estimate exactly the quantities of oils, salts, and water contained in each different wort, it is out of our power previously to fix, for any one, the degree of heat it is capable of. This renders the thermometer in this case useless, and obliges us to depend entirely on experiment, and to observe the signs which accompany the act of ebullition.

Fire, as before has been mentioned, when acting upon bodies, endeavours to make its way through them in right lines. A wort set to boil, makes a resistance to the effort of fire, in proportion to the different parts it is composed of. The watery particles are, it is imagined, the first, which are saturated with fire, and becoming lighter in this manner, endeavour to rise above the whole. The salts are next, and last of all the oils. From this struggle proceeds the noise heard when the wort first boils, which proves how violently it is agitated, before the different principles are blended one with another. While this vehement ebullition lasts, we may be sure that the wort is not intimately mixed, but when the fire has penetrated and united the different parts, the noise abates, the wort boils smoother, the steam, instead of clouding promiscuously as it did at first round the top of the copper, rises more upright, in consequence of the fire passing freely in direct lines through the drink, and when the fierceness of it drives any part of the drink from the body of the wort, the part so separated ascends perpendicularly. Such are the signs by which we may be satisfied the first wort, or the strongest part of the extracts, has been so affected by the fire, as to become nearly of one taste. If, at this time, it is turned out of the copper, it appears pellucid, and forms no considerable sediment.

The proper time for the boiling of a wort hitherto has been determined, without any regard to these circumstances; hence the variety of opinions on this subject; greater, perhaps, than on any other part of the process. While some brewers would confine boiling to so short a space as five minutes, there are others who believe two hours absolutely requisite. The first allege, that the strength of the wort is lost by long boiling; but this argument will not hold good against the experiment of boiling a wort in a still, and examining the collected steam, which appears little else than mere water. Those who continue boiling the first wort a long time, do it in order to be satisfied that the fire has had its due effect, and that the hops have yielded the whole of their virtue. They judge of this by the wort curdling, and depositing flakes like snow. If a quantity of this sediment is collected, it will be found to the taste both sweet and bitter, and if boiled again in water, the decoction, when cold, will ferment, and yield a vinous liquor. These flakes, therefore, contain part of the strength of the wort; they consist of the first and choicest principles of the malt and hops, and, by their subsiding, become of little or no use.

It appears, from these circumstances, that boiling a first wort too short or too long a time, is equally detrimental, that different worts require different times, and these times can only be fixed by observation.

The first wort having received, by the assistance of the fire, a sufficient proportion of bitter from the hops, is separated therefrom. The hops, being deprived of part of their virtues, are, on the other hand, enriched with some of the glutinous particles of the malt. They are afterwards, a second, and sometimes a third time, boiled with the following extractions, and thereby divested not only of what they had thus obtained, but also of the remaining part of their preservative qualities. The thinness and fluidity of these last worts render them extremely proper for this purpose. Their heat is never so intense as that of the first, when boiling; for, as they consist of fewer oils, they are incapable of receiving so great a degree of heat. This deficiency can only be made up by doubling or tripling the space of time the first wort boiled, so that what is wanted in the intenseness of heat, may be supplied from its continuance.

The following table is constructed from observations made according to the foregoing rules.

A TABLE shewing the time each wort requires to boil for the several sorts of beer, in every season.

Brown beer, keeping pale strong and keeping small beer.Small beer.amberBurtonsmall
after
amber		keeping
small
after
amber
╭━━━━━━━━━━━━━^━━━━━━━━━━━━━╮╭━━━━━━^━━━━━━╮
Degrees
of
heat
in the
air		 hourshourshourshourshourshourshourshourshourshours
35°1241/2121/21/212
401241/2121/21/212
451241/2121/21/212
501241/2121/21/212
55 24 1½33/43/412
60 24 1½33/411½2
1 wort 2 wort[24] 3 wort1 wort 2 wort 3 wort.

It may, perhaps, be objected, that, by a long boiling of the last worts, the rough and austere parts of the hops may be extracted, and give a disagreeable taste to the liquor; but it should be observed, this only happens, either in beers to be long kept, or in such as are brewed in very hot weather. In the first case the roughness wears off by age, and grows into strength, and in the last, it is a check to the proneness musts have in such seasons to ferment.