SECTION III.OF WATER.
Aswater is perpetually an object of our senses, and made use of for most of the purposes of life, it might be imagined the nature of this element was perfectly understood: but they who have enquired into it with the greatest care, find it very difficult to form a just idea of it. One reason of this difficulty is, water is not easily separated from other bodies, or other bodies from water. Hartshorn, after having been long dried, resists a file more than iron; yet, on distillation, yields much water. I have already observed, that air is intimately mixed with, and possibly never entirely separated from it, but in avacuum; how is it possible then ever to obtain water perfectly pure?
In its most perfect state, we understand it to be a liquor very fluid, inodorous, insipid, pellucid, and colourless, which, in a certain degree of cold, freezes into a brittle, hard, glassy ice.
Lightness is reckoned a perfection in water, that which weighs less being in general the purest. Hence the great difficulty of determining the standard weight it should have. Fountain, river, or well waters, by their admixture with saline, earthy, sulphureous, and vitriolic substances, are rendered much heavier than in their natural state; on the other hand, an increase of heat, or an addition of air, by varying the expansion, diminishes the weight of water. A pint of rain-water, supposed to be the purest, is said to weigh 15 ounces, 1 drachm, and 50 grains, but, for the reasons just now mentioned, this must differ in proportion as the seasons of the year do from each other.
Another property of water, which it has in common with other liquors, is its fluidity, which is so great, that a very small degree of heat, above the freezing point, makes it evaporate. Experiments to ascertain the proportion steamed away of the quantity of water used in brewing, is an object worthy of the artist’s curiosity; but the purer the water is, the more readily it evaporates. Sea-water, which is supposed to contain one fortieth part of salt, more forcibly resists the power of fire, and wastes much less, than that which is pure.
The ultimate particles of this element, Boerhaave believed to be much less than those of air, as water passes through the pores and interstices of wood, which never transmit the least elastic air; nor is there, says he, any known fluid, (fire excepted, which forces itself through every subject) whose parts are more penetrating than those of water. Yet as water is not an universal dissolver, there are vessels which will contain it, though they will let pass even the thick syrup of sugar, for sugar makes its way by dissolving the tenacious and oily substance of the wood, which water cannot do.
Water, when fully saturated by fire, is said to boil, and by the impulse of that element, comes under a strong ebullition. Just before this violent agitation takes place, I have already observed, it occupies one seventy-sixth more space than when cold: so the brewer who would be exact, when he intends to reduce his liquor to a certain degree of heat, must allow for this expansion, abating therefrom the quantity of steam exhaled.
As water, by boiling, may be said to be filled or saturated with fire, so may it be with any other substance capable of being dissolved therein; but, though it will dissolve only a given quantity of any particular substance, it may, at the same time, take in a certain proportion of some other. Four ounces of pure rain water will melt but one ounce of common salt, and after taking this as the utmost of its quantity, it will still receive two scruples of another kind of salt, viz. nitre. In like manner the strongest extract of malt is capable of receiving the properties belonging to hops: but in a limited proportion. This appears from the thin bitter pelicle, that often swims on the surface of the first wort of brown beers, which commonly are overcharged with hops, by putting the whole quantity of them at first therein; the wort not being capable of suspending all that the heat dissolves, it no sooner cools but these parts rise on thetop. This may serve as a hint to prevent this error, by suffering the first wort to have no more hops boiled therein than it can sustain: but as this incident must vary, in proportion to the heat of the extracts and quantity of water used, some few experiments are necessary to indicate the due proportion for the several sorts of drink. This however should always be extended to the utmost, for the first wort, which, from its nature and constituent parts, stands most in need of the preservative quality the hops impart.
Water acts very differently, as a menstruum, according to the quantity of fire it contains: consequently its heat is a point of the utmost importance with regard to brewing, and should be properly varied according to the dryness and nature of the malt, according as it is applied either in the first or last mashes, and in proportion also to the time the beer is intended to be kept. These ends, we hope to shew, are to be obtained to a degree of numerical certitude.
Nutrition cannot be carried on without water, though likely water itself is not the matter of nourishment, but only the vehicle.
Water is as necessary to fermentation as heat or air. The farmer, who stacks his hay or corn before it is sufficiently dried, soon experiences the terrible effects of too much moisture, or water, residing therein: all vegetables therefore intended to be long kept, ought to bewell dried. The brewer should carefully avoid purchasing hops that are slack bagged, or kept in a moist place, or malt that has been sprinkled with water soon after it was taken from the kiln. By means of the moisture, an internal agitation is raised in the corn, which agitation, though soon stopped, for want of a sufficient quantity of air, yet, the heat thereby generated remaining, every adventitious seed, fallen from the air, and resting on the corn, begins to grow, and forms a moss, which dies, and leaves a putrid musty taste behind, always prevailing, more or less, in beer made from such grain.
That water is by no means an universal solvent, as some people have believed, has been already observed. It certainly does not act as such on metals, gems, stones, and many other substances: it is not in itself capable of dissolving oils, but is miscible with highly rectified spirits of wine, or alchohol, which is the purest vegetable oil in nature. All saponaceous bodies, whether artificial or natural, fixed or volatile, readily melt therein; and as many parts of the malt are dissoluble in it, they must either be, or become by heat, of the nature of soap, that is, equally miscible with oils and water.
When a saponaceous substance is dissolved in water, it lathers, froths, and bears a head; hence, in extracts of malt, we find these signs in the underback. Weak and slack liquors, which contain the salts of the malt without a sufficient quantity of the oils, yield no froth. Somewhat like this happens, when the water for the extract is over-heated, for then as more oils are extracted than are sufficient to balance the salts, the extract comes down as before, with little or no froth or head. This sameness of appearance, from two causes directly opposite to each other, has many times misled the artist, and shews the necessity there is to employ means less liable to error.
This might be a proper place to observe the difference between rain, spring, river, and pond waters; but as the art of brewing is very little affected by the difference of waters, if they be equally soft, but rather depends on the due regulation of heat; and as soft waters are found in most places, and become more alike, when heated to the degree necessary to form extracts from malt; it is evident, that any sort of beer or ale may be brewed with equal success, where malt and hops can be procured proper for the respective purposes. If hitherto prejudice and interest have appropriated to some places a reputation for particular sort of drinks, it has arose from hence; the principles of the art being totally unknown, the event depended on experience only, and lucky combinations were more frequent where the greatest practice was. Thus, for want of knowing the true reason of the different properties observed in the several drinks, the cause of their excellencies or defects was ignorantly attributed to the water made use of, andthe inhabitants of particular places soon found an advantage, in availing themselves of this local reputation. But just and true principles, followed by as just a practice, must render the art more universal, and add dignity to the profession, by establishing the merit of our barley wines on knowledge, not on opinion void of judgment. To place this truth in a fuller light, and to communicate to the brewer the readiest means to examine any waters he may have occasion to use, I have extracted from Doctor Lucas’s Essay on Waters, the experiments he made on the Thames, New River, and Hampstead company’s waters, but without closely adhering to the accuracy this gentleman prescribed to himself; such exactness much better suiting a man of his abilities: for the purposes of brewing it is not of absolute necessity.
Experiments on the Thames, New River, and Hampstead Waters, which in general are in use in the Cities of London and Westminster.
All these waters appear to be sufficiently pure for the common uses of life; the difference between them is very trivial, if any: those of Hampstead approach nearest to the simple state this element is to be wished for. Although it cannot be said to have an immediate relation to this work, yet it may not, perhaps, be disagreeable or useless here to add the quantities of water the cities of London and Westminster, and the adjacent buildings, are daily supplied with.
From the New River Company 57897 Tons per Day.