Well-brewed drinks should not only preserve themselves sound their due space, in order to be meliorated by time; they should likewise be fine and transparent.—These circumstances prove the artist’s skill and care, as well as the salubrity of the drink; and are the surest signs of a well-formed must, and of a perfect fermentation. If then the rules for obtaining these ends can be deduced from the foregoing principles and experiments, we may flatter ourselves with possessing a theory, which will answer our expectations in practice.
According to the laws of nature discovered by Sir Isaac Newton, the spaces between the parts of opaque bodies are filled with mediums of different densities, and the discontinuity of parts, each in themselves transparent, is the principal cause of their opacity. Salts in powder, or infused in an improper medium, will intercept the light; gums make a muddy compound, when joined to spirits; and oils, unassisted by salts, refuse to be incorporated with water. Musts, therefore, whose constituent parts are not capable of being dissolved by water into one homogeneous body, are not fit, either for a perfect fermentation, or a pellucid drink.
Length of time, which improves beers and wines, often rectifies our errors in this respect; for the oils being, by various frettings, more attenuated, and more intimately mixed, the liquor is frequently restored, and becomes of itself pellucid. Yet I never found this to succeed, where the error upon the whole of the dryness of the malt, and the heat of the extracts, exceeded the medium by 10 degrees.
Art has also, in some measure, concurred with nature to remedy this defect. When beers or wines have been suffered to stand, till they are rather in an attracting than in a repelling state, that is, when their fermentations and frettings apparently stand still; then, if they do not become spontaneously fine, they may be precipitated, by mixing with them a more ponderous fluid. The floating particles, that occasioned the foulness, are, by this means, made to subside to the bottom, and leave a limpid wine: but the power of dissolved isinglass, the ingredient generally used for this purpose, seldom takes effect, when the error exceeds the medium, as before, by more than 10 degrees.
Other ingredients, indeed, have been used, which carry this power near 10 degrees farther. It is not my province to determine, whether such be salutary: undoubtedly it would be better if there were no occasion for them. Beyond these limits, precipitation has no effect; the liquor, which cannot be fined thereby, if attempted, by increasing the quantity of the precipitants, will be overpowered by the menstruum, and injured in its taste. How frequent this last case of cloudiness is, would answer no purpose in this place to enquire. The use of doubtful ingredients, and such errors as have been mentioned, need no longer blemish the art, when a constant and happy practice, will be both the effect and the proof of a solid and experimental theory.
Beers which become bright of themselves, or by time alone, as well as those precipitated either by dissolved isinglass, or by more powerful means, each possess their respective properties in a certain latitude or number of degrees; and as these effects arise wholly from the heats employed in drying the malts, and in forming the extracts, the following table will be of use to point out the limits, within which each drink may be obtained.
A TABLE, shewing the tendency beers have to become fine, when the malt, in drying and extracting, has been impressed with heats, the medium of which answers to the following degrees, supposed to be brewed and kept in the most eligible manner.
| Deg. | ||||||
| 119 | White, | } | Immediately. | } | Latitude of musts which fine spontaneously. | |
| 124 | Inclining to yellow, | |||||
| 129 | Yellow, | 2 Months. | ||||
| 134 | High yellow, | 4 Months. | ||||
| 138 | Amber, | 6 Months. | } | Latitude of musts which fine by precipitation. | ||
| 143 | Light brown, | 8 Months. | ||||
| 148 | Brown, | 10 Months. | ||||
| 152 | High brown, | 12 Months. | ||||
| 157 | { | Brown, inclining to black, | } | 14 Months. | } | Latitude of heats which cannot form musts, so as to answer the intent of becoming wholesome beer. |
| 162 | { | High brown speeckled with black | } | 18 Months. | ||
| 167 | High brown half black | 18 Months. | ||||
| 171 | Coffee color, | } | 20 Months. | |||
| 176 | Black, | |||||
The difference between the heat for forming grapes, and the greatest heat which ripened them, affords to us the number of degrees answerable to their constituent parts: the investigation of barley, in like manner, though less important to our purpose, yet may, with some propriety, be admitted.