Whatever vegetables wines are produced from, whenever they deviate from the respective perfection, a well-conducted fermentation might have made them arrive at, they may be said to be distempered. Foulness, or want of transparency, is not the least evil, but, according to its degree, it obtains various appellations, and requires different helps. From what has been said, nothing can be more plain, than that it is always in our power to form beers and ales, which will be bright. Yet porter or brown beer is constantly so brewed as to need precipitation: the reasons for this management have before been offered. Were we to wait till the liquor became transparent by age, a more real disorder would ensue, that of acidity. Precipitation is then serviceable, especially when beers are to be removed from one cellar to another, a short space of time before they are to be used. By being shook, and the lees mixed with the liquor, a strong acid taste is conveyed therein, and the power of subsiding, which is wanted, renders the forcing them, in that case, of absolute necessity. In beers brewed with liquors sufficiently heated, no flatness is occasioned thereby; as the case is, under like circumstances, with liquors produced by low extracts, from grain not sufficiently dried. The degree of foulness in porter should however be limited; its bounds ought not to exceed the power of one gallon of dissolved isinglass, to a butt. Isinglass is dissolved in stale beer, and strained through a sieve, so as to be of the consistence of a jelly. The beer is set in motion with a stick, which reaches one third part down the cask, before and after this jelly is put in; and a few hours should be sufficient to obtain the desired effect. We have before observed, that this quantity of jelly of isinglass is equal to a medium of 10 degrees dryness in the malt, and heat of the extracts. When the opacity exceeds this, the liquor is termed _stubborn_; the same quantity of dissolved isinglass repeated, is often sufficient, if not, six ounces of the oil of vitriol are mixed with it. An effervescence is, by this addition, produced; the oils of the drink become more attenuated, and the weight added to the precipitating matter, is a means to render it more efficacious. Instead of the oil of vitriol, six or eight ounces of the concrete of vitriol, pounded and mixed with the isinglass, are sometimes used with success. A foulness in beer beyond that which is called _stubborn_, gives to the drink the denomination of _grey beer_. This arises from the oils which float upon the surface, and which the liquor has not been able to absorb. In this case, the same methods as before mentioned are repeated; the quantity of dissolved isinglass is often increased to three gallons, that of vitriol to more than 12 ounces, and sometimes a small quantity of _aqua fortis_ is added to these ingredients.