472 



BREWING. 



Brewing, tic fermentation either wholly or partially, before it 

 t y- 1 ^'' has sufficiently precipitated the mucilage, or, in the 

 language of the brewer, purged itself, and consequent- 

 ly it has an unpalatabL- mixture of acid from the ex- 

 cessive fermentation, and of bitter from the redundant 

 mucilage. In the other excess, that is, too low a 

 heat for the fermentation, the decomposition of the 

 wort takes place ; but this, not being succeeded by 

 the proper reunion of the parts, produces an unpala- 

 table half fermented liquor, containing a combination 

 of sweet spirit and bitter, and sometimes an approach 

 to putridity. The medium is to be sought for be- 

 tween 80 and 40 degrees of the thermometer ; the 

 exact temperature varying with the circumstances of 

 the preceding operations, the temperature of the 

 atmosphere, and the liquor which is intended to be 

 produced. In some of these (as in strong pale ales), 

 the object of the brewer is to form a beer of the 

 greatest possible strength and spirit, very clear and 

 fluid, of a fine light colour, without containing much 

 of the vegetable flavour. Such liquor approaches to 

 wine. In the other extreme, as brown ales and por- 

 ter, a fullness of palate, deep colour, glutinous taste, 

 and vegetable flavour, are produced, by retaining part 

 of the farinaceous matter, and giving to it an agreeable 

 taste by the fermentation, rather than expelling it 

 totally, as in the first instance. In making the re- 

 quired varieties, in the manner of the fermentation, to 

 meet these intentions of the brewer, the quantity and 

 0f yeasts, quality of the yeast employed, as well as the temper- 

 ature, must be considered. The yeast produced 

 from the fermentation of strong beer, is the most 

 proper to effect that temperate and regular fermen- 

 tation of the beer, which is described ; perhaps, from 

 the tenacity of its substance, it does not so suddenly 

 communicate the gas it contains, to the fluid which 

 it is intended to put in fermentation. The yeast of 

 weak small beers should not be used, when the other 

 can be procured ; for, though its fermentable powers 

 are slight, it is apt to act violently for a short time, 

 and then cease, probably from the thin light muci- 

 lage, of which the gas bubbles are formed, bursting as 

 soon as they are put in, and communicating their 

 contents to the wort. 



When the heat of the atmosphere is more than CO 

 degrees, the cool of the night must be chosen to put 

 the wort to work. In lower degrees of the atmo- 

 sphere, the wort must be set at a greater heat than 

 that of the air ; for, as the tendency to fermentation 

 increases with the heat of the weather, it is necessary 

 to correct this tendency, by putting the liquor to 

 work colder in hot weather, and hotter in cold wea- 

 ther. If the air is at 30 of Fahrenheit, small beer 

 should be pitched or set to work at about 70 ; beer 

 intended for keeping, at 56 ; and amber, or glutinous 

 ales, at 54. When the air is at 50, all these kinds 

 of beer may be set to work at 50. In the process 

 of fermentation, the temperature of the wort is often 

 increased as much as 10 ; and it may in general be 

 considered, that the wort will be 10 higher at the 

 height of the fermentation than it was when first put 

 to work, supposing the heat of the air continues the 

 same. 



The quantity of the yeast has some effect on the 

 degree of the fermentation : a greater quantity will 



fermenting 

 heats. 



Proportion 

 f yeasts. 



increase the rapidity of the process, in the same man- 

 ner as a greater degree of heat would, and vice rcr.iti; 

 hence a greater proportion of yeast is required in 

 winter than in summer. The quantity which will be 

 required at 80, will be only one-half of that requisite 

 to produce the same effects at 40. Small beer, not 

 intended for keeping, when the temperature is as low 

 as 40, will require about eight pints of yeast to the 

 extract of one quarter of malt ; at 60 six pints ; 

 and at 80 only four points. 



Beer intended to be kept ten or twelre months 

 will not require so large a proportion. Six pints at 

 40, five pints at 60, and three pints at 80, will be 

 found sufficient. The fermentation in the gyle tun 

 having advanced to that state when the head begins 

 to decline, shews that the vinous fermentation is ended. 

 If the beer is not cleansed just at this period, it will 

 become yeast bitter, which gives it an unpleasant 

 flavour, probably from the grosser parts of the yeast 

 being absorbed again in the liquor. The time when 

 these signs will appear varies with the fermenting heat. 

 At 60 it will sometimes require forty hours for the 

 fermentation, though at a greater heat twenty or 

 twenty-four are enough. The liquor is now possess- 

 ed of some spirit, but is still unpalatable, from the 

 mixture of extraneous farinaceous matter ; the wort 

 having parted with nothing in the fermentation but 

 carbonic acid gas. Though the mucilage of the yeast 

 is thrown up in part, it returns again ; but the mode 

 of its existence is changed, from the chemical solu- 

 tion it had in the wort, to mechanical mixture : At 

 least this change is partially effected, as is shewn by 

 the turbid appearance of the liquor. If the beer 

 were suffered to remain in the gyle tun, the acetous 

 fermentation would take place, the spirit or alcohol 

 at one time visible in the beer would be lost, and 

 acidity produced. After the acetous fermentation, 

 the beer, under certain circumstances, would produce 

 vinegar, but not in general, for the wort intended 

 for beer has too much of the farina of the malt ex- 

 tracted in the mashing ; and the addition of the hops, 

 if in sufficient quantity, will totally prevent it from 

 becoming good vinegar, though it may acquire too 

 much acidity to be drunk, and at the same time bit- 

 ter, and perhaps putrid in some degree, from, the 

 early decomposition of some of its constituent parts ; 

 for the acetous fermentation is followed by the pu- 

 trefactive, which effects a total decomposition of the 

 beer, leaving a putrid disorganized liquor, unfit fot 

 any purpose. 



SECT. VII. Of Cleansing. 



The object of cleansing is to stop the fermenta- 

 tion at the proper period, which is effected by draw- 

 ing off the beer into smaller vessels, usually small 

 casks. This lowers the temperature ; for, as the 

 action of fermentation produces an internal heat in 

 the liquor, it follows, that this heat will be diminish- 

 ed by dividing it into smaller quantities, when, by 

 the casks exposing a greater surface to the external 

 air, the heat is allowed to escape. Notwithstanding 

 the diminished heat, the disturbance of the beer re- 

 news the fermentation, probably by incorporating 



Criteri 



of fc-rn 

 union. 



Ue o 

 cleans 



