BEER.

121

motion to the machine, has two level wheels, h i, fixed upon a tube, f g, which is, fittedupon a central shaft. These wheels actuate the wheels m and o, upon the end of thehorizontal shaft n n; hut the distance between the two wheels h and i is such, that theycannot-be engaged both at once with the wheels m and o; but the tube f g, to whichthey are fixed, is capable of sliding up and down on its central axis sufficiently to bringeither wheel h or i into gear with its corresponding wheel o or w, upon the horizontalshaft; and as the diameters of n o, and i 7n> are of very different proportions, the velocityot the motion of the machine can be varied at pleasure, by using one cr other. k andare two levers, which are forked at their extremities, and embrace collars at the endsthe tube f g. These levers being united by a rod, 7, the handle lc gives the means ofmoving the tube f g, and its wheels h i } up or down, to throw either the one or the otherwheel iqto gear.

. The object of boiling the wort is not merely evaporation and concentration, but extrac-tion, coagulation, and, finally, combination with the hops; purposes which are better ac-complished in a deep confined copper, by a moderate heat, than in an open shallow panWith a quick fire. The copper, being incased above in brickwork, retains its digestingtemperature much longer than the pan could do. The waste steam of the close kettle,moreover, can be economically employed in communicating heat to water or weak worts;whereas the exhalations from an open pan would prove a nuisance, and would need to becarried off by a hood. The boiling has a four-fold effect: 1. it concentrates the wort; 2.during the earlier stages of heating, it converts the starch into sugar, dextrine, and gum,by means of the diastase; 3. it extracts the substance of the hops diffused through thewort; 4. it coagulates the albuminous matter present in the grain, or precipitates ft bymeans of the tannin of the hops.

The degree of evaporation is regulated by the nature of the wort, and the quality ofme beer. Strong ale and stout for keeping, require more boiling than ordinary porterov table-beer brewed for immediate use. The proportion of the water carried off byevaporation is usually from a seventh to a sixth of the volume. The hops are introduceduring the progress of the ebullition. They serve to give the beer not only a bittermomatic taste, but also a keeping quality, or they counteract its natural tendency 1^ecome sour; an efi'ect partly due to the precipitation of the albumen and starch, byteir resinous and tanning constituents, and partly to the antifermentable properties ofhen lupuline, bitter principle, efhereous oil, and resin. In these respects, there is nonethe bitter plants which can be substituted for hops with advantage. For strong beer,Powerful fresh hops should be selected: for weaker beer, an older and weaker articleW, M suffice.

The hops are. either boiled with the whole body of the wort, or extracted with aPottiou of it; and this concentrated extract added to the rest. The stronger the hops- le ’ tb c longer time they require for extraction of their virtues; for strong hops, an hourda half or two hours boiling may be proper; for a wfeaker sort, half an hour or anlna y he sufficient; but it is never advisable to push this process too far, lest a dis-steeable bitterness, without aroma, be imparted to the beer. In our breweries, it is thei ractice to boil the hops with a part of the .vort, and to filter the decoction through a„ ainel i’ called the jack hop-back. The proportion of hops to malt is very various; but, inXOnTh ’ ^ 10In a pound and a quarter to a pound and a half of the former are taken forU lbs. of the latter in making good table-beer. For porter and strong ale, 2 pounds of

ps are used or even more; for instance, one pound of hops to a bushel of malt, if thePeer be ___r

he destined for the consumption of India .v . Ulln 3 the boiling of the two ingredients, much coagulated albuminous matter, inca l| 10 ! ls sta tes of combination, makes its appearance in the liquid, constituting what isiu it 4 ’Tn ^ rea ^ n S ur curdling of the wort , when numerous minute flocks are seen floating.su „ a , 1 jc resinous, bitter, and oily-ethereous principles of the hops combine with theshowirur h ® um -’ 01 dextrine of the wort; but for this effect they require time and heat;j\ _ || => “at the boil is not a process of mere evaporation, but one of chemical reaction.Wort ?' VISa '" re en pellicle of hop-oil and resin appears upon the surface of the boilingcomnlet t somew ^ at frothy form: when this disappears, the boiling is presumed to bePressed 6 ’ tbe beer * s s t ra i ne< i off into rte cooler. The residuary hops may beand J used for an inferior quality of beet; or they may be boiled with fresh wort,Fig. ,. 107 ins the next brewin S charge.

fig- 108 a f epresent tbe copper of a London brewery. Fig. 107 is a vertical section;Per kettle hav* »~^ an °*' tbe ® re_ S rate aa d flue, upon a smaller scale : a is the close cop-the upper'part'of’rt' 8 convex within; b is the open pan placed upon its top. From

during the cbuiYt’ C0 Pper, a wide tube, c, ascends, to carry off the steam generatedtobes^d d (two rm]° n ?*? ' wort ) which is conducted through four downwards-slantingWarm its contents^ ^ v * s * b ' e m this section), into the liquor of the pan b, in order to“ * ' -A vertical iron shaft or spindle, e, passes down through the tube c,

Pearly to the bottom

°f the copper, and is there mounted with an iron arm, called a