BEEE 303 



alluded to as the farina or pollen of tho hop, which in good samples will amount to 

 one-sixth of their weight. This powder bears some resemblance to lycopodium ; and 

 its analysis by Dr. Ivos gives, tannin, 4'16 ; extractive, 8'33 ; bitter principle, 9'16 ; 

 wax, 10-00 : resin, 30'00 ; lignin, 38'33 ; and loss, 0-02. About 65 per cent, of the 

 farina is soluble in alcohol, and the solution, distilled with water, leaves a resin 

 amounting to 52'5 per cent., which has no bitter taste, and is soluble in alcohol or 

 other. The distillate from which tho resin has thus been separated contains the 

 bitter principle, which has been called lupuline (by Payen and Chevallior), mixed 

 with a little tannin and malic acid. 



To obtain this in a state of purity, the free acid must bo saturated with lime, the 

 solution evaporated to dryness, and the residuum treated with ether, which removes 

 a little resin ; after which the lupuline is dissolved out by alcohol, leaving the malate 

 of lime. On evaporating tho alcohol, the lupulino remains, weighing from 8 '3 to 12*5 

 per cent. It is sometimes -white, or slightly yellowish, and opaque, sometimes orange- 

 yellow and transparent. 



At ordinary temperatures it is inodorous, but when heated omits the peculiar smell 

 and possesses the characteristic taste and bitterness of tho hop. Water dissolves it in 

 the proportion of about 1 part to 20, or 5 per cent., and acquires a yellow colour. It 

 is quite soluble in alcohol and slightly so in ether. 



Lupuline is neither acid nor alkaline, nor is it acted upon by solutions of tho metallic 

 salts ; it contains only a small quantity of nitrogen, and an essential oil. 



Tho analysis by Payen and Chevallier gives tho following : Volatile oil, 2'00 ; 

 lupuline, 10'30 ; resin, 55-00; lignin, 32-00; loss, 0-70. There are also traces of 

 fatty, astringent, and gummy matters, malic and carbonic acids, and various salts. 



The volatile oil was procured by Dr. Wagner by distilling fresh hops with water. 

 It constituted about 8 per cent, of the air-dried flowers, it possessed a clear brownish- 

 yellow colour, had an acrid taste and a strong odour of the hop. Its specific gravity 

 is about 0-910 ; it is partially soluble in water, but more so in alcohol and ether, and 

 becomes resinified by keeping. The tannin of the hop is also important in brewing, 

 ns it serves to precipitate the nitrogenisod or albuminous matter of the barley, and 

 assist the clearing of tho liquor. Ivos thought the scales of tho hop, when freed 

 from the yellow powder, contained no principles analogous to it; but it is almost 

 impossible to free them entirely from tho lupulinic grains ; and Payen and Cheval- 

 lier found the same principles in the different parts of tho hop, but in different 

 proportions. 



2, THE PREPARATION OP THE BAULKY BY THE PROCESS OF MALTING. 



In this process (for the conduct of which we refer to tho article MALTING) 

 the raw grain is steeped in cisterns of water until it has imbibed sufficient to cause 

 it to germinate ; it is then spread on the floor of the malt-house, and frequently 

 turned, until the germination has advanced to the stage when tho plumula is about to 

 make its appearance, and its further germination is stopped by being rapidly dried 

 on the malt-kiln. 



During germination a remarkable change has taken place in tho substance of tho 

 grain. The glutinous constituent has almost entirely disappeared, and is supposed to 

 have passed into the matter of tho radicles, or roots, which during the process will 

 have grown rapidly to nearly one and a half the length of the grain, while a portion 

 of tho starch is converted into sugar and mucilage. 



The change is similar to that which starch undergoes when dissolved in water and 

 digested in a heat of about 160 F. along with a little gluten. The thick paste be- 

 comes gradually liquid, transparent and sweet-tasted, and the solution contains now 

 sugar and gum, with some unaltered starch. Tho gluten suffers a change at the 

 same time, and becomes acescent, so that only a small quantity of starch can thus 

 be converted by a quantity of gluten. 



By the artificial growth upon the malt-floor all tho gluten and albumen present in 

 barley are not decomposed, and only about one-half of tho starch is converted into 

 sugar, as a continuance of the germination would exhaust the grain, and tho valuable 

 products would bo taken up by the growth of the roots and stems of the plant. It is, 

 therefore, tho chief art of the maltster to regulate the germination and stop it at the 

 point when the utmost conversion is attained with tho least loss. This is generally 

 considered to be done when the plumula, technically known as tho acrospirc, has 

 advanced two-thirds the entire length of the grain, Stirling from tho germ and pro- 

 ceeding under tho skin toward tho other end of the grain, beyond which it must never 

 bo suffered to protrude ; tho conversion of tho hordeinc into starch and sugar keeping 

 pace with tho growth of tho acrospirc, and being thus prepared for its nearly com- 

 plete conversion in the subsequent operations of the brewer. 



