548 FRA QMKNT8 F SCIENCE. 



and a flavor peculiar to itself. Keep them out of your 

 beer and it remains forever unaltered. Never without 

 them will your beer contract disease. But their germs are 

 in the air, in the vessels employed in the brewery; even in 

 the yeast used to impregnate the wort. Consciously or 

 unconsciously, the art of the brewer is directed against 

 them. His aim is to paralyze, if he cannot annihilate 

 them. 



For beer, moreover, the question of temperature is one 

 of supreme importance; indeed, the recognized influence 

 of temperature is causing on the continent of Europe a 

 complete revolution in the manufacture of beer. When I 

 was a student in Berlin, in 1851, there were certain places 

 specially devoted to the sale of Bavarian beer, which was 

 then making its way into public favor. This beer is pre- 

 pared by what is called the process of low fermentation; 

 the name being given partly because the yeast of the beer, 

 instead of rising to the top and issuing through the bung- 

 hole, falls to the bottom of the cask; but partly, also, 

 because it is produced at a low temperature. The other 

 and older process, called liigli fermentation, is far more 

 handy, expeditious, and cheap. In high fermentation 

 eight days suffice for the production of the beer; in low 

 fermentation, ten, fifteen, even twenty days are found 

 necessary. Vast quantities of ice, moreover, are consumed 

 in the process of low fermentation. In the single brewery 

 of Dreher, of Vienna, a hundred million pounds of ice are 

 consumed annually in cooling the wort and beer. Not- 

 withstanding these obvious and weighty drawbacks, the 

 low fermentation is rapidly displacing the high upon the 

 Continent. Here are some statistics which show the 

 number of breweries of both kinds existing in Bohemia 

 in 1860, 1865, and 1870: 



I860. 1865. 18TO. 



High Fermentation . . 281 81 18 



Low Fermentation . .135 459 831 



Thus in ten years the number of high-fermentation 

 breweries fell from 281 to 18, while the number of low- 

 fermentation breweries rose from 135 to 831. The sole 

 reason for this vast change a change which involves a 

 great expenditure of time, labor, and money is the 

 additional command which it gives the brewer over the 



