92 



THE PART PLAYED BY HOP TANNIN 

 IN BREWING. 



T^HE tannin, or tannic acid, of hops formerly had a considerable 

 reputation as an important contributor to the soundness of 

 the wort ; for GRIESSMEYER, having observed that the ordinary 

 tannin of commerce, or gallo-tannic acid as it is frequently called, 

 precipitated albuminoid matter from wort, concluded that the hop 

 tannin had the same effect, and that such nitrogenous matter 

 having been removed the ultimate beer would be by so much the 

 sounder. This led to the use of tannin in the copper, and to this 

 day in certain breweries there exist small pipes connecting the 

 copper with the brewing room, which formerly served to convey 

 the solution of tannic acid to the boiling wort at the proper time ; 

 and some brewers have not yet given up the addition of a small 

 quantity of catechu (which contains about 50 per cent, of tannin) 

 to the copper as a matter of routine. 



Later work has conclusively proved that the amount of 

 nitrogenous matter precipitated by the hop tannin is not only 

 insignificant, but that no connection has been proved to exist 

 between the percentage of nitrogen in beer and its stability. In 

 this respect some of BRIANT and MEACHAM'S work on hops may be 

 quoted. In a paper published in 1894 (Institute of Brewing, Vol. VII, 

 p. 132) they give particulars of experiments made on the amount 

 of nitrogenous matter precipitated from a wort by hops. A volume 

 of wort running bright from the mash -tun was taken and carefully 

 filtered at 150 F., and the nitrogen in it was then determined by 

 KJELDAHL'S method ; then two volumes of 500 c.c. each of this were 

 taken and boiled for one hour, one being hopped at the rate of 



