206 " DISEASES " OF BEER, 



since then has been employed on a large scale in Scan- 

 dinavian breweries. Amongst the other yeasts present, I 

 found the species which I have named Sacch. Pastorianus I. 

 It was only when this species was present in the pitching yeast 

 that the disease occurred. However convincing such laboratory 

 experiments may be, they do not carry the same demonstra- 

 tive force as trials made in the brewery itself, and under the 

 conditions obtaining in practice ; in the following, only experi- 

 ments of this nature will, therefore, be described. 



I. Series of Experiments. Three of the above-mentioned small fer- 

 menting vessels, C, D, E, were charged in the fermenting cellar of the Old 

 Carlsberg brewery with ii hectoliters of ordinary aerated wort of 13*3 

 per cent. Balling. The temperature of the wort at pitching was 7 ' 8 C., 

 that of the fermenting cellar 5-6 C. 



C was pitched with 500 grams of Sacch. Pastorianus I. 



D 400 Carlsberg bottom yeast No. I, 



and 100 grams of Sacch. Pastorianus I. 



E 500 grams of Carlsberg bottom yeast No. i. 



The yeast was of a thick consistency in all cases, and was grown in 

 similar wort at 8-10 C. After eleven days the extract was found to be 

 6 '03 per cent. Balling in C, 5 '54 per cent, in D, and 6*27 per cent, in E. 

 The beer from each vessel was then drawn off into three small casks, and 

 . these were placed in the lager cellar at a temperature of 2-3 C. The 

 beers from C and D had an objectionable odour and a bitter disagreeable 

 taste, whilst that from E had a satisfactory taste and odour ; the bitter 

 taste was strongest in C. Although a vigorous fermentation had taken 

 place, the beer from C and D clarified badly, that from E, on the other 

 hand, was faultless. 



After being stored for about a month, samples from one series of the 

 casks were drawn off into colourless glass bottles. C was quite cloudy, D 

 was nearly bright, and E was perfectly bright. After standing for five 

 days, at the ordinary room-temperature, D showed a slight yeast turbidity, 

 whilst E showed no signs of cloudiness after twelve days. In the case of 

 the beer which had been fermented partly with Sacch. Pastorianus /. 

 the disagreeable taste and odour were very marked, whilst the beer 

 which had been fermented with Carlsberg bottom yeast No. I alone, 

 possessed the same good taste and odour as the ordinary lager beer of 

 Old Carlsberg, After the beer had been a little more than two months 

 in the lager cellar, D and E were perfectly bright, while C was still 

 cloudy. The extract was 5 54 per cent. Balling in C, 5 37 per cent, in D, 

 and 5 * 29 per cent, in E. With regard to taste and odour, there was the 

 same difference as before. The beer from D had now also become stable 



