STUDIES ON FERMENTATION. 391 



been obtained by working on this system, there is no doubt that 

 it would possess keeping qualities far superior to those of beer 

 made with ordinary yeast, even supposing that beer to have 

 been treated with every possible precaution, and to be as pure 

 as any produced in the best regulated breweries. 



In the month of September, 1874, we conducted an experi- 

 ment at Tantonville, in a closed vessel capable of holding 6 

 hectolitres (132 gallons). The deposit of yeast served to pitch 

 an open vessel, the wort of which had, moreover, been cooled 

 under conditions of purity. The cooling bad been effected by 

 means of the Baudelot refrigerator, represented in Fig. 85, the 

 wort in the closed vessel having been similarly'' treated. For 

 shortness sake, we may designate the closed vessel and its beer 

 by the letter K, and use the letter M for the open vessel and its 

 beer, and T for the corresponding beer of the brewery. The 

 vessel K was pitched on September 4th, and racked on Sep- 

 tember 17th, the beer then showing a density of S'S"" Balling. 



The beers K and M were sent to Paris at the same time as 

 some barrels of the beer T, brewed by the ordinary process ; 

 and samples of these different beers, which arrived on October 

 22nd, were procured from five different cafes for purposes of 

 examination. 



The beer M did not suffer by comparison with the beer T. 

 The similarity between the flavours of these two was so close as 

 to puzzle even experienced judges. In both cases the beer was 

 brilliantly clear. In two cafes the beer M was even preferred 

 to T, being considered softer on the palate {moellense) and of 

 more decided character [corsee) than T, a circumstance which 

 may be explained by the fact that its wort had been less 

 aerated. 



The beer K, although very clear and bright, was considered 

 inferior to M, but the sole reason of this was that at the date 

 when it was tasted — November 3rd — it did not froth. As we 

 have already remarked, a peculiarity of the beers made in closed 

 vessels is that their secondary fermentation takes a longer time 

 to develop. The yeast held in suspension in the beer, at the 



