16 



FERMENTING POWER OF PURE YEASTS. 



of different quantities of yeast upon rapidity of fermentation. The 

 M wings were made in a filtered and sterilized grape must of the 

 approximate analysis shown in Table II. Three flasks containing 

 400 cc each of the sterilized grape juice were sown as follows: No. 1 

 with 1 drop on standard loop ; No. 2 with 1 cc taken up in a pipette ; 

 No. 3 with 10 cc taken up in a pipette. ' 



TABLE II. Partial analysis of j/r<ijie must used in the experiment and the 

 liquor after fermentation. 



[Grams per 100 cc.] 



Steinberg yeast was used, the same as is denominated No. 53 in the 

 descriptive list on page 25. The flasks were all kept in the culture 

 oven, but the gas lamp was turned off at night. The temperature, 

 though not maintained at the most desirable degree, was fairly con- 

 stant, approximating 21 C., but with extremes of 19 C. to 25 C. 

 The time covered by the entire experiment was twenty- four days, but 

 the curves on the chart (fig. 3) are given for only twelve days, the 

 later fermentation having little interest in this discussion. The dia- 

 gram shows that No. 3, which received the largest amount of yeast, 

 made a very rapid fermentation the second and third day, reaching 

 the climax on the fourth day. This should certainly result when, as 

 in this case, the quantity of culture used as a starter is as 1 to 40 of 

 the must. No. 2, which received 1 to 400 parts of culture, exceeds in 

 activity for the fourth day the heavy sowing of No. 3. This illustrates 

 forcibly the point shown in all of this work, namely, that a small pro- 

 portional inoculation with the pure culture answers every purpose, 1 

 part to 400 being sufficient under good conditions. The validity of 

 this observation is borne out by flask No. 1, which received a compar- 

 atively infinitesimal sowing of 1 drop to 400 cc of must, yet, when 

 LTowtli fjiirly started on the third day, it rushed to a point compara- 

 tively high on the fourth day, and reached its climax on the fifth day. 



The prompt control which can be obtained by a heavy sowing of 

 yeast when there is pressing need of securing a dominant iVnncntat ion 

 to guard against unfavorable conditions is most simply illustrated in 

 this case by the prompt manner in which No. 3 started. 



