82 VERMONT DAIRYMEN'S REPORT. 



a common practice to churn the cream sweet or even to churn 

 the milk, but it was found that such butter lacked the keeping 

 quality and aroma found in butter made from ripened or slightly 

 soured cream. Working on this principle the process of ripen- 

 ing cream has to-day become an art and the most successful 

 butter-maker is the one who most thoroughly understands how 

 to control this process properly. With the advent of the cen- 

 trifugal cream separator the process was more easily controlled, 

 since it gives the butter-maker cream directly from the milk 

 without its aging, so that the fermentation is under his control 

 from the start. There are many creameries to-day, however, 

 that are working under the disadvantage of gathered cream 

 systems where the cream is collected from the farmers either 

 daily or every other day. In this case oftentimes the cream is 

 all ready ripened or is over-ripe before the butter-maker gets 

 it, thus making it impossible for him to turn out a first-class pro- 

 duct. The amount of acid developed in cream during the rip- 

 ening process is important, too little rendering the butter of 

 poor keeping quality and flavor, while an excess tends to pro- 

 duce a butter that turns rancid quickly. Butter-makers have 

 found that about 0.5 per cent lactic acid in the cream develops 

 the best aroma together with the desired keeping quality. It 

 is the custom in some creameries to use a so-called starter for 

 the cream, and one of the common forms of such starter is 

 made by saving out a portion of milk from a particularly neat 

 farmer, letting it sour by itself and then adding this as a sort of 

 leaven to the fresh cream. Others have found that this process 

 is on the whole is a good practice, yet sometimes it fails 

 them, and so consequently have adopted a commercial pure 

 culture of bacteria that has been selected for that purpose. 

 Dr. V. Storch of Copenhagen, Denmark was the pioneer in 

 using pure cultures. Believing that acid producing bacteria 

 were the cause of ripening he selected 'from ripened cream 

 such cultures as seemed desirable and used them for seeding 

 cream to produce the correct fermentation. Later Dr. Weig- 

 mann of Germany, worked along similar lines and isolated 

 several cultures which are now to be had in a powder form and 

 are used in the same way as the Storch culture, Some three 

 years ago I became interested in the subject of cream ripening 

 and isolated a form of bacteria which seems to have given bet- 

 ter results than any of the foreign cultures we have tried. This 

 culture is distinct from the acid bacteria variety of Storch and 

 Weigmann, and is intended to be used for flavor production 

 alone, the necessary acid being developed from the naturally 

 contained lactic acid bacteria of milk. I have refrained from 

 putting up our culture in any way different from that first 

 adopted by me in 1893, which is to introduce the culture 



