342 MISSOURI AGRICULTURAL REPORT. 



The common bitter taste is due to an abnormal fermentation. It is 

 generally understood now bv dairvmen that the sourinsr of milk or 

 cream is due to a formation of acid made from parts of the milk by the 

 action of little yeast-like bodies called bacteria. The bitter taste is pro- 

 duced by bacteria also, but by another kind than the ones which sour 

 milk. To produce the desired flavor in butter we want the cream to 

 sour with a clean, sour taste, and in fact want to keep everything else 

 in the way of bacteria out as much as possible. To get the cream to 

 sour as much as we wish, we want to furnish the bacteria which do this 

 and keep out the bad bacteria as the bitter producing kinds. We also 

 want to handle our cream to prevent as far as possible those that may 

 get in from doing any harm. 



The bacteria which produce the bitter products, we find, are gener- 

 ally in hay dust and stable dirt, and some always find their way into 

 milk, especially when the cows are in the barn. This is one of the two 

 reasons why the bitter taste is more apt to be found in winter-made but- 

 ter than in summer. The second reason, and the one having the most 

 influence, is that cream in winter, in a small dairy especially, is often 

 kept for a long time between churnings and at a rather low temperature. 

 These bitter products will seldom if ever be developed in cream or milk 

 kept at a temperature of 70 degrees or 75 degrees, as it will then sour 

 but not become bitter, although it may become rancid if kept too long 

 at that temperature. These bitter producing bacteria cannot work in the 

 presence of any amount of acid or sourness. As soon as the souring 

 begins the bitter product is not made any more. Butter does not gen- 

 erally become bitter for this reason, and the rapid souring of cream in 

 summer is largely what prevents it getting bitter at that season. The 

 bacteria which produce the bitter taste work best at a temperature so 

 low the milk will sour very slowly. 



The butter maker has the means of prevention always at hand. The 

 first thing to do is to use a good sour-starter in the cream at once after 

 separation, to start souring and check the other fermentations. Every 

 butter maker who expects to make a high grade of uniform butter should 

 make constant use of a goo.d starter. The other point is to keep the 

 temperature up until souring begins, and then cool, if necessary, to hold 

 a day or two. Sour first and the bitter bacteria will not work, even if 

 the cream be then kept cool a couple of days. Keeping cream over at 

 a temperature of fifty to sixty degrees and later warming for souring 

 is the condition that allows development of the bitter defect. 



