* ^ Gassy ^^ Curds. 195 



These fermentations usually begin during the cook- 

 ing process, and continue through cheddaring. Or- 

 dinarily they evolve a considerable amount of gas, 

 causing what are known as floating or gassy curds, 

 and are usually accompanied by disagreeable odors 

 and flavors. The formation of the gas in the curd 

 gives it a sponge -like texture, and when the par- 

 ticles of curd are cut across they are seen to be 

 full of minute holes, the condition usually denom- 

 inated pin-holes. The best means of treating this 

 trouble is, of course, prevention; but even with the 

 utmost care by makers of experience, milk contain- 

 ing the germs of these fermentations will find its 

 way into the vat. 



In many cases the trouble from gassy and tainted 

 milk is caused by the milk of one or two dairies, 

 and in exceptional cases the milk of a siagle cow 

 may infect a whole vat. The particular dairies or 

 even cows that are causing the trouble may usually be 

 detected by employing one of the fermentation tests 

 described in Appendix A. Ordinarily these fermenta- 

 tions do not work with the lactic fermentation ; each 

 hinders the action of the other so that the chief 

 means of overcoming the difficulty of gas or pin-hole 

 curds is to favor in every way possible the pro- 

 duction of lactic acid. To this end the milk is 

 well ripened before the rennet is added, and the 

 heat is raised as rapidly as possible to a higher 

 temperature of cooking than ordinarily is used. In 

 extreme cases the curds may be heated as high 

 as 104° F. After the whey has been drawn great 



