236 SCIENCE AND PRACTICE OF DAIRYING. 



118. The Eipening of Cheese. The chief constituent of all fresh 

 cheese the paracasein is only very slightly soluble in water. It is 

 on this account that fresh cheese, unless it be in a perfectly soft, 

 almost gelatinous or buttery condition, is not enjoyable or palatable. 

 In order to render it palatable, it is allowed to ripen, that is, 

 it is kept under suitable conditions ( 116) till decomposition of 

 its constituents, which takes place as soon as the bacteria present 

 in the cheese mass are cultivated and developed, is permitted to go 

 on for a certain time. When this limit is reached the cheese is 

 known as ripe. Ripe cheeses of any kind, which have been kept 

 for just the proper length of time, possess the best flavour and the 

 highest value which the kind of cheese can attain to. 



The most important process, in the ripening of cheese, is the 

 change which the paracasein undergoes. From this chief constituent 

 of the cheese simple compounds are formed, which are soluble in 

 water; then compounds which resemble, and which are akin to the 

 albuminoids. Among these, peptone, probably also caseo-glutin, 

 subsequent numerous further products of decomposition, among 

 which are amido acids, phenol-amido proprionic acid, and leucin and 

 tyrosin, have been identified, and finally ammonia salts. The soluble 

 bodies which are held in the water present in the cheese, determine 

 by their quantity and condition the flavour of the cheese, and alter 

 the appearance and consistency of the cheese mass by penetrating 

 through its pores. 



Milk-sugar, which is only present in fresh cheeses to a small 

 extent, quickly vanishes under all conditions. It is either entirely 

 converted into lactic acid, from which further decomposition pro- 

 ducts for example, butyric acid may be formed, or it is changed 

 into a form of fermentable sugar, and then gives rise to a remarkable 

 fermentation, accompanied with development of gas. This fermenta- 

 tion is effected by bacteria, and yields, in addition to small quantities 

 of alcohol and other substances regarding which we know nothing, 

 chiefly carbonic acid, which is produced in large quantities, and 

 hydrogen. With regard to this interesting phenomenon, as well as 

 with regard to the formation of bubbles in the cheese, investigations 

 are at present being carried out, which will doubtless very soon furnish 

 more exact information. In what way the conversion of milk-sugar 

 and its products influences the other processes of decomposition 

 taking place in the cheese mass, or acts upon the digestibility and 

 the condition of the cheese mass, or the flavour of the cheese, we 



