UTENSILS NECESSARY IN THE PREPARATION OF CHEESE. 217 



greater pressure. In this case it is recommended to substitute a 

 wooden vat with a metal casing which is provided with a bad heat 

 conductor a covering of wood, or a wooden jacket (fig. 61). 



The necessary size of the water kettle for supplying steam is easily 

 ascertained, if it be remembered that water converted into steam at 100 C., 

 and under an atmospheric pressure of 760 mms., takes up approximately 

 537 heat units, and that saturated steam when it is condensed into water 

 gives off the same quantity of heat. For example, if 1500 kilos. (328 

 gallons) of milk is the largest quantity which it is desired to heat at one 

 time from 10 to 35 C., that is, to increase the temperature about 25, 

 37,500 heat units will be required, taking the specific heat of milk to be 

 equal to that of water. Every kilo, of steam yields, when perfectly con- 

 densed, at 100 C. 537 units, and when water is cooled to 35 C. 65 more 

 units, altogether 602 units of heat. As 602 goes into 37,500 exactly 

 62-29 times, there must be used in the vat, if no loss is to take place, 

 about 63 kilos, of water, that is, 63 kilos, of water must be converted into 

 steam. With regard to the unavoidable losses, especially with reference 

 to the fact that it is very convenient to utilize the hot water in the kettle 

 as may be desired for any purpose, the size of the kettle should be double 

 what is necessary, at least, that is to say, of such a size that it will contain 

 126 kilos, or more. 



A good arrangement for the heating of a cheese-kettle with steam has 

 many other advantages as contrasted with the heating over an open fire. 

 Apart from the fact that it renders all operations which have to be carried 

 out in the kettle distinctly easier, it is simpler, more cleanly, distinctly 

 cheaper, since in addition to wood, turf, and peat, coal, brown -coal, or 

 coke may be used, and it allows larger quantities of hot water to be 

 prepared every time, and at the same time may be used for heating the 

 dairy rooms with steam or hot water. 



The large American cheese-vats are 

 made out of tinned copper, white-metal, or 

 tin, and are heated usually with hot water, 

 occasionally, however, with steam. The 

 most largely used in America is the Oneida 

 cheese- vat (fig. 62). The other vats which 

 are in common use are Armstrongs, Mil- 

 ler's, Jones's, Falkner Stuart's, Seeger's, 

 and others (fig. 63). During the second half of the seventies, the 

 experiment was made of introducing the American cheese- vats into 

 Germany, which was assuredly not in the interests of German 



