DAIRYING 61 



They are a'll made with the same object in view that is to protect 

 the cream from the surrounding air temperatures and to change 

 the temperature of the cream as desired. 



509. The Channel Bottom Open Vat is the oldest cream 

 ripening-vat in common use. A space of several inches between 

 the tin and the wood sides of the vat is rilled with water, and in 

 some of them an ice box is built at one end. In this vat the cream 

 must be stirred by hand with a tin dipper or a wooden stirrer when 

 the butter maker wishes to change the cream temperature. On 



Plate 15---The Boyd Cream Ripener 



account of the small porportion of the cream touching the tin sides 

 of these vats, changes in temperature are made rather slowly when 

 large quantities are ripened at one time. These vats have been 

 used extensively in the past, and many dairies and creameries are 

 fitted up with them, as no other vats were proposed for a number 

 of years. 



510. The Twin Cream Vat is made on the same plan as the 

 open vats, except that it is composed of two long narrow tin vats 

 placed inside one wooden box. Both the vats are surrounded by the 

 same water and must consequently be held at the same tern- 



