238 Testing Milk and Its Products. 



pressure gauge, and a thermometer. The oven used 

 by Professor Dean of Guelph (Ont.) Dairy School, the 

 originator of this method, was 6x8 inches. It was made 

 of galvanized iron by a local tin-smith at a cost of 

 about $5.00, exclusive of safety valve and steam gauge, 

 and was made to withstand a pressure of about 10 

 pounds. After iive or six hours' drying in the oven, 

 the samples of butter are ready to be weighed, and the 

 loss gives the amount of water present therein. The 

 average results obtained by this method with nine sam- 

 ples of butter came within .13 per cent, of those found 

 by chemical analyses. 



The same method is recommended by the author for 

 determining the per cent, of water in curd or cheese. 



277. The Wisconsin high-pressure oven method 

 (see fig. 61). Either 10 or 50 grams of butter are 

 weighed in a flat-bottomed tin or aluminum dish. This 

 is placed in an oven heated by high pressure steam to a 

 temperature of 240° to 280° F. The length of time re- 

 quired to expel all the water from the butter will de- 

 pend on the temperature of the oven and the diameter 

 of the dish in which the butter is heated. If the dish 

 is large enough to permit the butter to spread into 

 a very thin layer and the temperature of the oven 

 reaches 260° F., the water will be completely expelled 

 in half an hour. Ovens of this construction have now 

 been placed on the market by manufacturers of dairy 

 supplies. A steam pressure of 60 lbs. and a tempera- 

 ture of 280° F. may be obtained in such an oven; by 

 employing the boiler pressure ordinarily used in a 



