Skimmed-milk as it comes from the separator is at a temperature of about 88° to 90° F.; it is ripened and set at this temperature. It is ripened rather highly on the acid test, from 0.18 to 0.20 of 1 per cent, and to correspond on the rennet test which will not be many spaces. In about twenty-five to thirty minutes it is coagulated ready for cutting. The curd of skimmed-milk cheese is cut a little softer than is that of whole-milk cheese. Milk is usually set at 88° to 90° F. The curd is not ordinarily cooked above this temperature. If the milk was 84° to 86° F. when set, then the curd should be raised to 88° to 90° F. The curd firms in the whey very rapidly. When firm enough, it should have a slight development of acid. On the acid test it should show 0.17 to 0.19 per cent, and on the hot iron 1/8 to ¼ of an inch. The milk should be ripe enough or starter enough should have been used, so that the acid will continue to develop in the "pack" very rapidly. During the cheddaring process the curd is piled more rapidly and in higher piles than is customary with whole-milk cheese. This is necessary to incorporate or assimilate a large percentage of water or whey in the cheese. Therefore the process of skimmed-milk Cheddar cheese is much shorter. More acid is developed with the skimmed-milk than with the whole-milk cheese because it seems necessary to develop proper texture. If the acid is not developed sufficiently, the cheese will be very rubbery and cure very slowly, in which case bad fermentation and flavor may and often do develop. The curd is turned, piled or cheddared in the vat until it begins to become meaty and fibrous. If there is danger of too much acid, the curd may be rinsed off with water. It is then milled and salted at the rate of 1 or 1¼ pounds of salt to the curd from each 1000 pounds of milk. The remainder of the process is the same as that for making whole-milk cheese.