Cottage Cheese - Short Set (Emmons & Tuckey, 1967)
Manufacturing procedures may differ considerably and still yield a high-quality product. They differ chiefly in temperature of setting and in amounts of starter and rennet. Procedures differ also in the size of curd, creaming rates, type of cream, the degree of "cottage cheese flavour" and added condiments. With any procedure, though, it is vital that the cheese maker follow it carefully and consistently from day to day.
The short-set procedure is widely used chiefly because it can be carried out within one working day and the time in a vat is minimal. It can be considered as labour-saving because the approximate time for cutting may be predicted fairly closely and the cheese maker does not have to wait for the proper cutting time. Steps in this process are:
- Add 5% of starter to pasteurized skim milk at 32C. Stir well for 10-15 min.
- Add rennet at the rate of 3 ml per 1,000 kg of skim milk at the time the starter is added, or 1 to 1 Omega hours later. If the A-C test is used to determine the cutting time, take the A-C test sample before adding the rennet.
- Determine the cutting time using pH measurements of the curd, the A-C test or titratable acidity of the whey. Optimum values for pH at cutting depend on the heat treatment and composition (total solids) of the skim milk. Generally, pH of 4.80 in the curd can be used for normal skim milk when rennet is used. Use 1.2 cm (3/8") knives.
- After cutting, the curd is left undisturbed for 15 to 20 min while the water in the jacket is heated in preparation for cooking.
- Raise the temperature of the heating water at a rate such that the temperature in the vat rises 0.5C each 5 min for the first 30 min. After this , the rate may be doubled and eventually tripled until a final cooking temperature of 54 - 57C is reached about 2 hours later. Stirring should be gentle to prevent shattering, yet frequent enough to prevent matting. If both matting and shattering occur, the rate of heating is probably too fast.
- The proper firmness should be reached after holding 15 to 20 minutes at 54-57C. The curd should be checked frequently during cooking to ensure that it does not become too firm. The pH or acidity at cutting is the chief factor influencing the firmness of curd at the final cooking temperature. If curd is consistently too firm at 54-57C, the cutting acidity should be raised, or the cutting pH should be lowered slightly. If curd is consistently too soft at 54-57C, the cutting acidity should be lowered, or the cutting pH should be raised slightly. Judge firmness of curd after cooling in water to 15-20C.
- After cooking, drain the whey until the whey first disappears below the surface of the curd mass, and then add the first wash water. If three wash waters are used, the first is at 20-25C the second at 10C and the third at 1.5-5C. If two wash waters are used, the first is at 15C and the second at 1.5-5C. The curd should remain in contact with each wash for 15 to 20 min and should be stirred frequently but carefully.
- Trench the curd carefully while draining the final wash water. Continue draining until the free water has completely drained (30-60 min).
- Add salt (1% of the weight of curd) either directly to the curd or in the cream.
- Add homogenized cream (18%) to give 4% fat in the creamed curd. If cream of lower fat content is used it is necessary to increase its viscosity using stabilizers to prevent excess free cream in the curd.
Expected yield: 6 x casein content or about 14 - 16%.
The A-C Test
- Add starter to the skim milk in the vat. Mix well.
- Place a sample of the well-mixed starter and skim milk in the A-C test beaker. Cover and take precautions against cooling.
- Add rennet to the skim milk in the vat immediately after taking the A-C test sample. Mix well.
- Immediately suspend the A-C test beaker in the vat so that the surface of the skim milk in the beaker is a little below that in the vat. Cover the vat.
- Periodically check the vat for coagulation. After it is coagulated begin to check the A-C beaker for coagulation with a spatula or thin knife with as little disturbance of the skim milk as possible.
- As soon as coagulation in the A-C beaker is first detected, cut the coagulating skim milk 2 or 3 times with the spatula and repeat the operation at 5 min intervals.
- Observe the surface of the A-C test samples for the appearance of fine lines of whey in the cuts made previously with a spatula. The A-C end-point is that time when the fine lines of whey first appear and usually occurs 1 - 20 min after coagulation is first detected.
Emmons, D.B. and Tuckey, S.L. 1967. Pfizer cheese Monographs -7. Cottage cheese and other cultured products. Pfizer & Co. New York, N.Y.