Removing the whey before the curd is properly firmed, hence leaving it with too much moisture.
Development of too much acid in the whey before the whey is removed.
Improper relationship between the moisture and acidity at the time of removing the whey.
Conditions causing deficient acid:
Adding the rennet before sufficient acid has developed.
Not using sufficient starter.
Not developing sufficient acid in the whey.
86. Acidity and rennet action.—The rennet extract acts only in an acid medium. The greater the acid development, within certain limits, the faster the action of the rennet. If enough acid has developed to cause a coagulation of the casein, the rennet will not coagulate the milk. This is one reason why Cheddar cheese cannot be made from sour milk.
87. Acidity and expulsion of the whey.—The contraction of the curd and expulsion of the whey are so closely related that they may be treated under the same heading. The more acid, the faster the whey separates from the curd, other conditions being uniform. The relation of acidity and firmness of the curd to temperature of the curd is another important factor in the successful manufacture of cheese. The higher the acidity, the faster the temperature of the curd can be raised without any harmful effects. If the temperature is raised too fast in relation to the acidity, the film surrounding each piece of curd will become toughened so that the moisture will not be able to escape. When this condition exists, the curd will feel firm but when the pieces are broken open the inside is found to be very soft. This results in a large loss later or may cause a sour cheese. It usually causes an uneven texture and color in the cheese.
88. Acidity in relation to cheese flavor.—Just what part the acid plays in the development of cheese flavor is not known. If a certain amount of acid is not present, the characteristic cheese flavor does not develop. If too much acid is developed, it gives the cheese a sour flavor which is unpleasant. If sufficient acid is not developed, the other undesirable factors seem to be more active, causing very disagreeable flavor and may cause the cheese to putrefy. A cheese with a low acid usually develops a very mild flavor, and if carried to extremes, as in the case of some washed curd cheese, the true cheese flavor never develops.