The time during which the Curd stands.
This is also of importance. It should be broken up as soon as the milk is fully coagulated. The longer it stands after this, the harder and tougher it will become.
The quality of the Rennet.
This is of much importance, not only in regard to the certainty of the coagulation, but also to the flavor of the cheese. In some parts of Cheshire, it is usual to take a piece of the dried membrane and steep it overnight with a little salt for the ensuing morning's milk. It is thus sure to be fresh and sweet, if the dried maw be in good preservation. But where it is customary to steep several skins at a time, and to bottle the rennet for after-use, it is very necessary to saturate the solution completely with salt, and to season it with spices, in order that it may be preserved in a sweet and wholesome state.
The quantity of Rennet added.
This ought to be regulated as carefully as the temperature of the milk. Too much renders the curd tough; too little causes the loss of much time, and may permit a larger portion of the butter to separate itself from the curd. It is to be expected also, that when rennet is used in great excess, a portion of it will remain in the curd, and will naturally affect the kind and rapidity of the changes it afterwards undergoes. Thus, it is said to cause the cheese to heave or swell out from fermentation. It is probable, also, that it will affect the flavor which the cheese acquires by keeping. Thus it may be, that the agreeable or unpleasant taste of the cheeses of certain districts or dairies may be less due to the quality of the pastures or of the milk itself, than to the quantity of rennet with which it has there been customary to coagulate the milk.
The way in which the Rennet is made.
This, no less than its state of preservation and the quantity employed, may also influence the flavor or other qualities of the cheese. For instance, in the manufacture of a celebrated French cheese, that of Epoisse, the rennet is prepared as follows:—Four fresh calf-skins, with the curd they contain, are well washed in water, chopped into small pieces, and digested in a mixture of 5 quarts of brandy with 15 of water, adding at the same time 2½ lbs. of salt, half an ounce of black pepper, and a quarter of an ounce each of cloves and fennel seeds. At the end of six weeks, the liquor is filtered and preserved in well-corked bottles, while the membrane is put into salt-water to form a new portion of rennet. For making rich cheeses, the rennet should always be filtered clear.
On Mont d'Or, the rennet is made with white wine and vinegar. An ounce of common salt is dissolved in a mixture of half a pint of vinegar with 2½ pints of white wine, and in this solution a prepared goat's stomach or a piece of dried pig's bladder is steeped for a length of time. A single spoonful of this rennet is said to be sufficient for 45 or 50 quarts of milk. No doubt the acid of the vinegar and of the wine aid the coagulating power derived from the membrane.