430 TJie Practice of Cheshire Cheese Malnng. 
pure and good it may be used in a liquid state or as a powder, 
or direct from the skin. It is of great importance to have 
it of uniform strength, to know what that strength is, and 
to use the right quantity. The most practical and reliable 
way of ascertaining the strength is to take a drachm of the 
liquid, or a fixed portion of the powder, and mix it with five 
gallons of milk at the temperature it is usual to set the whole 
of the milk together, and to notice how long it is before it 
begins to thicken. If this occurs in from 20 to 25 minutes 
the right proportions will have been found. If it takes a 
longer time more rennet is required. If a shorter time a less 
quantity should be used. The exact quantity can only be fixed 
upon by repeated careful tests in individual dairies. Too much 
rennet causes the curd to become dry and brittle, too little leaves 
it soft and spongy. The use of the cured and dried skins in 
pieces cut off daily is not recommended, nor is the use of highly 
concentrated or very strong rennet in powder ; the former is 
irregular in strength, and the latter requires great nicety in 
measuring. The liquid state allows of most accuracy in use. The 
action of rennet on milk is to coagulate the caseine, in which 
act it encloses the butter-fats, and then causes a separation of 
these solids from the liquid whey. Rennet also acts in harmony 
with acidity in reducing or softening the fibre of the curd, in 
assimilating moisture, and in forming the consistency of the ripe 
product. 
Salt gives flavour to the curd, and checks the further 
development of acidity after it is mixed with it, helps drainage, 
regulates the ripening influence of rennet, and in some degree 
arrests decay. About 6^ oz. to 20 lbs. of curd are used in the 
early spring, 8 oz. to 20 lbs. in the summer, increasing to as much 
as 9 oz. as the milk becomes richer in the autumn. An over- 
acid curd requires less salt than the quantities named, while an 
under-acid moist curd does not receive much benefit from a larger 
addition of it. 
Pressure binds together and consolidates the curd and helps 
to expel the moisture ; it should be applied gradually, for, if too 
great a weight is applied, the first day some fatty matter goes 
off in the whey. A curd having a tendency to over-acidity 
should only be lightly pressed, to retain as much moisture as 
possible, while no amount of pressure will get the whey out of 
a moist under-acid curd, and when it leaves the press it " heaves," 
owing, no doubt, to the uncontrolled action of ferments which 
form gases in the body of the cheese. 
It is not possible to lay down any exact rule or rigid order 
of procedure in making which will answer under all the varied 
