Cheese making

Cheese making and cheese yield basics

This is a complex subject if one goes into the detail required for volume manufacturing of a consistently good cheese with good flavour, body and texture and with optimum cheese yield coupled with a rapidly developed flavour profile

Cheese making (cheesemaking) is a process of preservation / conversion of milk solids by the use of specific "good" bacteria which put simply "eat" the milk solids and in the process produce acid which assists in the flavour creation and in the gelling of the cheese milk to allow the seperation of the curds (cheese solids) and whey. Coagulation in cheesemaking is assisted by the use of rennet (an enzyme now mostly of vegetable origin due mainly to fears of BSE in animal origin rennet and also for vegeterian cheese requirements)

The finished cheese continues to ripen with live bacterea under controlled temperature and humidity conditions - a good strong 2 year old cheddar type cheese can be extremely acidic and one of the benefits of making a matured cheese is that if there is a bacterial issue then it will likely not be there in 6 months time mainly due to the acid development during the ripening process

Cheese milk should ideally be seperated (fat removed) bactofugated or Microfiltered to remove "unwanted" bacteria then pasteurized and cooled to a specific temperature which is dependant upon the bacteria to be used which in turn is dependant upon the type of cheese to be made and the flavour profile desired.

The main requirement for a good cheese is to start with a good quality of milk with a low microbial count (no pathogens) and good protein and fat content.

To optimize the production then the cheese milk constituents should be standardized to suit the product to be manufactured i.e. full fat mozzarella cheese or low fat mozzarella cheese etc

After pasteurizing, cooling and standardizing of fat (dependant upon the cheese type and desired fat content)(and fat to casein ratio should also be standardized for optimum yield) into a vat at a specific temperature the cheese milk is innoculated and then left for a given time for the bacteria to flourish and convert the milk solids to acid and also create flavour compounds

This process is critical to the success of the cheese and hygiene is of utmost importance

Cheese bacteria are susceptible to attack by "phage" which can be likened to a very fast acting "virus" in humans and once the cheesemilk has suffered a phage attack then there is no recovering and it is likely that the cheese will not coagulate fully and acid / flavour will not develop and invariably the milk is wasted or at best the resultant weak cheese is sold for addition to a processed cheese product at a much reduced value.

At a given stage in the process where bacteria at at their optimum development then the coagulation enzyme "rennet" is added and gently stirred into the cheese milk in the vat

The vat stirrers / cutters are critical to the consistency of the cheese as is the temperature of heating of the cheese milk (maintaining optimum temeprature in the vat)

The stirrers are stopped and the cheese milk is allowed to set to a civen consistency in the vat

Once this is achieved then the coagulum is cut into small cubes using (in automated vats) the cheese stirrers / cutters, cutting time / profile is critical to cheese yield

The curds and whey are now seperate and most of the whey is drained off the vat and the remainder is used as a transfer medium to pump the surds and whey to a draining belt or table wher the balance is drained away and then salt added

The curds are then blown to a tower for automatic moulding or hand moulded or simpley conveyed to moulds or for further processing as with mozzarella cheese

Cheese whey traditionally seen as a by product of cheesemaking is now seen as a valuable commodity.

Whey proteins are now recognised as being a particularly valuable food protein supplement used widely in health foods and in Infant Formula Milk Powders with demand growing at an increasing pace annually

For assistance with cheesemaking or HACCP analysis for milk production and cheesemaking (Hazard analysis critical control point) then please use email

 

CHEESE YIELD

The Casein to Fat ratio

It is the Casein/Fat ratio which pre-determines the strength of the coagulum at cutting which in turn governs the following parameters:

• The degree of curd shattering which, when excessive, reduces yield in the form of fines in whey

• The fat retention in the curd, also affecting yield .

• The rate and consistency of syneresis affecting final cheese moisture , ripening potential, body and texture grades .

From data collected from parts of Europe the Casein % of Protein varies from 75.5 - 80.0% giving a possible range of 4.5%

Using the Van Slyke yield formula

Cheese Yield = [(%Milk Fat x 0.93) + (%Milk Casein - 0.1)] x 1.09 Total Solids in Cheese / 100

Casein 2.49% - 2.64% (2.56% mean)

Fat 4.1%

Protein 3.3%

vat milk at 3.76% fat making cheddar cheese at 35% moisture, FDM 53.9 and £2.00/kg

Casein Yield kg cheese / 100kg milk 2.49 9.861 2.56 9.990 2.64 10.119

Cheese Yield and Profit

Cheese yield can vary from 9.861 - 10.119 difference of 0.258kg cheese / 100kg milk in a plant processing 20 million kg milk/year and cheese worth $4/kg the value is 51,600kg (2.6% of production) or approx $200,000 per year