User:Cheesemaker1/sandbox

(''For a less technical introduction to the topic see Cheese)

At its most basic, cheese making is the partial dehydration of milk, usually accompanied by fermentation. Cheese production and cheese making recipes are distinguished by the steps carried out and the extent to which each process is applied and this in turn distinguishes the resultant cheese. Current methods range from the traditional artisan to modern block cheese production and milk protein extraction. Training in cheesemaking ranges from oral tradition to 3 year courses at dairy schools in France.

Cheese making history
The separating of solids and whey in milk has historically involved coagulating the milk either by acidifying and heating or use of animal stomachs or plant extracts.

Production of natural animal rennet before about 160 years ago, was by the cheesemaker on the farm. When a lamb, calf or kid was slaughtered the stomach was cleaned and salted and hung up to dry. Then it was stored in a cool place, and when required for cheesemaking, they broke off a small piece of the dried stomach and soaked it in cool water for several hours. A bit of the resultant solution was then added to ripened milk to produce a curd. An alternative method involved the colostrum filled stomach of a calf or a kid slaughtered at not more than two days old. The colostrum was carefully removed, and set aside while the stomach was thoroughly cleaned inside and out it was then returned to the stomach which was sealed and hung in a cool place to age. The colostrum would set into a lard-like substance, which would then be cold stored in a tightly covered container. A "thumbnail's worth" of this paste would be used to set two gallons of milk. Finely grated cheese may be added to the colostrum as it was returned to the stomach to age to produce rennet that was culture and coagulant all in one. (ref)

These methods remain in use today for most modern cheese production, although coagulation is largely effected by microbial 'rennets'.

Lactic and soft cheeses
Acid set and cottage cheese yogurt vs cheese ferment Kafer Tarhana

straining/draining presalting method ladling into moulds and salting method Usually goat cheeses

Hard cheesemaking
Below is a general route to most hard cheeses including alpine cheeses such as comte beuford parmesan emmetial and traditional English territorials. Modern cheddar style cheeses are made similarly but many of the steps are left out or shorted to speed up the process.

Preferment

In some cheesemaking processes a prefermentation of the milk is used to increase the flavour. This is done by addition of small amounts of starter bacteria and leaving the milk at around 16C overnight. This is useful for small producers as a way of keeping the evenings milk which is then added to the next mornings milking leading to the right temperature for reuniting.

The milk may also be skimmed at this stage

Heating

Milk is usually cooled for holding or transport and must be warmed up to make cheese. Heated in vat by hot water or steam or burning of gas or wood or heat exchange (e.g. pasteurisation)

Addition of starter

A source of lactic acid bacteria is usually added before the rennet, when the milk is warm (28C - 40C). Anatto (red food colouring) may also be added at this stage.

Renneting

In the traditional method still used by some cheese-makers, particularly in Switzerland, France, Romania, Italy, Sweden and Alp-Sennereien in Austria, the dried and cleaned stomachs of young calves are sliced into small pieces and then put into saltwater or whey, together with some vinegar or wine to lower the pH of the solution. After some time (overnight or several days), the solution is filtered. The crude rennet that remains in the filtered solution can then be used to coagulate milk. About 1 gram of this solution can normally coagulate 2 to 4 litres of milk.

breaking or cutting of curd

scolding and pitch

blocking of curd

milling

clothing/moulding and pressing

affinage and washing

Effects of acid and moisture
Calcium pH vs titratable acidity

Gouda Comte Cheddar Cheshire Caerphilly Lancashire Wensleydale Stilton

Blue cheeses
General features Rocfor Gorgonzola Stilton

Methods of separating milk solids from water or whey
Milk coagulation

The main types of protein in milk are α, β and κ-caseins. The α, β-caseins are insoluble in milk due to the high calcium levels and are bound up along with calcium phosphate into casein clumps called micelles. The κ-casein is insoluble only at one end which attaches to the surface of the micelles. The other end is a water soluble, negatively charged glycopeptide (protein combined with carbohydrate). The micelle’s surface is covered by κ-caseins causing micelles to repel each other and remain suspended in the milk.

Acid Coagulation
pH and Casein solubility

Renneting
Enzymatic milk coagulates are proteases enzymes that can hydrolyse the κ-caseins cutting off the hydrophilic ends. When more than 85% of the κ-caseins is hydrolysed the micelle suspension is destabilised and the remaining ends of the κ-caseins (para-casein) linkup (coagulate) to form a network called phosphocaseinate or curd.

Protease enzymes are present in most living tissue many of which are capable of hydrolysing k-casein and thereby coagulating milk. However most of these enzymes have a much broader activity than chymosin and will break down curd protein non-selectively generating bitter peptides during the cheese ripening. A few natural enzymes have been found that are sufficiently selective to allow their use in the production of cheese with acceptable levels of bitterness mostly those of fungi but also those of animals and plants.

Natural animal rennet (Animal chymosin)

Rennet in the strictest sense refers to a natural complex of enzymes produced by the mammalian stomach to digest the mother's milk. The most important enzyme in rennet in the production of cheese is a protease called chymosin or rennin but there are also other important enzymes such as pepsin (also a protease) and lipases. Chymosin is general considered to be the best milk coagulant for cheesemaking. Unlike other enzymes chymosin hydrolyses only a specific link between phenylalanine and methionine along the length of the κ-caseins leaving other proteins intact. At lower pH chymosin becomes more active (but peaks for κ-caseins around pH 6.0) and less selective and breaks down other protein in cheese ripening. Calf rennets activity peaks around 43°C (see attached sheets) consistent with its origin in calf’s stomachs.2 Chymosin is produced by gastric chief-cells in the infants of some mammals to curdle the milk they ingest, allowing a longer residence in the bowels and better absorption (A chymosin type gene is found in humans (on chromosome 1) but it is not expressed). In natural calf rennet extract three main types of chymosin are identified; ‘A’, ’B’ and ’C’ as well as a small amounts of subtypes

K-Casein proteins found in cow’s milk micelles vary in their structure the hydrophilic terminus having ten variants and there are also genetic variants between cows. It has been argued that it is because of this variation that there are different types of chymosin and that natural rennet extract can give better clotting than a pure extract of a single chymosin type (see fermented chymosin below).

Pepsin is less selective than chymosin and can cause undesired bittering in the ripening of cheese. The proportion of pepsin in rennet is therefore important and increases with the age of the animal. Reliable modern rennet extracts have standardised pepsins levels, below 20% of the chymosin levels in quality extracts.

In 1 kg of rennet extract there are about 0.7 grams of active enzymes – the rest is water and salt and sometimes sodium benzoate, E211, 0.5% - 1% for preservation. Typically, 1 kg of cheese contains about 0.0003 grams of rennet enzymes. Although calf rennet can be used for all types of milk, each ruminant does produces its own kind of rennet to digest the milk of its mother and there are milk-specific rennets available, such as kid goat rennet especially for goat's milk and lamb rennet for sheep's milk.

Animal pepsins

Three animal pepsins have been found to be more or less acceptable for cheese production: bovine, porcine and chicken. •	Bovine pepsin is probably the most satisfactory of these but loses activity as the cheese pH drops limiting the ripening process. •	Porcine pepsin can be used but has been withdrawn from most markets •	Chicken pepsin is the least suitable of the commercial rennet substitutes and was used widely only in Israel, now replaced by microbial chymosin.

Microbial

Microbial pepsins

Commercially viable milk coagulating enzymes can be extracted from moulds such as Mucor (old name Rhizomucor) miehei, M. pusillus and Cryphonectria parasitica and even bacteria such as Bacillus polymyxa. The moulds are produced in a fermenter and then concentrated and purified to reduce contamination with by products of the mould growth. A variety of enzymic extracts can be obtained from a given mould, for example, two different extracts of M. miehei are available from commercial dairy suppilers one of which is the more thermolabile being deactivated by pasteurisation like chymosin. Microbial pepsins are cheaper to produce than calf chymosin but have a higher proteolytic activity which can give bitter flavours if used excessivly and a loss of protein into the whey giving a 0.5 -1% reduction in the cheese yield.

Microbial ferment chymosin (genetically engineered rennet)

With the development of genetic engineering, it became possible to use cow genes to modify some bacteria, fungi or yeasts to make them produce chymosin. The gene for chymosin has been inserted into microbes chosen for ease of fermented and extraction. Chymosin produced by genetically modified organisms was the first artificially produced enzyme to be registered and allowed by the U.S. Food and Drug Administration. Most bovine chymosin use in cheese production now comes from recombinant E. coli, Aspergillus niger var awamori, and K. lactis. Being cheaper to produce and not limited in availability, by 1999, about 60% of U.S. hard cheese was made with genetically engineered chymosin. By 2008, approximately 80 - 90% of commercially made cheeses in the United States were made utilizing GMO-based rennet and today about 50% worldwide. Today the most widely used genetically engineered rennet is produced by the fungus Aspergillus niger Cheese produced with genetically engineered rennet is very similar to cheese produced with natural calf rennet although GMO-produced rennet contains only one of the known main chymosin types, either type A or type B. Other chymosin types found in natural rennet do not exist in GMO-produced rennet. Often a mixture of genetically engineered chymosin and natural pepsin is used to imitate the complexity of natural rennet and to get the same results in coagulation and in development of flavour and taste. The so-called "GM rennets" are suitable for vegetarians if there was no animal based alimentation used during the production in the fermenter. However, those with soy-based allergies should beware as GM soy rennet or phytic acid, derived from unfermented soybeans may be used

Plant enzymes

Many plants have coagulating properties including nettles (Urtica gracilis), mallow (Glechoma hederacea), Ground Ivy thistles and many fruit (see Table 1).5 Fruit	              Enzyme Fig, Ficin Pineapple Bromelain Papaya, Papain Kiwi, Actinidin Melon Cucumisin Table 1. Although in the Iliad Homer suggests that the Greeks used an extract of fig juice to coagulate milk, fruit enzymes generally cause bitterness even to the extent that the use of the raw pineapple or papaya in milk deserts should be avoided. Cynara cardunculus Pedroches, Torta del Casar.

Heating
Effect on renneted curd: scold/cooked cheese, pastafalta

Effect on acidified milk: ricotta, Pannier

Micro filtration
Some commodity cheese

Milk fermentation
Lactose, Homo and hetero fermentation

Non-starter microbes
Unpasteurised milk

Starter microbes
Types: Lactic, Lactoccocos, straptoccos,

Whey
Back slopping Itailian

Commercial
Strains available Bespoke starters: Comte cheese Pint starters DVIs

Cheese presses
belted mould and follower mould and ring

Milling
Salt is usually added to cheddar style cheeses at the milling stage where

Rubbing
Alpine style cheeses are rubbed with salt. Comte beuford tellageo

Brining
Caerphilly, gouda, feta, Parmesan

Cheese maturation/aging
From a few days to decade but usually no more than 2 to 3 years.

Moulded 'bloomy rind' and natural
wiled cheese flora yeasts and blue moulds, penicillin candidium and P. G, geotricum,

Cloth - larded - buttered - flour and water
Cheddar, Lancashire, cheshire

Plasticoat
Gouda

Dry and oiled
Parmesan, Pec

Barrelled -In brine -In grain -In grape must
Traditional feta is aged in brine soaked barrels. Some spanish cheeses are aged barrels with fermented red grape must turning the outside of the cheese purple. Small Italian cheesemakers age cheese in barrels of grain, which leave a district patten on the outside of the cheese.

Potted cheese
Fromage fort Stilton and port

No rind -Vac-bagged
Block cheese

Cheese spoilage
Blowing and cracking Mucor pseudomonas

Preserving factors
Water activity, pH, microbe competition

Cheesemaking Associations
Specialist Cheesemakers Association (SCA)

Association Fromages de Terroirs

Raw Milk Cheesemakers Association

Wisconsin Cheese Makers Association

Washington State Cheesemakers Association (WaSCA)