The Art of Cheesemaking:

1
The Art of Cheesemaking

• No one knows who first made cheese, but the most
  popular story is that an Arab put milk into a bag
  made from a sheeps stomach to take with him on a
  trip.
• By the time he was ready for a drink, the rennet
  from the sheeps stomach, along with the warmth
  and gentle agitation had turned his milk into a
  type of cheese.

2
The Art of Cheesemaking

• Milk is separated and standardized to obtain the
  desired fat content for the cheese. Some
  factories also add or remove protein to obtain a
  desired protein level. It is then pasteurized and
  transferred to tanks where starter culture and a
  rennet enzyme is added.
• Curdling (Coagulation) - is due to the enzymatic
  activity of Rennet (aka Rennin), which was
  traditionally obtained from the stomach of
  unweaned calves. It reacts with the casein
  protein in the milk to convert it into curd, the
  main element of cheese. This curd also contains a
  large proportion of whey, a watery substance full
  of sugar.
• Cutting - The whey is separated from the curd by
  cutting it. The finer the cuts, the larger the
  total surface of the curd become and therefore
  the more whey that can be released.
• For the softer types of cheese the curd is hardly
  cut at all. For the hard varieties it is first
  cut into large pieces and then gradually into
  smaller ones, expelling as much whey as possible.
• Continue

3
The Art of Cheesemaking

• After Cutting
• Cooking - After the cutting step the curd is
  cooked, using a jacket of heated water around the
  vat. This is done to expel moisture.
• Draining - Once a fairly solid mass of curd is
  obtained, it is pressed to expel further whey.
  This either done in block forming towers (dry
  salt production) or collected in moulds and
  pressed further (brine salt production). Salt is
  added before this process in dry salt production
  while brine salt production sees the cheese being
  immersed in a brine solution after being in
  moulds.
• Ripening - The cheese is left to ripen in a
  temperature controlled environment. This ripening
  period allows the various enzymes, acids and
  bacteria to spread throughout the cheese,
  developing each cheese's distinctive taste.

4
The Art of Biotech Cheesemaking

• The use of Chymosin (genetically-engineered
  rennin or rennet) for cheese-making was the first
  commercial application of food biotech (1988).
• In the 1960s the Food and Agriculture
  Organization of the United Nations predicted a
  severe shortage of calf rennet. It was
  anticipated that an increased demand for meat
  would lead to more calves being reared to
  maturity, and hence less rennet would be
  available. Over the last 30 years several
  substitutes for calf rennet have been developed,
  allowing the supply of enzymes to keep pace with
  cheese production.
• The first Chymosins in the early 1980s were
  derived from genetically-modified microbes
  (Escherichia coli, Kluyveromyces lactis and
  Aspergillus niger). Numerous groups have since
  followed their lead, using other microbes, so
  that chymosin has now been obtained from food
  yeasts. Today about 90 of the hard cheese is
  made using chymosin from genetically-modified
  microbes
• Chymosin is identical to the enzyme obtained from
  animals. This can be used to produce better
  quality cheese than the fungal or other animal
  (non-calf) rennets. These bioengineered enzymes
  behave in exactly the same way as calf rennin,
  but their activity is more predictable and they
  have fewer impurities. Such enzymes have gained
  the support of vegetarian organizations and of
  some religious authorities. Chymosin obtained
  from recombinant organisms has been subjected to
  rigorous tests to ensure its purity.

5
How Chymosin is marketed to the public and those
seeking natural alternatives
Highly recommended by some of the best known
cheesemakers this is a high quality rennet,
originating from animal sources, but containing
no animal products itself. A vegetable product
with animal origins www.cheesmaking.com
Food for thought Chymosin (Chymostar) is a
genetically engineered enzyme, produced by yeast
cells.
6
Try Your Hand at Making Cheese with Chymosin

• Add 0.5 ml of skim milk (_at_ RT) to a microfuge
  tube.
• Add approximately 20 microliters of Chymosin
  (curdling enzyme) to the tube containing the
  milk.
• Gently mix and warm the tube between your hands
  for about 5 minutes (this mimics the conditions
  in the stomach of a calf . . . the churning
  action of the stomach).
• Check the tube every 1-2 minutes to check for
  curdling.
• The final product should resemble Cottage Cheese
  (the next step would be to separate the curd from
  the whey)