Department of Food Science

University of Guelph, ON N1G 2W1

Email: Dr. A.R. Hill

Cheese is made from the milk of goats, sheep, buffalo, reindeer, camel, llama, and yak but is usually made from cow’s milk. Cow’s milk is about 88% water and the remainder is fat, protein, sugar, minerals and vitamins. In the process of cheese-making, most of the protein, fat and some minerals and vitamins are concentrated and separated as a solid. The remaining liquid, called ‘whey’, contains most of the sugar and water and some protein, minerals and vitamins. Whey is utilized in foods and feeds or disposed of as waste.

There are two principal agents which bring about the concentration and separation of protein and fat to make cheese, namely, bacterial culture and coagulating enzyme.

Bacterial culture

Bacteria are often responsible for food spoilage but there are also many useful types. During the manufacture of cheese and other cultured dairy products lactic acid bacteria change the milk sugar to lactic acid. The acid acts as a preservative by inhibiting undesirable types of bacteria, helps remove water from the curd (formation of curd is described in the next section) and is important to the development of cheese texture. The lactic acid bacteria and other microorganisms which happen to be present in the cheese contribute enzymes which break down fats, proteins and sugar during aging to produce flavours characteristic of particular cheese varieties. Lactic acid bacteria are naturally present in milk, and cheese can be made by holding fresh milk in a warm environment. However, this process is slow and cheese quality tends to be inconsistent. It is recommended that the milk be pasteurized by heating at 60-62C (140-144F) for 30 min . This heat treatment will destroy most lactic acid bacteria in the milk and will also destroy pathogenic bacteria which may cause food illness. Note that over pasteurization will prevent proper coagulation. Most store bought milk is unsuitable for cheese making because it has received too much heat treatment.

After pasteurization the milk is cooled to 32-37C (89.6-98.6F) and lactic acid bacteria are added to the milk. The suspension of bacteria is called a ‘culture’ and the process of adding the culture to the milk is called ‘inoculation’. The culture may be a frozen or freeze-dried concentrate of bacterial cells or it could be cultured milk (milk in which lactic acid bacteria have been allowed to grow). Different bacterial cultures are recommended for specific types of cheese but most types can be made using fresh, plain yoghurt or buttermilk as a culture. If yoghurt is used, the milk should be inoculated at 37C. Buttermilk contains gas forming bacteria and may cause the development of small eyes in some cheese. In addition to bacteria, some types of cheese such as ‘blue’ and ‘camembert’ are inoculated with mould to develop characteristic appearance and flavour.

Coagulating enzymes

Proteins can be thought of as long microscopic chains. Various food products such as jello, jams and cheese depend on the ability of protein chains to intertwine and form a mesh-like network. The formation of this network is called ‘coagulation’. When proteins coagulate in water, they trap water in the network and change the liquid to a semisolid gel. In cheese-making gelation is caused by an enzyme, ‘rennet’. When rennet is added to warm milk, the liquid milk is transformed into a soft gel. When the gel is firm enough, it is cut into small pieces, 0.5-1.0 cm square (1/4-3/8 inch) called ‘curds’.

 Exceptions

Certain types of cheese such as some types of Queso Blanco (Latin American countries) and Paneer (India) are made without bacterial cultures and without rennet. In these types, curd is formed by adding vinegar (or other acid juices) to hot milk. A procedure for heat-acid precipitated Queso Blanco is included in this booklet because it is one of the most simple varieties to make and has the advantage that all the milk proteins including proteins normally lost in the whey are included in the cheese. Some fresh cheese (i.e. cheese which are eaten immediately after manufacture) such as Cottage cheese and quark are made with little or no rennet. In these cheese, coagulation is caused by high acid development by the bacterial culture. A procedure for fresh cheese or European style Cottage cheese is included.

Cheese-making supplies and training

For the home cheese maker, a start up set of supplies should include: a pasteuriser, cheese mould, cheese press, dairy thermometer or any food grade thermometer for the range of 0 to 100C, and cheese cloth. Bacterial cultures and rennet can sometimes be purchased in natural food stores.

Small scale cheese making equipment and other supplies, including literature, can be obtained from New England Cheese Making Supply Company, 85 Main St., Ashfield, MA 01330 (413-628-3808; Fax: 413-628-4061).

Cheese making supplies and one day courses in cheese making are available from Glengarry Cheesemaking and Dairy Supplies, RR#2,Alexandria, Ontario, K0C 1A0 Phone: (613) 525-3133, Fax: (613) 525-3394, glengarrycheesemaking.on.ca

Cultures, rennet, cheesemaking equipment and other supplies are available from Danlac, 466 Summerwood Place, Airdrie, Alberta, T4B 1W5, Phone 403-948-4644, Fax 403-948-4643, www.danlac.com, e-mail Egon Skovmose

Freeze dried cultures and rennet in tablet form are available in large orders from Chr. Hansens Laboratories Ltd., 1146 Aerowood Drive, Mississauga, L4N 1Y5, 905-625-8157, and from Rhodia Canada Inc., 2000 Argentia Road, Plaza 3, Suite 400, Mississauga, Ontario, L5N 1V9, Phone 905-821-4450, Fax 905-821-9339. Call and ask about retail distributors closest to you.

Some References

Alfa-Laval. Dairy Handbook. Alfa-Laval, Food Engineering AB. P.O. Box 65, S-221 00 Lund, Sweden. [Well illustrated text. Excellent introduction to dairy technology].

American Public Health Association, Standard Methods for the examination of dairy products. 1015 Eighteenth St. NW, Washington, D.C.

Berger, W., Klostermeyer, H., Merkenich, K. and Uhlmann, G. 1989. Processed Cheese Manufacture, A JOHA guide. BK Ladenburg, Ladenburg.

Carroll, R. and Carroll, R. 1982. Cheese making made easy. Storey Communications Inc., Ponnal, Vermont. [Well illustrated manual for small and home cheese making operations]

Kosikowski, F.V. and Mistry, V.V. 1997. Cheese and Fermented Milk Foods, 3rd Edition, F.V. Kosikowski and Associates, Brooktondale, NY.

Law, B. 1999. Technology of cheese making Sheffield Academic Press, Sheffield, UK.

Scott, R., Robinson, R.K. and Wilbey, R.A. 1998. Cheese making Practice. 3rd Edition. Applied Science. Publ. Ltd., London.

Troller, J.A. 1993. Sanitation in Food Processing. 2nd Edition. Academic Press. New York.

Walstra, P., Geurts, T.J., Noomen, A., Jellema, A. and van Boekel, M.A.. 1999. Dairy Technology. Marcel Dekker Inc. New York, NY.

Websites

Food Science University of Guelph: http://www.uoguelph.ca/foodscience/content/dairy-education-series

Centre For Dairy Research, Madison, WI. www.cdr.wisc.edu/

Canadian Dairy Information Centre, www.dairyinfo.gc.ca

CheeseNet , cheesenet.wgx.com/

 

SWEET CURD BRICK CHEESE

Brick cheese is a semi-soft ripened cheese. Its texture and flavour is derived from the action of bacteria which grow on the surface of the cheese. It is usually formed in the shape of a loaf.

Procedure

1. Pasteurize whole milk by heating at 62C for 30 min. Do not over pasteurize.
2. Cool milk to 30C and add 25 ml of low temperature (sometimes called mesophyllic cheese starter and 2 ml of rennet per 10 kg of milk. (Note: a bacterial smear should develop spontaneously during ripening in the wet room (Step 12), however, you can increase the success rate and uniformity by adding a smear culture with the lactic culture. Suitable cultures are available from many culture suppliers)
3. When the milk gel breaks cleanly on a knife (about 25 minutes after adding rennet), cut the gel into 1/4″ cubes.
4. Stir gently for 10 minutes.
5. Begin cooking. Slowly raise the temperature to 36C. This should take 20 minutes.
6. Remove most of the whey but leave enough to cover the curd.
7. Add water at 36C to wash the curd. Add the equivalent of half the weight of the milk and agitate gently for 20 minutes.
8. Drain most of the whey but leave enough to cover the curd.
9. Pour the curd and remaining wash water into the hoops.
10. Turn the cheese after the first 30 minutes and then every hour for 4 hours (5 turns in all).
11. Rub salt over the entire surface of the cheese.
12. Store cheese in a wet room (95% humidity) at 12-15C to develop a smear (bacterial growth on surface) for about 2 weeks. Turn the cheese every second or third day and wash with 4% brine. In the absence of a wet room you can put the cheese in a covered but not sealed container. The interior must remain moist and have some air exchange.
13. Wash cheese to remove smear, dry and vacuum package or coat with paraffin. Store at 5C for further ripening. Flavour should be optimum after about 4 weeks of ripening.

 

EUROPEAN STYLE COTTAGE CHEESE

European style cottage cheese has small curds and is often heavily creamed. The milk is coagulated by a lactic culture without rennet or other coagulating enzyme.

Procedure

1. Skim as much cream as possible from fresh milk.
2. Pasteurize the skim milk at 62C for 30 minutes and the cream at 70C for 30 minutes.
3. Cool the skim milk to 32C.
4. Add a low temperature cheese starter at the rate of 5%, i.e. 0.5 kg starter for every 10 kg of milk. Let milk set for 4-6 hours until a soft gel is formed. When broken with a knife or a blunt object the curd should break cleanly and the broken portion should fill up with clear whey. Alternatively, 1% of culture may be used with a setting time of 12-18 hours.
5. Stir gently and heat slowly to 52C. Hold at this temperature until curd is firm, about 30 minutes.
6. Drain most of the whey, replace it with cold water and agitate gently for 15 minutes to leach the acid flavour from the curd. Washing may be omitted if you prefer an acid cheese.
7. Drain the remaining whey and wash water.
8. Add cream or cream dressing to the curd according to taste.

 Note: It may be convenient to drain the curd in a cloth bag, in which case, it could be washed by soaking the whole bag in cold water for 15 minutes.

 

NO-RENNET QUESO BLANCO (LATIN AMERICAN WHITE CHEESE)

Heat-acid or no-rennet Queso Blanco is a white, semi-hard cheese made without culture or rennet. It is eaten fresh and may be flavoured with peppers, caraway, onions, etc. It belongs to a family of “frying cheeses” which do not melt and may be deep fried or barbecued to a golden brown for a tasty snack. Deep fried Queso Blanco may be steeped in a sugar syrup for a dessert dish or added to soup as croutons. The procedure given here is similar to the manufacture of Indian Paneer and Channa which is made by adding acid to hot milk. Ricotta cheese is also made by heat-acid precipitation of proteins from blends of milk and whey. Latin American white cheese is also made by renneting whole milk with little or no bacterial culture. Rennet Queso Blanco is also useful as a frying cheese because its lack of acidity gives it low meltability.

Procedure

1. Heat milk to 80C for 20 minutes.
2. Add vinegar (5% acetic acid) at the rate of about 175 ml per 5 kg of milk. Vinegar should be diluted in two equal volumes of water and then added slowly to the hot milk until the whey is semi-clear and the curd particles begin to mat together and become slightly stretchy. You should be able to stretch a piece of curd about 1 cm before it breaks. It may not be necessary to add all of the vinegar.
3. Separate the curd by filtering through a cloth bag until free whey is removed.
4. Work in salt (about 1%) and spices to taste.
5. Press the curd (high pressure is not required).
6. Package curd in boilable bags (vacuum package if possible) and place in boiling water for 5 minutes to sterilize the surface and prevent mould growth.
7. Queso Blanco may keep for several weeks if properly packed but should be eaten as fresh as possible.

 

RICOTTA CHEESE RECIPE

1. Heat fresh whey to 85C. Heating must begin immediately after the whey is removed from the curd to prevent further acidification by the lactic acid bacteria. Some small curd particles will form.
2. Slowly add about 10 ml of vinegar per litre of whey with gentle agitation. You will see more curd particles forming and the whey will become less ‘milky’.
3. Pour into a cloth to separate the curds. After the curd is dripped dry it is ready to eat. Use it in lasagna or eat as a side dish along with the main course or use it like cottage cheese in salads.

Notes

Before heating the whey, you can add up to 10% whole milk (that is, 100 ml of milk in 1 litre of whey). Addition of milk will help form larger curds which are easier to separate and the cheese will have a better texture. You also have to add more vinegar depending on the amount of milk. Continue adding vinegar until the whey is quite clear. By adding the vinegar slowly over a time period of about 5 minutes you will obtain better quality curd and it will be easier to know when to stop.