Process of Cheese Making

Are you ready to begin your journey through home cheese making? Here are some cheese making basics to help you better understand the process.

Cheeses that do not require an aging process such as fresh cheeses, Chevre, Ricotta, Cream cheese, Cottage cheese, etc. undergo the following steps:

  1. Warming the milk
  2. Treating it with citric acid or a starter culture and rennet to help the acid development.
  3. Draining or removing the whey from the cheese
  4. The cheese is then ready to consume with no further aging or processing.

Cheeses that undergo a ripening and aging process (also known as a curing, maturing) are always treated with rennet.  Before the ripening process begins, they undergo the following steps:

  1. Milk is warmed
  2. A starter culture and rennet are added
  3. The milk coagulates into a single huge curd
  4. The curd is stirred and cut to drain off whey
  5. The curd is heated, sometimes pressed, to remove more whey
  6. The curd is molded and shaped into a cheese, salting always takes place before or after this process
  7. The cheese is aged under controlled conditions, most cheeses age at 55 degrees F and 80% humidity.

During the ripening period, the two most important factors are the length of the maturing time (10 days up to 10 years) and the temperature at which the cheese is matured. It is during this time that the microorganisms play their part. They may be present naturally in the milk or in the atmosphere of the curing room, or they can be artificially introduced.

Coagulation

The basic principle involved in making all natural cheese is to coagulate or curdle the milk so that it forms into protein and fats (known collectively as curds) and whey (that consists mainly of water). As anyone knows who has left milk out of the refrigerator for a period, milk will curdle quite naturally. The milk sours and forms into an acid curd.  Today's methods help the curdling process by the addition of a starter (a bacterial culture which produces lactic acid) and rennet, the coagulating enzyme, which speeds the separation of liquids (whey) and solids (curds).

There are two basic categories of starter cultures. Mesophilic starter cultures have microbes that cannot survive at high temperatures and thrive at room temperatures. Examples of cheeses made with these bacteria are Feta, Chevre, Farmhouse Cheddar and Gouda. Thermophilic starter cultures are heat-loving bacteria. They are used when the curd is cooked to as high as 132F.  Examples of cheese made with these bacteria are Parmesan, English style Cheddars, Provolone.

The process of coagulation is vitally important in the success of your cheese making.

In general, there are two main types of cheese.

  1. Those, which are made through coagulation of milk by acidification. The acidification can be by direct addition of an organic acid such as Citric Acid, lemon juice or vinegar or by "natural acidification" through acid produced by milk lactic acid bacteria. We never recommend the use of lemon juice or vinegar as it causes inconsistent results. Most of such type of cheese is consumed "fresh" or "soft", unpressed cheese.
  2. Cheese in which the milk is coagulated by means of enzymes (rennet). This is the most common type of coagulation. Milk is coagulated by means of enzymes extracted from the stomach of young calves or other sources, microbial or vegetarian. Most of this type of cheese if often pressed into various shapes, salted and ripened into "semi-hard" or "hard types". As with other types of foodstuffs, a variety of "preparation" recipes have resulted into thousands of types of ripened cheeses worldwide.

Starter culture

A starter culture in cheese making is a medium of harmless, active microorganisms, which by growing in cheese milk and curd, assists the development of mature cheese with desirable characteristics of flavor, aroma, pH, texture and body.

The choice of starter will depend on:

Type of cheese 

Cooking temperature to be used (influenced by type of cheese)

Certain types of cheese must use specific cultures if the desired result is to be obtained. Invisible to the naked eye, these cultures work alongside the numerous enzymes on the lactose, protein and fat through all the stages of cheese making. Each thrives at a specific range of temperatures and degree of acidity and contributes to the final flavor and texture of the cheese. As the level of acidity changes in the milk (and later in the young curd), some die off or become dormant, while others, preferring the new climate, will spring into action. Their unique characteristics combine to create a kaleidoscope of flavors that no amount of copying can emulate.

Rennet

Although the starter culture speeds up the process of souring the milk and would eventually cause it to curdle, it produces quite a sharp, acidic cheese, so it is only suitable when making a cheese that will be eaten young. The use of rennet significantly improves cheese making techniques, and it was its discovery centuries ago that allowed shepherds to make harder cheeses that lasted through the winter months when their animals and the land were barren. All milk-fed animals are born with an enzyme in their stomachs that attacks the milk and converts it into solids (which they can digest) and liquid (which is mainly waste). Legend states that the herdsman, discovered the effects of the enzyme, rennet when they stored their milk in sacks made from the stomach of a young kid or lamb and found the warm milk had soured slightly and separated into curds and whey. The use of this animal product made it so that many vegetarians were reluctant to eat cheese.  Fortunately, manufacturers realizing that vegetarianism was not simply a fad but represented an increasingly significant proportion of the population and have created non-animal alternatives. Over 85 percent of cheeses made in Britain and 60 percent in New Zealand use a rennet substitute suitable for vegetarians. Some traditional cheeses dating back thousands of years use vegetable or fungal (microbial) alternatives for coagulation. These include the juices of certain plants, such as thistle and Lady's Bed Straw. Fig juice has also been used to start coagulation.  Rennet helps to break down the curd into a smooth, even consistency, contributing to the texture and flavor. It's important to note that the rennet does not kill the starter; it works alongside it. The starter remains active in the cheese, ready to contribute a great deal later during the ripening process, affecting the cheese's finished flavor.

Cutting, Cooking, Pressing and Brining

The goal of this stage is to concentrate the curd. The method, to cut, cook, press, salt, etc. varies with the cheese being made.

Step 1: The curds are cut to expel excess whey that is trapped within the curd. The size of the curd determines the finished texture of a cheese. Curd size may be small, medium, or large, depending upon the texture called for in particular cheese being made. The smaller the curd is cut, the more whey released, resulting in a firmer, drier cheese with a "tight, dense" texture. The larger the curd, the softer the cheese. In fact, many soft cheeses require little or no cutting of the curd at all.

Step 2: Most cheeses, ones, which will be firmer, textured and aged longer, require reheating of the curds, or to cook them, as cheese-makers would say. During this cooking stage, the curds are also being stirred frequently but gently. Heating the curd and stirring, causes the protein clumps to fuse into tiny strands, thus changing the texture of the curd. Some cheeses require Cheddaring, a method of treating curd to achieve a particular texture in the finished cheese. In this process, used only for Cheddars or Cheddar-type (Colby) cheeses, the curds are piled on top of each other, cut up, pressed together, and then piled up again over heat. This action allows a large amount of whey to be expelled, resulting in a very dense-textured, dry, semi-hard cheese. After Cheddaring, the curds are passed through a mill to mince them into extremely fine pieces before they are pressed into molds).

Step 3: Salting, which follows cooking, also varies with the cheese. Salt dehydrates and slows, or controls, ripening rates, retarding the action of the starter bacteria so that a cheese can be aged for a longer period to achieve the desired flavor and texture. Without salting, cheeses very quickly become over-ripe, sour and mold will develop.

There are four methods of salting a cheese. The salt can be added directly to the curd, by hand. Or the cheese is floated in a brine bath for a few hours or days.  The third method is to rub the surface of the cheese with salt granules, being sure to cover the entire surface. This method produces a hard, dry rind that allows the cheese to ripen from the inside out, producing a strong-flavored, hard cheese. The fourth method is to wash the cheese with a brine-soaked cloth that you store in a brine, not washing between cheese making sessions. At this point, many cheeses are put into a mold and pressed to further remove the whey and to give the cheese its shape. Not all cheeses are pressed. For example, cheeses like Camembert, Brie, Crottin, the curd is hand laded into small cylinder, colander shaped molds, and gravity works to extract the whey. These molds determine the shape of the final product. The harder a cheese is pressed, the firmer the final product will be.

Ripening

The goal of ripening is to ripen the prepared cheese and treat it as needed to produce a cheese that is of an age, texture, flavor, aroma, and appearance true to its type. It is vital that during the ripening stage some of the components of the milk proteins, fat, and carbohydrates break down into simpler, smaller molecules through natural chemical changes to a degree that will result in a balance of flavors in the finished cheese. The breakdown of these molecules is important in the flavor process. Most importantly, ripening is our chance to help nature turn that cheese into the best it can be. Cheese makers do this by controlling humidity, temperature, and the amount of time we allow our cheeses to age. All of these choices, influence the final outcome of our cheeses.