The Chemistry Behind Cheese: Ingredients And Process

Cheese is a dairy product made from the milk of mammals such as cows, buffalo, goats, and sheep. The process of making cheese involves six steps: acidification, coagulation, separating curds and whey, salting, shaping, and ripening. The first step is to add a starter culture to the milk, which changes lactose into lactic acid, altering the acidity level and beginning the process of turning milk from a liquid to a solid. An enzyme called rennet is then added to the milk to further encourage solidification. The solid part of the milk is called curd, and the liquid is called whey. The curds are then cut, and the smaller the curds, the harder the cheese. The whey is then drained away, and salt is added for flavour and preservation. The cheese is then put into a basket or a mould to form its shape and pressed with weights or a machine to expel any remaining liquid. Finally, the cheese is left to ripen until it reaches optimal ripeness.

Milk

The fresher the milk, the better the cheese. Farm-fresh milk is ideal, but store-bought milk can also be used, as long as it is as fresh as possible. Milk that tastes sour or "off" should not be used. Milk can be pasteurised to kill bacteria and make it last longer. This is done by heating the milk to 145°F, holding this temperature for 30 minutes, then cooling it quickly to 40°F.

The process of turning milk into cheese involves six important steps: acidification, coagulation, separating curds and whey, salting, shaping, and ripening. During the acidification stage, a starter culture is added to the milk to change lactose (milk sugar) into lactic acid. This changes the acidity level of the milk and begins the process of turning it from a liquid into a solid.

The coagulation stage involves adding an enzyme called rennet, which can be derived from either animal or vegetable, to further encourage the milk to solidify. As the milk solidifies, it forms curds (the solid part) and whey (the liquid). The curds are then cut, which further encourages them to expel whey. Generally, the smaller the curds are cut, the harder the resulting cheese will be.

Once the curds are ready, the whey is drained away, and salt is added for flavour and as a preservative. The cheese is then put into a basket or a mould to form it into a specific shape and pressed with weights or a machine to expel any remaining liquid. Finally, the cheese is left to ripen until it reaches optimal ripeness. The amount of time it is left to ripen depends on the type of cheese and the cheesemaker's desired outcome, ranging from several months to several years.

Rennet

Animal rennet is derived from the lining of the fourth stomach of a calf, which contains both rennin and pepsin enzymes. This form of rennet has been used for centuries and is the most traditional form. The use of rennet in cheesemaking dates back to ancient times, with some sources suggesting that cheese was discovered when milk was stored in a container made from the stomach of an animal, causing the milk to turn into curds and whey due to the rennet in the stomach lining.

The choice between animal and vegetable rennet is typically based on personal preference. Liquid rennet is the most popular form as it is easy to measure and mixes into milk quickly. It should be stored in the refrigerator and will last for 4-12 months. Rennet tablets have the longest shelf life, lasting up to five years in the freezer. They need to be crushed and dissolved in water before being added to milk. Powdered rennet has a shelf life of about one year and is best stored at 38-45°F. This form is suitable for hotter climates as it is less sensitive to temperature fluctuations.

Bacteria

Starter cultures, which are friendly bacteria, are often added to the milk to facilitate this acidification process. These bacteria ferment the lactose in the milk, increasing acidity levels and dictating the moisture and mineral content of the curds. The specific type of bacteria used, as well as the temperature at which they are added, will influence the taste, texture, and characteristics of the final cheese product.

There are two basic categories of starter cultures: Mesophilic and Thermophilic. Mesophilic cultures require low heat and cannot survive at higher temperatures, while Thermophilic cultures thrive at high temperatures and will not function properly until those temperatures are reached. Within these two categories, there are different types of cultures, and a combination of two to four cultures is often used in cheesemaking.

In addition to their role in acidification, bacteria also contribute to the development of flavour and texture during the ripening or affinage process. This is when the cheese is left to age, allowing microbes and enzymes to transform its texture and intensify its flavour. The specific bacteria present during this stage will depend on the type of cheese being made and the desired outcome. For example, ambient moulds in the air can give the cheese a distinct flavour, while other cheeses may have bacteria introduced through spraying, injecting, or the presence of a natural rind.

Overall, bacteria play a fundamental role in cheesemaking, from the initial acidification of milk to the development of flavour and texture during ripening. The specific types and combinations of bacteria used will vary depending on the type of cheese being produced, resulting in the vast array of cheeses available today.

Salt

The amount and type of salt used, as well as the method of addition, can vary depending on the specific cheese being made. For example, mozzarella is bathed in a vat of brine, while other cheeses may be rubbed with dry salt or soaked in a damp cloth that has been immersed in brine.

In addition to its functional and flavour-enhancing properties, salt can also influence the texture of the cheese. When used in the right proportions and combined with other ingredients, salt can contribute to the desired texture, such as a firm or crumbly mouthfeel.

Furthermore, salt is involved in the formation of a natural rind on the cheese. This rind not only adds to the appearance of the cheese but also helps to protect the product during storage and transportation, further extending its shelf life.

Herbs and spices

Herb and Cheese Pairings

Blue cheese, with its strong flavour, pairs well with pungent herbs such as parsley, sage, garlic, thyme, and cracked black pepper. Brie, a creamy cheese, is best complemented by thyme, chives, basil, tarragon, and parsley. Goat's cheese goes well with dill, and feta pairs well with basil, oregano, and red pepper flakes. Monterey Jack, a mild cheese, is a great canvas for herb experimentation, and pairs well with dill, oregano, and sage. Mozzarella is a classic pairing with basil, and also works well with rosemary. Other good herb and cheese pairings include ricotta and thyme or parsley, and Swiss cheese with dill or chives.

Using Herbs and Spices in Cheese Dishes

Health Benefits of Herbs and Spices in Cheese

Combining herbs and spices with cheese not only enhances flavour but can also provide additional health benefits. Many herbs contain antioxidants and anti-inflammatory compounds that can boost the nutritional value of cheese dishes. For example, rosemary contains carnosic acid, a potent antioxidant, while garlic provides immune-supporting allicin compounds. Traditional Mediterranean combinations of cheese with oregano and thyme offer both antimicrobial properties and digestive benefits, while the addition of black pepper can enhance the bioavailability of cheese's nutrients.

Frequently asked questions