Cheese is one of the most beloved foods around the world. The creamy, tangy, and sharp flavors of cheese bring joy to many meals and snacks.
But how exactly is this delicious dairy product made? Cheese processing is a time-honored craft that transforms milk into the wide world of cheeses we know and love.
A Brief History of Cheese Processing
Humans have been processing milk into cheese for thousands of years. Some of the earliest evidence of cheesemaking dates back to around 8000 BCE. At first, cheese was likely discovered accidentally when stored milk curdled and separated into solids and liquid. Over time, cheesemaking processes became more refined.
Cheese was an important way to preserve nutrition from milk. By removing moisture and shaping the remaining milk solids into cheeses, the nutrients could be stored for longer periods without spoiling. Different regions developed their own distinct cheese varieties depending on the local environment, milk sources, and culture.
Today, cheese processing benefits from modern science and technology while still retaining much of the art and tradition of this ancient food. Standardization and mechanization have enabled the large-scale production of many popular cheeses. At the same time, traditional small-scale cheesemakers use time-honored techniques to craft cheeses by hand.
the Cheesemaking Process
While the details vary for different cheese types, cheese processing involves a basic sequence:
- Treat and prepare the milk
- Culture and acidify the milk
- Coagulate the milk to form curds and whey
- Cut, cook, and process the curds
- Drain the whey
- Salt the curds
- Shape and press the curds
- Age or ripen the cheese
Next, we’ll explore what happens at each step along the way from milk to cheese.
Treating and Preparing the Milk
Raw milk straight from the animal must be treated before cheesemaking. The first step is standardization, adjusting the levels of fat, protein, and other components to specifications.
The milk also goes through pasteurization to kill pathogens and undesirable bacteria by heating. For cheeses made from raw or lightly pasteurized milk, the milk may get a milder heat treatment instead. This preserves more enzymes while still reducing harmful microbes.
After treatment, the milk is cooled to the temperature needed for culturing, around 90°F. The treated milk provides a clean slate for cheese cultures to grow.
Culturing and Acidifying the Milk
Next, starter cultures are added to the milk. This inoculation of the milk kickstarts the cheesemaking process.
Starter cultures are bacteria that convert the milk sugar lactose into lactic acid. This makes the milk gradually turn acidic. A specific cocktail of bacterial cultures creates the signature flavor and texture profile of each cheese variety.
Nonstarter bacteria may also be added for more complexity. The ripening culture slowly lowers the pH and develops cheese flavor.
Coagulating the Milk into Curds
Once the cultures have ripened the milk, coagulation is the next vital step. Coagulants make the proteins in the cultured milk gel and clump together.
Rennet is the most common coagulant used. This enzyme specifically coagulates the milk protein casein, causing the proteins to tangle together into a mass. The lump of milk proteins that form are the curds, and the remaining liquid is the whey.
Other coagulants like acids or plant-based enzymes may also be used. No matter the coagulant, this step transforms the liquid milk into the first semisolid curd mass.
Cutting, Cooking, and Processing Curds
After the mass of curds forms, the curds are cut into smaller pieces. This helps separate curds from whey and release moisture from the curds.
The curds may also be cooked by heating to a target temperature. Cooking makes the curds shrink and compact as more whey is expelled.
Stirring and washing may further process the curd pieces. This develops the texture and reduces acidity. The curds may also be pressed or molded into shapes.
All this cutting, cooking, and processing prepares the curds for whey drainage and creates the desired moisture level.
Draining the Whey
Once the curds are at the right stage, the liquid whey must be drained off fully. This leaves just the semisolid curd pieces behind.
Whey can drain off naturally, but pressing the curds or using molds helps force out more whey quickly. Getting rid of the whey removes moisture and concentrates the milk solids.
Cheddaring may be done for some cheeses like cheddar. The slabs of drained curd are stacked and flipped to press out additional whey.
Salting the Curds
Next, salt is added to the curds for flavor and preservation. Dry salting involves sprinkling salt directly on the curds and mixing evenly.
Another option is brining by submerging the curds or cheese in a saltwater solution. The salt also helps remove even more whey.
Salt affects the activity of enzymes and starter cultures during the aging process.
Shaping and Pressing the Curds
To form the finished cheese, the salted curds must be shaped and pressed to remove even more whey.
Curds can be pressed into molds or forms. Common shapes are wheels and blocks. Pressing gives the cheeses their familiar look.
The pressure compacts the curds together into a cohesive mass while continuing to expel moisture. This prevents gaps or air pockets.
Aging or Ripening the Cheese
Finally, the shaped cheese must be aged or ripened to develop its defining textures, aromas, and flavors.
Aging environments are carefully controlled for factors like temperature, humidity, and air circulation. The duration can range from weeks to years depending on the cheese variety.
Interior mold cheeses are coated in wax or other material. Ripening happens slowly from the interior out. Surface mold cheeses develop natural rinds during ripening.
Enzymes and microbiota transform cheeses during aging through complex chemical changes. These changes create each cheese's characteristic complexity.
Once aging is complete, the cheese is ready for cutting, packaging, and savoring!
Other Key Cheesemaking Steps
Beyond the core process, there are a few other steps that play key roles in many cheeses:
- Salt brine baths: Instead of dry salting, many cheeses get submerged in a saltwater brine bath. The salt solution seasons the cheese and forms a rind.
- Surface treatments: For some cheeses like washed rinds, bacteria are intentionally cultivated on the surface as the cheese ages. This contributes unique flavors and textures.
- Mold spores: Penicillium mold spores are added to create signature blue veining in cheeses like Roquefort and Gorgonzola. The mold grows as the cheese ripens.
- Aroma compounds: Some cheeses have aromatic ingredients like wine, spirits, herbs, or spices added to the curds. This provides signature aromas.
How Different Types of Cheese Are Made
There are countless cheese varieties, and techniques vary widely. But in general, cheeses fall into these basic categories:
- Fresh cheeses like cottage cheese and ricotta have mild flavors and high moisture. They get made quickly with minimal aging.
- Soft cheeses get lightly pressed or ladled into molds without cooking curds. Examples are Brie, feta, and goat cheese.
- Semi-soft cheeses use cooked and pressed curds. Washing rinds and mold growth during aging is common. Mozzarella and Havarti are semi-soft.
- Firm/hard cheeses are cooked at higher heat and pressed to remove moisture. Aged significantly. Includes cheddar, Parmesan, Gruyère.
- Blue cheeses have Penicillium mold spores added so the mold grows veins inside the cheese as it ages. Blue cheese is tangy, creamy, and pungent.
The incredible diversity of cheeses comes down to choices made in the cheesemaking process. everything from the milk, cultures, coagulants, curd handling, and aging conditions can create unique cheeses with different aromas, textures, flavors, and appearances.
The Role of Brine in Cheese Processing
Brine is a saltwater solution that plays a key role in many cheeses through brining, rind formation, and flavor development.
Brining means soaking cheese in brine after the curds are formed. Similar to dry salting, the salt seasons the cheese and draws out more whey. Brining also contributes a distinctive firm yet pliable texture. Many cheeses get partially dried then brined, like feta and halloumi.
During aging, brine supports rind development on surface-ripened cheeses. Washing cheese in brine introduces desirable bacteria to form a protective rind.
Brine also provides signature flavors and aromas. The salt concentration, seasonings, and other ingredients in the brine solution impact the cheese's taste. Brine can contain wine, beer, spices, herbs, pepper, or other flavorings. These infuse the cheese with extra complexity.
Overall, brine is a versatile tool in cheesemaking for texture, rind formation, and flavor. From a quick dip to prolonged aging and washing, brine transforms many cheeses in important ways.
Mechanization in Large-Scale Cheese Production
While traditional cheesemaking is a manual craft, large-scale production today relies heavily on mechanization and automation.
- Milk pasteurization uses continuous heat exchangers and separators to process high volumes of milk efficiently.
- Standardized starter cultures allow consistent, large-batch inoculations.
- Mechanical coagulators quickly coagulate thousands of gallons of milk for curd formation.
- Curd cutters uniformly cut curd into small pieces using rotating blades.
- Curd cooking vats have built-in heaters and temperature control.
- Curd conveyors transport curd for whey drainage, salting, and pressing.
- Brine systems automate the salting process for high volume.
- Molding and pressing machinery shape and package cheeses.
Automated aging rooms control temperature, humidity, and airflow for optimal ripening. While technology enables efficient high-volume cheese production, the basic steps of cheesemaking remain largely the same.
The Craft of Artisan Cheesemaking
In contrast to mass production, artisan cheesemaking follows traditional techniques, handcrafting cheeses in small batches. Although labor-intensive, this meticulous approach allows artisans to control every step.
Key hallmarks of artisan cheese production include:
- Raw or minimally processed milk with enzymes intact for enhanced ripening
- Traditional starter cultures like well-preserved whey cultures passed down for generations
- Natural coagulants like traditional animal rennet provide authentic flavor
- Hand-cutting and hand-stirring of curds
- Manual pressing and molding of curds to form wheels
- Natural rind development during aging for signature texture and appearance
- Aging in meticulously controlled cellars
- Affinage by skilled cheesemakers to monitor and care for cheeses as they age
This hands-on process allows cheesemakers to respond and adapt their practices based on minute differences between cheese batches. The extra attention coaxes the fullest flavors and finest textures from each wheel.
FAQs
How is milk turned into cheese?
Milk is turned into cheese through a series of steps that coagulate milk proteins into curds, drain liquid whey, process the curds, salt them, shape them, and age the cheese. Adding cultures and rennet causes curdling. Further whey removal, shaping, and aging transforms soft curds into solid, flavorful cheeses.
What process makes Swiss cheese have holes?
The holes or "eyes" in Swiss cheese come from carbon dioxide gas bubbles produced by Propionibacterium bacteria during aging. The bacteria ferment lactic acid into CO2 which forms pockets in the cheese. The cheeses are moved to warmer rooms several weeks into aging to allow this secondary fermentation.
What is the white mold on brie cheese?
The edible white rind on brie cheeses consists of Penicillium camemberti mold. Cheesemakers spray or rub this mold onto the surface of young brie cheeses. As the cheeses age, the mold grows to form the characteristic white fuzz on the rind surrounding the buttery interior paste.
How does blue cheese get blue veins?
The blue-green veins in cheeses like Roquefort and Gorgonzola come from Penicillium mold. By inserting needles to form air channels and inoculating with mold spores, cheesemakers allow Penicillium mold to grow long blue veins throughout the cheese as it ages. The mold contributes to the pungent flavor.
What is the difference between raw and pasteurized cheese?
Raw milk cheese is made from unpasteurized milk. It retains more diverse enzymes and microbiota for stronger ripening and bolder flavors. Pasteurized milk cheese is made from heat-treated milk to reduce pathogens. It ages more mildly with simpler flavors but can be made safely on a large scale.
Conclusion
Whether produced using old-world artisan methods or modern large-scale mechanics, cheese processing is a phenomenon of science and craftsmanship.
The subtleties of each step combine to create everything from fresh mozzarella to pungent Epoisses.