Cheese has embedded itself into culinary traditions across the globe. In the United States, the consumption per capita of cheese and yogurt has significantly increased during the past 50 years, from 18 lbs/person and 2 lbs/person in 1975 to 42 lbs/person and 14 lbs/person in 2022 for cheese and yogurt, respectively (USDA). However, the consumption of fluid milk has decreased during the same period, from 247 lbs/person in 1975 to 130 lbs/person in 2022 (Figure 1).
Figure 1. Consumption per capita (lbs)
From the tangy flavors of aged cheddar to the creamy smoothness of fresh mozzarella, cheese is more than just food; it’s an art form. Cheese production in modern factories is a blend of tradition and cutting-edge technology. To meet increasing consumer demand, once an artisan craft is practiced on farms, cheese is produced in a highly controlled industrial process. Understanding the cheese production process offers a glimpse into a craft that combines science, technology, and techniques. This article will explore the journey of milk through the cheese factory, explaining each step in detail and how manufacturers maintain the quality, safety, and consistency of their products.
The basics of cheese production
Cheese making involves ingredients and equipment, all working together to transform milk into a symphony of flavors and textures.
Key ingredients:
Each factory and each type of cheese use specific ingredients, but let’s describe the essential ingredients necessary for cheese production.
- Of course, milk is the foundation of any cheese. While milk from cows is commonly used, cheese can also be produced from goats or sheep. Each type of milk has unique flavor characteristics.
- Bacteria or starter cultures are essential in developing flavor and the desired taste. These bacteria convert lactose into lactic acid.
- Rennet is an enzyme crucial for coagulating milk and forming curds, the building blocks of cheese.
- Salt helps preserve cheese and control moisture and is a flavor enhancer.
Essential equipment
In a factory setting, technology has transformed the equipment used in dairy factories. However, the three essential equipment for successful cheese-making are cheese vats for holding and heating milk, molds for shaping the cheese into its final form, and thermometers to control the temperature for each process step.
The cheese-making process
1. The foundation: milk selection and preparation
Making cheese begins with selecting high-quality milk, the fundamental ingredient. Cheese factories source milk from dairy farms, often from cows, goats, or sheep, depending on the type of cheese being produced. Milk types will significantly influence the flavor and texture of the cheese.
Upon arrival at the factory, milk undergoes several steps to ensure it is safe and ready for cheese-making.
Rigorous testing is the first step in ensuring it meets strict safety and the necessary standards for cheese making. The testing includes checking for the presence of contaminants, ensuring the proper fat content, and verifying its freshness. Samples are also tested for bacteria levels and pH.
The next step is pasteurization. Milk is heated to a specific temperature, usually around 72oC or 161oF, for 15-20 seconds, followed by rapid cooling. The process kills harmful bacteria without compromising its essential proteins and enzymes. Pasteurization ensures the safety of the final product while also giving factories more control over the cheese’s final taste and texture.
Standardization is the adjustment of milk’s fat content to create a consistent product. Skin milk or cream is added to ensure the correct fat ratio, which varies depending on the type of cheese being produced. Standardization is critical because fat content variations can affect the final product’s texture and flavor.
2. Acidification by setting the stage for curdling
Bacteria cultures, often referred to as starter cultures, are added to milk. These bacteria convert lactose into lactic acid, lowering the milk’s pH and creating the conditions necessary for curdling. The types of cultures depend on the types of cheese. For instance, mesophilic cultures are used for cheddar and gouda, while thermophilic cultures are used for cheese like Parmesan or mozzarella.
Fermentation time is the process of leaving milk to ferment by allowing the bacteria to do their work. The fermentation time depends on the type of cheese. Short fermentation produces milder cheeses, while longer fermentation times produce more complex flavors.
3. Coagulation by turning milk into curd
Once the milk is sufficiently acidic, it’s time to add rennet, an enzyme that causes it to coagulate, forming curds. Rennet causes the proteins in milk (mainly casein) to clump together, forming curds.
After adding the rennet, the milk thickens and becomes a gel-like substance. To control the curd formation, dairy factories use temperature control and timing to achieve the desired curd texture. Once the curd has formed, it is cut into smaller pieces using wire cutters or blades. The cheese’s final texture and moisture content depend on the curds’ size. Larger curds hold moisture and produce softer cheeses, while smaller curds release more whey and produce firmer cheeses.
4. Cooking and stirring the curds
After cutting, the curds are gently heated and stirred. This step helps release additional whey and firms up the curds. Whey, a byproduct of cheese making, can be used for various purposes, including producing whey-based products. The cooking step is crucial in determining the final flavor and texture of the cheese. The temperature and duration of cooking vary by cheese type. For example, softer cheeses like Brie or Camembert are cooked at lower temperatures, while harder cheeses like Cheddar or Parmesan require higher temperatures.
In a factory setting, temperature control is critical for consistency. Automated systems carefully regulate the heat to ensure the curds reach the right firmness. A slow and even heating process is necessary to avoid overcooking or undercooking. While heating, curds are continuously stirred to prevent them from clumping together and to ensure uniform moisture removal. The stirring speed and duration are carefully controlled to avoid breaking the curds too much.
5. Whey removal and draining
In an industrial setting, machines help efficiently drain the whey from the curds. In mechanical draining, curds are transferred to perforated molds or stainless-steel draining tables, which are mechanically pressed to remove whey. In large-scale factories, conveyor belts and automated systems streamline this process.
6. Salting: Enhancing flavor and preservation
Salt is added to the cheese to enhance flavor, control moisture, and aid in preservation. In factories, salt is added directly to the curds or applied through a brining process, where the cheese is soaked in a saltwater solution. Dry salting is more common for hard cheeses like cheddar, while brining is typical for cheeses like feta or mozzarella. Factories use precise equipment to ensure uniform salt distribution.
7. Molding and Pressing
After salting, the curds are placed into molds, which give the cheese its final shape. Factories use hydraulic presses to apply pressure, compacting the curds and expelling any remaining whey. The amount of pressure applied varies depending on the type of cheese. For some cheeses, molds are used to form blocks or wheels, while others, like blue cheese, require special molds with air holes to allow cultures to develop inside.
Depending on the desired texture and firmness, pressing times can range from a few hours to a full day. Automated systems in factories can handle multiple cheese wheels simultaneously, applying consistent pressure for optional results.
8. Aging or ripening
Once pressed and molded, many cheeses require aging to develop flavor and texture. Aging or ripening involves storing the cheese in controlled environments with regulated temperature and humidity. In large factories, aging rooms, also called affinage rooms, store thousands of wheels or blocks of cheese. Automated systems monitor the temperature (around 10-12oC or 50-55oF) and humidity (75-90%) to create the perfect conditions for ripening.
During aging, various chemical and biological processes take place, resulting in the development of complex flavors, aromas, and textures. Microbes and enzymes in the cheese break down fats and proteins, creating flavors characteristic of mature cheese. The length of aging varies depending on the type of cheese. Some cheeses are aged for weeks, while others, like Parmesan, may be aged for years.
9. Packaging and distribution
Once the cheese has reached its desired maturity stage, it is packaged for distribution. The packaging can vary depending on the type of cheese and the intended market. Some cheeses are wrapped in plastic or foil, while others are packaged in wooden boxes or specialty containers. In a factory setting, the cheese is often cut into specific sizes, vacuum-sealed, and labeled.
To cut large wheels or blocks into retail-sized portions, factories use machines. The cutting is done in sterile conditions to ensure the cheese remains uncontaminated. After portioning, cheese is vacuum-sealed or wrapped to prevent spoilage. Automated labeling machines apply barcodes and other essential information, such as cheese variety and nutritional content. The packaged cheese is then distributed to retailers, wholesalers, or consumers.
In conclusion, cheese production is a complex process that involves a series of carefully controlled steps. From selecting milk to packaging the final products, each stage plays a vital role in determining the quality and characteristics of the cheese. The diversity of cheese types is a testament to the versatility and adaptability of this ancient craft.
