Cheese: The Science Behind Production, Flavor and Texture

Cheese: The Science Behind Production, Flavor, and Texture

Introduction

Assorted varieties of cheese

Cheese is more than just a culinary staple—it’s a product of intricate biochemical transformations, shaped by culture, tradition, and science. Across continents, cheese plays a significant role in both local diets and global trade, with hundreds of varieties ranging from fresh and mild to aged and intensely flavorful. While cheese-making has ancient roots, the science behind how cheese evolves during aging, how its flavor develops, and how it’s kept safe for consumption remains a topic of ongoing study and regulation.

In this project, we explore core aspects of cheese: the cheese making process and the chemistry behind flavor and texture. By examining how enzymes and microbes influence texture and taste over time, and identifying the key compounds responsible for flavor, we aim to uncover the fascinating science that lies beneath the surface of every cheese wheel. Our research bridges food science and microbiology to highlight what makes cheese both delicious and safe.

Processing

The Cheese-Making Process

Cheese making process

Cheese making is a multi-step process that transforms milk into a concentrated, preserved, and flavorful product through controlled fermentation, coagulation, and curd treatment. It begins with fresh, high-quality raw milk, which is often pasteurized to reduce harmful microorganisms and ensure a consistent starting point for fermentation. Starter cultures—lactic acid–producing bacteria—are added to ferment lactose into lactic acid, lowering the pH and preparing the casein proteins for coagulation. In many cheese varieties, a coagulant such as rennet (containing the enzyme chymosin) is then introduced. This enzyme hydrolyzes κ-casein, altering the micelle structure from calcium-stable to calcium-sensitive, allowing them to aggregate and form a gel network that traps fat and water.

Once the curd forms, it is cut into cubes to promote whey expulsion. The size of the cut curds is a key factor—smaller curds lose more moisture and lead to firmer cheeses, while larger cuts retain more whey, producing softer textures. The curds are then gently heated (“cooked”) to around 38 °C, which accelerates lactic acid production and further contracts the curd, releasing more whey.

After cooking, the whey is drained, and the curds may undergo matting and cheddaring—a process where curd slabs are stacked, turned, and restacked to align texture and drive out additional whey. Cheddared curds are milled into smaller pieces, then salted. Beyond enhancing flavor, salt controls microbial growth, draws out excess moisture, and creates favorable conditions for enzymatic activity during ripening. In some cheeses, salting also influences the final texture by regulating protein breakdown and moisture retention.

The salted curds are then pressed into molds, a step designed to knit them into a cohesive body and expel residual whey. Proper pressing results in a smooth, uniform texture, while inadequate pressure can leave visible curd junctions, causing a crumbly and uneven product. Pressing times and pressures vary depending on the cheese type, but the goal remains consistent: to create a stable internal structure that will withstand aging. This stage also shapes the cheese, preparing it for storage under controlled ripening conditions.

Once molded, the cheeses enter the curing and ripening stage, where time, temperature, and humidity are carefully monitored—commonly around 2 °C and 85% relative humidity for aged cheeses like Cheddar. Fresh cheeses such as cottage or cream cheese undergo minimal or no ripening, whereas aged varieties like Gouda or Parmesan can mature for months or even years. During ripening, enzymes from the starter cultures, rennet, and secondary microflora gradually break down proteins into peptides and amino acids, and fats into free fatty acids, generating the complex aromas, flavors, and textures characteristic of each cheese type. This biochemical transformation distinguishes the soft, creamy body of Brie from the firm, crumbly texture of an aged Cheddar, making ripening the final and perhaps most defining stage of cheese making.

Flavor and Texture

Flavor and Texture: The Chemistry Behind It

Texture:

The texture of cheese is primarily determined by the behavior of milk proteins, especially casein, during the coagulation and aging process. In cheese-making, casein micelles form a gel structure that traps fat and water, resulting in the curd formation central to cheese texture. Coagulation is typically initiated by rennet enzymes (proteases), which break down κ-casein and promote micelle aggregation. This process transforms liquid milk into a semi-solid mass with specific textural characteristics.

Moisture content, how the curd is handled (such as cutting and pressing), and aging time all affect whether cheese is soft, semi-soft, or hard. High moisture content tends to soften the cheeses, so the moisture content must be closely monitored to ensure the target softness is achieved. During ripening, enzymes from the cheese itself and from microbes break down casein proteins, which softens the cheese over time. These enzymes also help develop the flavor and texture in aged cheeses.

Homogenization and emulsifying properties of milk proteins also affect fat distribution in the curd, indirectly influencing texture. According to Fox et al., changes in milk composition and processing parameters allow producers to control the rheological properties of cheese, enabling consistent production of specific texture profiles.

Flavor:

The flavor of cheese is developed through microbial metabolism and enzymatic activities during the process of both fermentation and ripening. Microorganisms such as acid bacteria, Propionibacterium, and molds are essential in the processes, as they break down components like milk proteins, fats, and sugars into many different compounds that form the flavor of cheese.

Proteolysis is the enzymatic breakdown of casein proteins, which produces peptides and free amino acids. And then, these amino acids produced can undergo deamination and decarboxylation. The reactions release volatile compounds such as amines, aldehydes, ammonia, and sulfur-containing molecules, which will provide cheeses for their distinctive aroma and pungency.

Lipolysis occurs when microbial lipases hydrolyze milk triglycerides into free fatty acids. And the fatty acids are further converted into ketones, lactones, esters, and other volatile derivatives, therefore greatly increasing the flavor complexity of cheese.

During fermentation, lactose is converted into organic acids such as lactic acid and propionic acid. These acids change the acidity and texture of the cheese. In addition, carbon dioxide produced by Propionibacterium forms the holes in Swiss cheese and also creates its nutty taste.

Environmental conditions can also play a major role in creating cheese. For instance, temperature and humidity control enzymatic activity and microbial growth, which directly shape flavor development.

Carbohydrates, triglycerides, and casein are metabolized by specific microorganisms and enzymes into volatile compounds. Amino acid breakdown forms branched-chain, aromatic, and sulfur-containing compounds. Fatty acid derivatives produce esters and lactones. Together, these compounds create the range of flavors found in different cheeses.

Research Findings and Conclusion

The research highlights cheese as a product of the unique balance between biochemical reactions and microbial processes. The process of making cheese begins with an intricate preparation of quality milk followed by coagulation, cutting and moisture regulation. The aggregate process of cheese preparation lays the foundation for the texture, a central and key component to cheese, while the flavor profile is primarily determined by enzymatic reactions during fermentation.

Our findings maintain that moisture and aging is key in determining the relative softness of cheese, and as such, cheese must be carefully monitored for moisture content and enzymatic processes throughout production. In terms of flavor, proteolysis was found to be a primary determinant for the different flavor profiles and aromas which characterize cheeses. Through this process, casein proteins are broken down into constituent amino acids which experience deamination and decarboxylation reactions, and as such, release compounds that make up the distinctive pungency of cheese.

Modern day cheeses are the result of the collaboration between age-old tradition and modern microbiology. By managing the delicate balance between classic processing methods and understanding microbial reactions, cheese is crafted with quality. The continuous harmony of both science and craftsmanship ensures that the cheese-making process and flavors will continue to evolve while preserving the classic methods of cheese-making.

Potential Exam Question

What kind of factors contribute to a relatively softer cheese?

A) Low moisture content and low enzymatic activity

B) Low moisture content and high enzymatic activity

C) High moisture content and high enzymatic activity

D) High moisture content and low enzymatic activity

Correct answer: High moisture content and high enzymatic activity

This question is effective as it ensures students understand the importance of moisture content and enzymatic activity in not only cheese-making, but also other fermentation processes as well. Microbes, enzymes, and moisture play a key role in the transformation of texture and flavor, and this knowledge can also be applied to other principles of FNH, such as the careful regulation of moisture and temperature in processing and fermentation.