The Importance Of Measuring The pH Of Cheese


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Measuring the pH of cheese is an essential step in the cheese-making process. It is important for determining the right time for cutting the curd, controlling the growth of bacteria, ensuring the safety of the cheese, and improving the quality of the cheese. By using a pH meter to measure the pH levels of cheese, cheese-makers can produce high-quality, safe, and delicious cheese.

Cheese is one of the most beloved and versatile foods in the world. From creamy brie to sharp cheddar, there’s a cheese for every palate. But did you know that the pH level of cheese can greatly affect its flavor, texture, and safety? That’s right – measuring the pH of cheese is essential for ensuring that it’s not only delicious but also safe to eat.

Without proper pH control, cheese can spoil quickly, develop harmful bacteria, and lose its unique flavor profile. In this article, we’ll explore the importance of measuring the pH of cheese and how it impacts the final product. Whether you’re a cheese expert or just starting out, understanding the role of pH in cheese-making is key to creating and enjoying the perfect slice of cheese.

How Is Cheese Made?

The process of making cheese is actually quite intricate and involves several steps. The first step in making cheese is to acidify the milk. This is done by adding a starter culture of bacteria, which lowers the pH of the milk. The bacteria consume lactose, the sugar present in milk, and produce lactic acid, which lowers the pH.

During the cheese-making process, the optimal temperature is 5.1 and 5.9. Once the pH has been lowered, an enzyme called rennet is added to the milk. Rennet causes the milk to coagulate, or clump together, forming a curd. The curd is then cut into small pieces and heated. This causes the curd to separate from the whey, which is the liquid part of the milk. The curd is then drained and pressed, which removes even more whey. The type of cheese you are making determines how long the curd is drained and pressed.

Once the curd has been drained and pressed, it’s time to age the cheese. The length of time for aging depends on the type of cheese being made. During the aging process, the cheese develops its characteristic flavor and texture. The pH of cheese is an important factor in determining the final flavor and texture of the cheese. Cheeses with a lower pH have a sharper flavor and firmer texture, while cheeses with a higher pH have a milder flavor and a softer texture.

Why Is Measuring The pH Of Cheese Important?

Measuring the pH of cheese is a crucial step in the following cheese-making processes.


The pH level of cheese plays a crucial role in the ripening process. As cheese ages, it undergoes a series of chemical and physical changes that are influenced by a variety of factors, including pH. The pH scale ranges from 0 to 14, with a pH of 7 being neutral. Cheese typically starts out with a pH between 5.0 and 6.5, but as it ages, the pH begins to drop. This drop in pH is due to the production of lactic acid by bacteria in the cheese.

The pH level affects the texture, flavor, and aroma of the cheese during the ripening process. When the pH drops, the cheese becomes firmer and develops a sharper, more pronounced flavor. This is because the bacteria responsible for producing lactic acid also produce enzymes that break down the proteins and fats in the cheese. As the cheese ages and the pH drops, these enzymes become more active, which leads to a breakdown of the cheese’s structure and the development of complex flavors and aromas.

However, if the pH drops too low, it can have a negative impact on the cheese’s quality. If the pH drops below 4.5, the cheese can become too sour and acidic, which can make it unpalatable. Conversely, if the pH remains too high, the cheese may not ripen properly and can develop off-flavors or spoil. 

Salt Uptake

When the pH levels of cheese are low, the salt uptake of cheese increases, making it saltier. While, when the pH levels of cheese are high, the salt uptake reduces, resulting in a less salty taste.

The reason why pH affects the salt uptake of cheese is because of the way salt interacts with the protein molecules in cheese. Salt ions are attracted to the negatively charged protein molecules, which causes the proteins to become more compact. This compaction increases the cheese’s density, resulting in a saltier taste. However, when the pH levels of cheese are high, the protein molecules become less negatively charged, causing the salt ions to repel the proteins. This repulsion results in a reduction of salt uptake and a less salty taste.

Texture & Flavor

Cheeses with a higher pH level tend to have a softer texture and a more buttery and mild flavor like ricotta. However, cheeses like feta with a lower pH level tend to be firmer, sharper, and tangier. The texture comes from calcium. Calcium acts as an elastic glue in cheese, so cheeses that contain a higher amount of calcium will be more elastic than cheeses with lower calcium levels. When cheese curd is acidified, the hydrogen ions displace the calcium ions until the cheese maker decides to drain the whey off. The importance of measuring pH in cheese-making is also significant as it helps to determine the right time for cutting the curd, which is a critical step in the cheese-making process.


The pH of cheese also determines how moist it is. If the pH level is too high, the cheese will lose moisture, and the texture will become brittle and crumbly. On the other hand, if the pH level is too low, the cheese will become overly moist, and this can result in a cheese that is too soft and mushy.

Most cheeses have a pH level between 5.2 and 5.5, which allows for the proper balance of moisture and texture. When the pH level is within this range, the cheese will have the right amount of moisture and will be able to age properly.


The microflora of cheese is made up of various bacterial strains that contribute to the flavor, texture, and aroma of the cheese. These bacteria react differently to changes in pH levels, and this affects their population and activity in the cheese.

Cheese with a pH below 5.2 is considered acidic, and this favors the growth of lactic acid bacteria. These bacteria produce lactic acid, which lowers the pH level even further, creating an environment that is hostile to other bacteria. This leads to the production of hard, acidic cheeses like cheddar and Parmesan.

On the other hand, cheese with a pH above 6.5 is considered basic, and this favors the growth of other bacterial strains, such as Pseudomonas and Enterobacteriaceae. These bacteria produce ammonia, which raises the pH level of the cheese, creating a softer, more pungent cheese like Brie or Camembert.

Pathogen Growth/Survival

The pH level of cheese is a crucial factor in determining the growth and survival of pathogens. Pathogens such as Salmonella, Listeria, and E. coli require a neutral or slightly alkaline pH level to grow and multiply. Therefore, cheese with a pH level below 4.5 is considered relatively safe from pathogen growth.

On the other hand, cheese with a higher pH level, closer to 5.5, is more conducive to pathogen growth. For example, blue cheese typically contains Staphylococcus equorum and Enterococcus durans in the cheese rind. This is because the higher pH level allows bacteria to thrive and multiply rapidly. Additionally, some pathogens are more tolerant of acidic environments and can survive in cheese with a lower pH level.

You can carefully monitor the pH level of your cheese to ensure that it remains within the safe range. Various techniques such as adding specific cultures or adjusting the temperature to achieve the desired pH level are also used. Additionally, cheese that is aged for an extended period can naturally become more acidic, making it less hospitable to pathogens.

Rennet Coagulation Properties

If the pH of the milk used to make the cheese is too high or too low, it can affect the rennet coagulation properties of cheese. Rennet is an enzyme that is added to milk to coagulate it and form cheese curd. The ideal pH level for rennet coagulation is around 6.0.

When the pH of the milk is too low, it can cause the rennet to coagulate too quickly, resulting in a firm, rubbery texture. On the other hand, if the pH is too high, it can cause the rennet to coagulate too slowly or not at all, resulting in a soft, slimy texture.

How To Measure The pH Of Cheese?

The best way to measure the pH of cheese is a pH meter. The pH meter provides accurate measurements of the pH levels of the cheese, and this information can be used to make adjustments in the cheese-making process. 

Different Cheeses & pHs

Different types of cheese have varying pH levels. Generally, cheese has a pH range of 4.5 to 7. Below are some common cheeses and their ideal pH levels.

Type Of Cheese(s)pH Value 
Cream cheese, Feta, Cottage Cheese4.6-4.9
Gouda, Mozzarella, Cheddar, Parmesan, 5.1-5.4
Gruyere, Swiss, Fresh Mozzarella5.5-5.7
Blue Cheese, Brie, Limburger, Queso Fresco6.2-6.5


It is essential to monitor the pH of cheese during the cheesemaking process to ensure quality and consistency. The pH plays a crucial role in determining the texture, flavor, and aroma of the cheese. Moreover, it also affects the growth of bacteria and other microorganisms that can spoil the cheese or cause foodborne illnesses. Therefore, you must use precise pH meters and maintain the appropriate pH range for each type of cheese. 

If you have any questions regarding measuring the pH of cheese or what pH meters we have to offer, do not hesitate to contact the world-class team at Atlas Scientific.

pH Probes & Sensors

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