The Science of Cheese pH and the Alkaline Myth
Understanding why cheese is typically acidic requires a look into the core process of cheesemaking. For cheese to form, milk must be coagulated, and a key step in this is acidification. Cheesemakers add a starter culture of bacteria to the milk, which ferments the lactose (milk sugar) into lactic acid. This accumulation of lactic acid causes the milk's pH to drop, leading to the formation of curd and the distinctive tangy flavors in many cheeses. The final pH depends on factors like the type of bacteria used and the aging process.
Why Most Cheeses Are Acidic
- Bacterial Fermentation: Starter cultures produce lactic acid from milk's lactose, which lowers the pH from milk's near-neutral starting point of 6.7.
- Calcium Interaction: The acid helps to strip calcium from casein proteins. The higher the acidity (lower pH), the more calcium is lost in the whey, resulting in a firmer, more crumbly texture.
- Flavor and Safety: The low pH inhibits the growth of harmful pathogens and allows the cheese's unique flavor to develop during aging.
The Flawed Premise of the Alkaline Diet
The concept of an "alkaline diet" is based on the idea that certain foods can alter the body's pH balance to improve health. This theory, however, is a widespread misconception. The human body has sophisticated regulatory systems, primarily involving the kidneys and lungs, to maintain a very narrow and stable blood pH range of 7.35 to 7.45. While diet can influence urine pH, it does not have a significant impact on blood pH. This means that categorizing cheese as "alkaline-forming" or "acid-forming" in the body has little to no scientific basis regarding overall health. The health benefits often associated with the diet come from eating more whole, plant-based foods, not from a change in body pH. For more on this, read Healthline's evidence-based review on the topic Healthline.
Are Any Cheeses Actually Alkaline? A Look at Specific Varieties
While most cheeses are acidic, some varieties finish with a higher pH than others due to their unique ripening processes. These are the cheeses that can be considered less acidic or, in some cases, can approach a near-neutral pH.
Blue and Mold-Ripened Cheeses: The pH-Balancing Act
Many mold-ripened and blue cheeses defy the typical acidic cheese trend. These cheeses start with a low pH, just like others, but a unique phenomenon occurs during aging. The molds, such as those from the Penicillium family, metabolize the lactic acid produced earlier in the cheesemaking process and also produce ammonia. This process increases the cheese's pH over time, bringing it closer to neutral. Some blue cheeses like Roquefort and Gorgonzola can reach a pH of 6.0–7.0. Similarly, surface-ripened cheeses like Camembert can have a final pH around 6.5–7.0, with the rind often becoming even more alkaline.
Cheeses with a Higher-than-Average pH
Besides the mold-ripened varieties, several other cheeses have a relatively high pH, making them among the least acidic options:
- Ricotta: A fresh cheese that generally has a high pH, ranging from 5.7 to 6.3.
- Processed Cheeses: American cheese typically has a pH between 5.5 and 6.0.
- Washed-Curd Cheeses: Varieties like Gouda and Swiss have a higher pH, often in the 5.5–5.8 range, because some of the lactose is washed out during production, resulting in less lactic acid being produced.
Understanding the Acidic Nature of Dairy
While some claim certain milk products might be alkaline-forming, such as raw goat's milk or plant-based milks, the reality for cheese is different. The production process itself is fundamentally acid-driven. It is the action of bacteria, not the milk's inherent properties, that dictates the final pH. This ensures the correct texture, flavor development, and safety of the final product.
Cheese pH Comparison Table
| Cheese Type | Typical pH Range | Characteristics |
|---|---|---|
| Blue Cheese | 6.0 – 7.0 | pH increases during aging due to mold metabolism. |
| Camembert / Brie | 6.0 – 7.0 | Surface-ripening process increases pH towards neutral. |
| Ricotta | 5.7 – 6.3 | Fresh, high-pH cheese. |
| Emmental / Swiss | 5.6 – 5.8 | Washed curd process leads to higher pH. |
| Gouda | 5.3 – 5.5 | Semi-hard, washed-curd cheese. |
| Cheddar | 5.1 – 5.4 | Hard, aged cheese with classic tangy acidity. |
| Mozzarella | 5.2 – 5.4 | Made with quick acidification. |
| Feta | 4.6 – 4.9 | Fresh, highly acidic cheese. |
Factors Affecting Cheese Acidity
The acidity of cheese is not a single, fixed value and can be influenced by several factors throughout its lifecycle:
- Ripening and Aging: For mold-ripened and washed-rind cheeses, the ripening process directly increases the pH over time as mold activity neutralizes acid.
- Manufacturing Method: Cheeses with a washed curd (like Gouda) have a higher pH than those with an unwashed curd (like Cheddar) because the washing process removes lactose that would otherwise be converted to lactic acid.
- Moisture Content: Cheeses with higher moisture content often have a higher pH, as seen in fresh cheeses like ricotta.
- Calcium Content: The amount of calcium present can buffer the pH. Higher calcium retention is associated with higher pH.
Conclusion: The Final Verdict on Alkaline Cheese
To conclude, there is no common, naturally produced cheese that is alkaline. The cheesemaking process is fundamentally dependent on creating an acidic environment. However, certain cheeses, particularly soft-ripened types like Brie and blue cheeses like Gorgonzola, undergo a ripening process where microbial activity raises their pH to near-neutral levels, making them the least acidic cheeses available. The idea that consuming these or any food can make the body alkaline is a nutritional myth, as the body’s pH is tightly controlled and not significantly altered by diet. For those concerned with acidity, opting for cheeses with a higher pH from the table above is the best approach, but it is important to remember that they are not truly alkaline.
