pH is a measure of acidity, which is very important in cheese making
Acidity can be expressed as pH. What exactly is acidity? Acidity can be described as the number of free protons (H+ atoms) floating around in the milk/cheese. This is a gross simplification, but good enough for our purposes. How do we increase the acidity? Cheesemakers (or their starter cultures) will add acid, which contain plenty of potential H+ atoms.
pH is just a number used to quantify how many free H+ atoms are present in cheese. Here’s the kicker, due to the huge amounts we’re dealing with (e.g. millions of protons), pH is a shorthand method of counting those protons. But since chemists like to make things difficult, the scale is inverted. Meaning, lower the pH – higher the acidity, and alternatively higher the pH – lower the acidity. pH is measured on a 14-point scale.
Common Cheese pHs
Below is a chart and scale that outlines common pH values for several cheeses. The numbers shown are usual values, and certain cheeses can definitely vary wildly in pH. Reader beware! Milk usually starts around pH 6.7 and from there varying amounts of acid are created to yield the final pH of the cheese. pH isn’t static; pH can change while a cheese is being made and ripened. Buffering can occur or an outside influenced can effect pH. Blue cheese, for example, starts its life at a very low pH (~4.6, high acidity) but then has its pH increased (~6.5, acidity lowered) due to the metabolism of the blue mold.
Drag the slider handles below to see where your favorite cheese falls!
|6.5-6.2||Limburger, Blue Cheese, Brie, Quesco Fresco, Bread Cheese|
|5.7-5.5||Gruyere, Swiss, Fresh Mozz|
|5.4-5.1||Gouda, Mozz, Parm, Colby, Cheddar|
|4.9-4.6||Cream Cheese, Feta,
pH, and furthermore acidity, have many effects on cheese. Some cheeses are coagulated via acid, as we’ve discussed before. Acid is a common flavor descriptor in many cheeses and varies wildly from cheese to cheese. pH level can have a dramatic effect on how well a cheese will melt, which we covered in a previous post. Acid development also serves as a safety measure. As more acid is developed (i.e. lower pH), pathogens don’t grow as quickly. There are many other potential impacts of pH on cheese, but, alas, those will have to wait until another day.
For More Information
- Dairy Pipeline - Cheese pH—What’s behind the rise and fall?
- Approximate pH of Foods and Food Products