Calcium Chloride Role in Making Cheese

Calcium chloride can be used to condition pasterized, homogenized milk so that a heavier or more dense curd can be formed with longer protein chains. The manufacturing processes of pasteurization, heating and rapidly cooling the milk, and homogenization decreases the amount of calcium in the milk and can affect the clotting properties. Calcium chloride is used to re-balance the calcium content of milk.

Many of the questions we get from cheese makers involve issues related to weak curds: the whey is not clear and the curds are too soft. Very often, the problem is caused by insufficient calcium.

Food grade calcium chloride is nothing more than a natural mineral salt, used in pickles (pickling salt, such as Pickle Crisp), beer, tofu, bottled water, soda, etc.  The beauty of calcium chloride is that it adds calcium ions to the milk and slightly raises the amount of acidity during the cheese making process (more about this below). And, because it strengthens the protein molecules in the milk, it boosts the yield of our cheese by as much as 2-3%.

It’s all about the acidity of the milk.  When milk comes from the animal, it is usually at a certain level (although this itself may be lower than usual if the animal is in the late stage of it’s lactation cycle or if it’s fighting off an infection).  The goal of the cheese maker is to raise the acidity of the milk to the optimum point for coagulation.  We use several tools to achieve this- usually heat, acids (lemon juice or vinegar), bacteria (starter cultures)* and enzymes (rennet).  We use these tools in all kinds of different ways, combinations and speeds to achieve a wide variety of cheeses.

The goal is to separate the curds from the whey, but there is a complicated chemical process involved in this and a lot of it depends on the amount of calcium ions holding the protein molecules together. The amount of calcium ions has a lot to do with the acidity of the milk. If the acidity is too low, the milk does not have enough calcium ions to facilitate coagulation.

How to Use

We add it to milk at least 5 minutes before adding the rennet. Usually the amount is the same as the amount of (single strength) rennet we will be using. This is generally 1/8 – 1/4 teaspoon per gallon of milk (recommendations vary). We suggest that if you are using store-bought pasteurized and homogenized milk, you use up to 1/2 teaspoon per gallon (our FAQ section). (Note- no amount of calcium chloride will compensate for ultra-pasteurized milk.) Before you add it to your milk, dilute it in 1/8 – 1/4 cup of water (per gallon of milk used).

Please do not think that using more will be better - it will not. In fact, it will have a reverse effect and slow the coagulation of your curds.

An example of how to use it: If you have added the culture to your milk and you are letting it ripen for one hour, add the calcium chloride solution after that and let the milk set for 5 more minutes before you add your rennet.

Using in Brine Solutions

Calcium Chloride can also be used in your brine solutions to balance the calcium levels between brine and cheese, which can prevent your cheese ‘melting’ or going slimy when it is being preserved. This is a reasonably common issue and the addition of CaCI2 to the mix is usually a reliable solution as it establishes an even balance and stops the calcium from being leeched from the cheese into the brine, causing the cheese to soften and melt.

Calcium chloride should not be used to make mozzarella cheese because it causes a loss of elasticity of the curd (Ismail, 2008).