A Step-By-Step Guide to Inoculating Milk for Cheesemaking

The first step to making cheese is inoculating milk with culture, then setting the curd with rennet. Here’s a step-by-step breakdown of this process.

This post on inoculating milk for cheesemaking is part of a series of posts on cheesemaking. Check out How to make homemade cheese for a complete list of topics.

1. Heat the milk

Milk needs to be warmed up to the right temperature to culture the bacteria.

The milk can be heated on the stove, whisking frequently to make sure the milk heats evenly (my usual method.) The milk can also be heated in a microwave or with a double-boiler.

Whichever way you choose, don’t overheat the milk, because it will cause the protein to denature and you won’t be able to make cheese.

Here’s a general temperature guide for heating milk. Regardless, it is always best to follow your recipe.

• Goat milk is heated to 88F (31 C) or less, regardless of culture.
• Mesophilic cultures usually culture at 90 F (32 C)
• Thermophilic cultures usually culture 91.5F (33C).

2. Add bacterial culture

Once the milk is at the right temperature, stir in the bacterial culture and maintain the temperature. As long as the milk is at the right temperature, the lactic bacteria will break down the lactose and acidify the milk. This is important because each type of cheese has its own level of acidification.

Cheese producers test the acidity levels, however, that sort of precision isn’t necessary for homemade cheese. To achieve the right level of acidification:

• Start with a recipe
• Use the right type of culture
• Maintain the correct temperature for the right amount of time

I maintain the temperature of my milk using my Brød & Taylor Bread Proofer & Yogurt Maker. Milk can also be kept warm by nesting the pot in a basin of warm water and maintaining the temperature by adding boiling water to the basin. See cheesemaking equipment for more information.

3. Set the curd and condition the milk

Calcium Chloride

If you are using goat milk, sheep milk, or pasteurized cow milk, then you need to condition the milk with calcium chloride.

1. For each gallon of milk, mix 1/4 tsp of food-grade liquid calcium chloride into 1/4 cup of chlorine-free water.
2. Thoroughly stir the calcium chloride into the milk for about 5 minutes before adding the rennet.

Rennet

Here’s how to add rennet to set the curd:

1. Mix the rennet (either liquid rennet or a rennet tablet) in a 1/4 cup of chlorine-free water (or as directed on the package).
2. When the rennet is fully mixed into the water, stir the rennet water into the milk. Stir thoroughly for about 5 minutes, mixing the milk up from the bottom of the pot so that the rennet is well-distributed.
3. Continue to maintain the temperature of the milk, without stirring, so the rennet can set the curd. This usually takes about 30 minutes.

For more information on testing the curd and preparing it for making cheese see preparing cheese curd.