All you need to pasteurize milk at home is a stove, stainless steel pot, and a thermometer. You slowly warm the milk to 145F and hold the temperature there for 30 minutes. Once done, you’ll quickly cool the milk down to 40F (by putting the pot in a sink with ice water) and then store in the refrigerator.
Using a stovetop however, comes with a few things you’ll need to watch.
First, when warming your milk, you’ll want to stir it often to keep the heat dispersed throughout. If you let it sit too long without stirring, it can scorch (or scald). It can also scorch if you heat it too quickly. If you have a double-boiler, this is even better then a single pot and decreases the likelihood of scorching.
I put a dedicated thermo probe in the milk so that I know its temperature at all times. Once you’ve reached your target temp of 145F, you’ll need to watch the heat and keep stirring to keep the temperature up. This may entail increasing or decreasing the heat of your stove to keep the milk above 145F for the full 30 minutes.
Finally, when cooling, you’ll also want to stir in order to cool it down quickly. The longer it takes to cool, the better the opportunity for spoilage or bacterial contamination.
Enter sous vide
I decided to try pasteurization using my Anova immersion circulator. Since I use it regularly to make cheese, it made sense to try pasteurization with it as it almost eliminates the possibility of scorching. The longest part was getting the water bath up to 148F (I set the circulator to get the water bath about 3-4 degrees hotter than my target temperature of the milk). The next time I do it, I’ll get the circulator going ahead of time to get my water heading towards 148F. While scorching is not nearly as likely, stirring is still recommended just to disperse the heat evenly to get the milk up to the needed 145F. I still keep a dedicated thermo probe in the milk so that I know it’s at the proper temperature. Once the milk hit 145-146F, I was able to walk away from it and it maintained the steady temperature the entire time. The process was easy and I think I’ll move to use my sous vide circulator for my future pasteurization needs.
Your comments are always welcomed!