Pasteurizing Milk at Home
I am a dairy farmer and I like pasteurizing milk at home for us to drink. Why you may ask? Well, without getting into the whole raw vs. pasteurized milk debate, it is our family choice and we feel safe knowing any potentially harmful bacteria in our milk has been removed. The milk is convenient for us to get out of our milk tank and I wanted to share my process and the things I’ve learned in order to help someone else out who wants to do this process at home. Raw milk may or may not be legal to sell or purchase in your state. It is legal in Kansas, but the cooperative that we sell our milk to does not allow us to sell raw milk to other sources as we are contracted to sell all our milk to them.
Don’t have access to raw milk and you are buying from the store? Check out my other posts to determine how to be sure you are buying local milk and what the difference is in different white milks!
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Pros & Cons of Pasteurizing Milk at Home
Since we do have access to raw milk, I like pasteurizing it at home because with the price of milk at the store right now, anything to make that grocery bill a little lower is a life saver! Especially as we go through 3 to 4 gallons of milk a week! This process also saves us a lot of plastic milk jugs that get thrown away more often than they are recycled. The really only downside is that it takes time, but usually I do this processes while I’m cooking supper and it isn’t a lot of extra work. It has taken some time to get the process down correctly so that the milk tastes like the stuff purchased from the store. If I over cook it, or cool it too slowly, it can have an off flavor.
Collecting the Materials Needed
Most of the materials needed to pasteurize milk, I already had around the house. But ultimately, they aren’t too expensive. A lot cheaper than a 2 gallon home pasteurizer for $400!
Items Needed:
Wire Hanger
2 Half Gallon Glass Milk Bottles
Oven Mitts (not pictured)
Plastic Kitchen Funnel (not pictured)
Step 1: Warming Milk to 165º
The first step is to warm the milk to 165º for 15 seconds. To do this, I put the stock pot on the stove and create a double boiler. I put a hanger through the handles of the stock pot to create a cradle to suspend the insert of the ice cream maker from. Fill the insert with milk and put water in the stock pot to reach about 3/4 the way up the insert. The purpose of the water is to heat the milk without scalding or scorching it. This also makes it so the milk does not have to be stirred constantly, I just stir every few minutes or so to keep a skin from forming on the top. If one starts forming, stir it in and it will blend back in with no issues. Turn the burner on high and begin heating.
I have never timed how long it takes to heat the milk to 165º, but it depends on how cold the milk and water are at the beginning of the process. I just periodically stir the milk and check the temperature. Once the milk gets to 165º, hold it there for 15 seconds. This is considered flash pasteurization and I found these instructions from Oregon State University.
If the milk gets a little warmer, like around 170º because I’m not paying close enough attention, it is just fine. The biggest issue is I don’t want it to get too hot as it will increase cooling time and it could give the milk a cooked flavor, especially if it reaches boiling.
Step 2: Cooling the Milk
Cooling the milk is the most important step for flavor preservation. The faster it is cooled, the fresher the flavor and I avoid that cooked taste. This is the part that took me the longest to figure out.
Once the milk has reached 165º for 15 seconds, I VERY CAREFULLY take the insert of milk out of the stock pot and put it in the ice cream maker tub. I wear oven mitts for this and DO NOT spill it on myself! Keep the tub close to the stock pot for this so the transition is not across the whole kitchen.
Put the stirring paddle and lid on the milk. Add ice to the ice cream maker. Ideally it should be all ice, but my ice maker does not make enough ice to fill my tub, so I have to add cold water so the ice water comes to an inch or two from the lid of the insert. Turn the ice cream maker on to stir the milk as it cools. The stirring is important so the milk does not form a skin on top as it cools.
Cool until all the ice is melted. I can get the milk down to around 60-65º with this process.
Once the ice is melted, transfer the milk to two half gallon glass milk bottles using a funnel. Cap bottles and place them into the freezer for 1 to 2 hours. I set a timer so I don’t forget to take them out! If there are a few chunks of ice in the milk it is okay, but I don’t want the milk to freeze solid and crack my glass bottles. When time is up, place into the fridge and enjoy a glass of milk whenever wanted!
Why Glass Bottles?
When I started pasteurizing milk, I just returned the milk to the plastic gallon jugs from the store. I realized this was some of my flavor issue. The milk didn’t cool as quickly in the gallon because there wasn’t as big of a surface area to volume ratio. The half gallon glass milk bottles fixed this. Milk is also supposed to stay fresher longer and taste better in glass versus plastic, but we drink our milk so fast, it probably doesn’t matter! It does look cute in the fridge though! Another tip to keep milk fresher longer is to store it farther back in the fridge for a more consistent, colder temperature. Again though, we drink ours so fast, I typically keep it in the door for easier access.
If you have any questions for me about milk or pasteurizing milk at home, please leave me a comment below!
You said you pasteurize while cooking dinner, so do you milk in the morning and then filter & refrigerate until evening and pasteurize then? I’m trying to get the routine down with my work schedule. I milk the goats before going to my other job and don’t really have time to pasteurize until evening. Also, how cold should milk be before going into the fridge (Both in the morning and after pasteurization, I’ve read conflicting info on different sites). Thanks for this article, it’s terrific!
We milk twice a day, so I use milk from the afternoon milking usually. As we are a commercial dairy cow farm, I usually don’t do the evening milking and can just grab some milk on my way home. So, I like to pasteurize it before it is even cooled down. I would say that cooling milk as quickly as possible is your goal both before or after pasteurization. There are times I have put it straight into the fridge after milking, which isn’t ideal. I prefer to put it into the freezer for a few hours if I can’t pasteurize it right away. Cooling in an ice bath with stirring is usually the fastest way to cool milk. After pasteurization, I can usually get the milk down to about 55-60 degrees in the ice bath. If I switched out the ice at that point I could probably get it colder, but I have used up all my ice by then. I can’t say I have actually done the research to see what the temp should be before you put it in the fridge. I just go with the fastest method I have to cool it down.
Do you separate the milk and cream before you pasteurize? Do you ever make any butter or other dairy products from the pasturized milk?
Sometimes I do separate the milk and cream before pasteurization if I want to make butter or ice cream. This is because the cream does not separate out as well after pasteurization. I am not sure why this is. If the heating and stirring thins the cream enough that it is partially homogenized? Again, just a conjecture. The only other dairy products I have made from the milk is yogurt.
How long last the milk in fridge before spoils ?
Our milk does not last long in the fridge because we drink it so fast! However, I wouldn’t go too much past a week, but it may last longer, I have just never needed it past then.