One of the benefits of milking my neighbor’s goats was access to fresh, raw goat milk but, somewhere along the way, I got a little nervous about consuming raw milk and learned how to pasteurize milk at home. Once I graduated from “milking trainee” to official goat-sitter, I was worried that maybe I wouldn’t be able to tell if a goat was sick (some of them acted weird with me, just for something to do I guess) and then I started to question if I was being sanitary enough with milking. So I started to pasteurize the milk and it turned out to be pretty easy. The odds of my regular readers having raw milk to pasteurize is probably slim, but I figured I’d share this anyway – in case it does help, or even just interest, you! Keep reading for a little info on raw milk and details on how to pasteurize milk at home, if you’re curious.
What is Raw Milk?
I still see a lot of confusion online about raw milk and some folks seem to think “raw” milk is just milk “fresh” from a cow or goat or sheep – and some folks consider the milk they got on the farm and boiled “back in the day” to be “raw”. NO! Boiling milk is essentially a kind of pasteurization. Raw milk is completely UNPASTEURIZED milk. Raw milk is straight from the animal and has NOT been heated in anyway, thus it may contain harmful bacteria. I must emphasize that people can get very sick from drinking raw milk.
What is Pasteurization?
Pasteurization is a process that heats milk, at a certain temperature and for a certain time, in order to kill any harmful bacteria (like salmonella, E. coli, Listeria, etc.) lurking in the milk. Developed by Louis Pasteur, in 1864, pasteurization (if done correctly) eliminates the risk of food poisoning by killing harmful microorganisms. Pasteurization also extends the shelf life of milk. You can buy milk pasteurization machines (surprisingly inexpensively), but you can also pasteurize milk at home in a double boiler.
How Does Raw Milk Get Contaminated?
There are many ways bacteria can get into and contaminate raw milk. The animals can contaminate milk during the milking process. For example, if their feces or even bacteria from their skin gets into the milk, it can become contaminated. Before milking, we brushed the goats and washed the udders to minimize this risk. But bacteria can also be present already in the milk from sick animals.
she’s just sleeping – she was too cute not to include
Even if the animals are both healthy and clean, humans can contaminate the milk during the milking process, especially if the equipment isn’t sterile or their clothes/boots are contaminated. We strained the milk, thoroughly washed the milking equipment, and washed our hands. But ultimately, there are many chances for milk to get contaminated along the way…
Why Do People Rally Around Raw Milk?
Proponents of raw milk argue that there are many (good) bacteria, probiotics, enzymes, etc., that are reduced/altered/destroyed during the pasteurization process. The governments of countries that ban the sale of raw milk typically deny this, claiming the nutritional value of pasteurized milk is the same as unpasteurized milk. Some peer reviewed studies apparently do point to health benefits of raw (although many others find the opposite) and so I, if I’m being really honest, found myself curious about raw milk. From my research, a big part of the problem seems to be that to safely sell raw milk, farms really need to be stringent with cleanliness and handling – even routinely testing animals for certain diseases. It’s a LOT more work, undoubtedly more expensive, and not risk-free. Pasteurizing milk, on the other hand, means that it really doesn’t matter if there is feces around or if the milking environment isn’t perfectly clean – the milk get sterilized anyway. Although the sale of raw milk is banned in Canada, Australia, and parts of the US, it is sold in parts of Europe – with the caveat that it comes with risks. Personally, I decided not to take the risk.
Supplies for Pasteurizing Milk:
- Double Boiler
- Thermometer
- Sink with Cold Water
- Ice Cubes or Freezer Packs (LOTS)
- Glass Canning Jars
- Leak Proof Lids
- Funnel
CAUTION: Make sure your supplies and work area are clean and sterilized! Also be sure to wash your hands and keep pets away.
As a side note: I have recently discovered these plastic, leak proof lids for canning jars and they are AWESOME! I love them for storing dried goods or liquids – anything that doesn’t need to be canned, because I hate how rusty those metal canning lids get. This is a neat, clean, and dishwasher-safe option for storing food in canning jars.
How to Pasteurize Milk:
- Disinfect clean canning jars (by boiling for 10 minutes or placing in an oven heated to 100° C (212° F) for 20 minutes).
- Fill the bottom of a double boiler half way to the top with water and place on a stove element.
- Pour the raw milk into the top part of the double boiler.
- Turn the heat to high and bring the water to a boil.
- Stir the milk constantly, to keep it from scalding and to make sure the milk is heated evenly throughout.
- Check the temperature of the milk often with a clean, reliable thermometer.
- Place the thermometer two-thirds of the way into the milk to get an accurate reading (do not place on bottom of pot).
- Raise the temperature of the milk to 63° C (145° F) for at least 30 minutes OR to 72°C (162°F) for at least 15 seconds.
- If the temperature drops below your goal temp (see above), you MUST get the temperature back up and re-start timing.
- Fill a sink or large bowl with cold water and then add ice and/or freezer packs (making sure not to fill sink beyond depth of pot).
- Place the top pot from the double boiler in the sink to rapidly cool it (I set a cutting board down in my sink, first).
- Keep stirring the milk, this time to help it cool faster.***
- Quickly cool the milk so it reaches 20°C (68°F) or cooler.
- Pour the cooled milk into the sterilized glass jars.
- Refrigerate immediately – in a fridge that is 4°C (40°F) or colder.
***A key part of pasteurization is not only heating the milk to a certain temp for a certain time, but also QUICKLY cooling the milk. That’s why an ice bath – or even putting the pot into a big vat of ice – is important, as is quickly refrigerating the milk once cooled. I couldn’t make/store enough ice quickly enough, so I grabbed some freezer packs to supplement and that worked too!
How to Pasteurize Milk in a Double Boiler on the Stove – Detailed Instructions:
First, disinfect some clean canning jars. You can do so by boiling for 10 minutes or placing in an oven heated to 100° C (212° F) for 20 minutes, much like you would for canning. Choosing canning jars is safest for storing milk because other glass jars may not be able to withstand the high heat of the jar sterilization process. Fill the bottom of a double boiler half way to the top with water and place on a stove element. You can fill it more, if that works better, but you don’t want it to be bubbling over. Pour the raw milk into the top part of the double boiler. Turn the heat to high and bring the water underneath to a boil.
Stir the milk constantly, to keep it from scalding and to make sure the milk is heated evenly throughout. If you don’t stir the milk, it can scald a little to the bottom of the pot but, more importantly, when you measure the temperature you might not get an accurate reading because some parts of the milk maybe hotter or colder. It’s annoying, but stir CONSTANTLY throughout the pasteurization process for best results.
Check the temperature of the milk often with a clean, reliable thermometer. Place the thermometer two-thirds of the way into the milk to get an accurate reading (do not place on bottom of pot). If you measure the milk at the bottom, closest to the boiling water below, you won’t get an accurate reading. Raise the temperature of the milk to 63° C (145° F) for at least 30 minutes OR to 72°C (162°F) for at least 15 seconds. CAUTION: if the temperature drops below the goal temperature for either method above, you MUST get the temperature back up and re-start timing.
Once the milk has been pasteurized, fill a sink or large bowl with just ice or, if you don’t have enough, with cold water and then add ice and/or freezer packs (making sure not to fill sink beyond depth of pot). It’s better to have less water than needed – you can always add more water or ice to top it up. You want the pot fully in the water, but do not allow the water to enter the pot of milk and contaminate the milk. Place the top pot from the double boiler in the sink to rapidly cool it (I set a small cutting board down in my sink, first). Keep stirring the milk, this time to help it cool faster. Quickly cool the milk so it reaches 20°C (68°F) or cooler.
Pour the cooled milk into the sterilized glass jars. Refrigerate immediately at 4°C (40°F) or colder. Write the date of pasteurization on the jars (FYI: Sharpie permanent marker comes off glass with gentle scrubbing, or a run through the dishwasher, so it’s a convenient way to label glass jars).
How Long Will Home Pasteurized Milk Keep?
Pasteurized milk (pasteurized immediately or very soon after milking and kept in the refrigerator), should keep for up to two weeks.
I hope you found this post on how to pasteurize raw milk interesting! And, although sometimes I question the health benefits of raw milk (and waffled a bit with my own consumption), I hope I made clear the healthy and safety risks associated with drinking raw milk.
I no longer milk my neighbors goats due to a hand injury and I’m honestly kind of missing those silly little goats. They were a HANDFUL, and it was so much more work than anticipated, but I did also enjoy access to such lovely, fresh milk.
P.S. Don’t Forget to Pin for Later!
