Back before I began culturing frequently, I bought milk without much thought. I tried to get organic when it became available, sought out local dairies and looked for a good price. When I began to use dairy in culturing when I received milk kefir grains from a friend, I learned there was a lot more to milk! And more options have become available in the years since. Most people know the difference between organic and conventional milk. In the US, milk must undergo certification by a recognized agency to carry the organic label. The regulations cover feed, medication and how the milk is treated. For dairy milk, the type of pasteurization must be indicated on labels in the US. There are 4 types of pasteurization that are defined. Raw milk is milk straight from the dairy animal. It is generally not heated over 118°F and the sale is regulated and sometimes prohibited. Thermization or Low-Temp pasteurization occurs at 145°F and is not as common as the other methods. For cheesemaking, it is not recognized in the US as full pasteurization. It does make beautiful cheese for home cheesemaking though! It also works well with cultures. If you are using an heirloom culture, my opinion is that it does work best to establish the culture in regular pasteurized milk and then switch to this milk. The most common method is regular pasteurization, which occurs at 160°F. This is the milk we recommend starting most cultures with. It is widely available, does not cause bacterial competition with the cultures, and works very well! Ultra Pasteurization occurs at 280°. Ultra Pasteurization is becoming more and more common, especially with organic milk. It has the longest shelf life, allowing the milk to keep for several months in standard packaging or up to 9 months in special shelf-stable packaging. This provides considerable cost savings to dairy companies. However, Ultra-Pasteurized is a poor choice for culturing. I have had some batches work with a direct-set starter to make sour cream. Otherwise, it just doesn’t do anything really. Another process milk goes through is homogenization. The prevents the cream from rising to the surface of the milk. This can be really helpful in activating a new culture. The starter tends to rise with the cream and get trapped in it. However, once your starter is active, using non-homogenized milk is fantastic. Cream-top yogurt, made at home! But how do you know what milk to buy when you are standing at the dairy case? Fortunately, finding the right milk is easy to do. I visited my local naturally-minded store, New Seasons at Orenco Station. They kindly agreed to allow me to take some photos to help! Blog_Choosing Milk for Culturing_Sarah_1 See how it says “Pasteurized” right on the label? Often, it is as easy to find as this. Sometimes it can hide a bit. Here’s another example: Blog_Choosing Milk for Culturing_Sarah_2 Squint right there at the top, next to the Grade A. Pasteurized! This cream is also homogenized. Both the above milk and this cream will culture beautifully. If you are activating a culture, stick with the milk. Then culture the cream with your active starter. Blog_Choosing Milk for Culturing_Sarah_3 Here is a lactose “free” milk which is something we get asked about occasionally. See the lower right corner? It says Ultra-Pasteurized. So while it is organic, whole milk, it just isn’t a good choice for culturing. If you have questions about using Lactose-Free milk, be sure to ask our customer support team! Blog_Choosing Milk for Culturing_Sarah_4 And finally, here’s an example of non-homogenized milk. They usually proclaim “cream on top” because, well, YUM! But as I mentioned earlier, this really isn’t the best choice for starting your cultures. Once they are awake and culturing reliably, then feel free to make the switch. What if your only option for regular pasteurized milk is cream top? There is a way to make it work! One is to pour out a generous helping for yourself first, before shaking the carton. This will pour out most of the cream. Another method is to pour the milk into a jar or measuring cup. Allow the milk to sit at least overnight in the fridge. Scoop the cream off the top (as best you can) and then use the remaining skimmed milk for your culture. Now you are all set to start culturing! Check out our cultures for milk kefir, yogurt, buttermilk and cheese. And as always, if you have questions about ingredients for your cultures, contact our customer support team!