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How to Freeze Dry Milk

Learn how to freeze dry milk in this step-by-step guide.
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Prep Time:5 minutes
Cook Time:2 days
Additional time:6 hours
Total Time:2 days 5 minutes

Equipment

  • Freeze dryer
  • Trays with silicone mats (for easy milk removal)
  • Storage container (glass jar, mylar bag, etc.)

Ingredients

  • 1.5 gallons Milk of choice (or enough to fill your freeze dryer trays)

Instructions

  1. Step 1: Prepare Your Milk for Freeze Drying
    When preparing milk for freeze-drying, I always start by freezing it. It’s not necessary, but I learned my lesson the first time. I didn’t set the freeze setting long enough, and my milk exploded in the freezer. By freezing it first, you eliminate that possibility, plus it cuts down on the freeze-drying time. So, if you have extra freezer space, I highly recommend it. 
    Line your trays with silicone mats to make it easier to remove the milk after it’s done freeze-drying. Put each lined tray in the freezer one at a time before filling it with milk. Stack each tray on top of each other in a crisscross pattern, separated by another silicone mat so they don’t freeze together. 
    How much milk should you add per tray? In my case, I add 5 cups of milk (40 oz.) per tray. However, the specific amount you’ll need to add will depend on the size of your freeze-dryer trays. (I bought extra 9.5″x12″ trays that hold a little more than the ones that came with my freeze-dryer.)
    Measure the milk the first few times until you know how much your trays can handle without overfilling. Leave a little room on top for expansion. Let the milk freeze for at least 24 hours. 
  2. Step 2: The Freeze Drying Process
    Once your milk is frozen solid, transfer the trays to your freeze dryer. Now comes the part where you set everything up. 
    Set the rack temperature between 110 and 115 ℉ for raw milk or between 120 and 130 ℉ for pasteurized milk.
    Set the drying time to at least 24 hours. Check to see if it's completely dry after 24 hours; Depending on how much milk is in each tray and the specific capabilities of your freeze dryer, you may need to freeze dry for an additional 6 hours (30 hours total). Make sure to adjust your settings according to your dryer’s model.
  3. Step 3: Storing Freeze-Dried Milk
    After freeze-drying, your milk will have transformed into a dry powder. At this stage, you can directly break up the freeze-dried milk and transfer it into your storage containers. 
    I transfer all the freeze-dried milk into a large bowl and mash it down with a whisk to get even smaller, finer particles so that I can fit more in my storage container. 
    Store your milk powder in an airtight container, such as a Mylar bag or glass quart jar.
    Quart jars are handy for smaller quantities you might use more regularly—they’re easy to access and excellent for keeping your milk powder ready. Mylar bags are great for long-term storage; that’s what I use.
    I add oxygen absorbers, then vacuum-seal the bags, label them, and store them in a dry place out of direct sunlight. 
  4. How to Redydrate Freeze Dried Milk
    Mix it with water by a 1:1 ratio by volume. Start with equal parts of freeze-dried milk and cold or warm water, adjusting as needed to achieve your desired consistency.

Notes

  • Freeze Your Milk First: It might seem like an extra step, but freezing your milk before placing it in the freeze dryer can significantly reduce the drying time. More importantly, it helps avoid the messy outcome of milk potentially exploding in the freeze dryer if the freeze cycle isn’t set long enough. Trust me, it’s a step you don’t want to skip!
  • Line Your Trays with Silicone Mats: They prevent the milk from sticking, making it much easier to remove once it’s freeze-dried. 
  • Leave Room for Expansion: When pouring milk into your trays, leave a little space to expand as it freezes. This helps prevent overflow and ensures even freezing.
  • Check for Complete Dryness: Before removing the milk from the freeze dryer, ensure it’s completely dry. Any moisture left can compromise the storage quality and shorten the shelf life of the freeze-dried milk.
  • Powderize the Freeze-Dried Milk: Once your milk is freeze-dried, breaking it down into a fine powder can make it easier to rehydrate and allow you to fit more into your storage containers. I typically freeze-dry about 1.5 gallons each time and manage to fit it all into a 32-oz. Mylar bag by mashing the milk into a fine powder.
  • Add Oxygen Absorbers to Your Storage Containers: To extend the shelf life further, place oxygen absorbers in whatever storage containers you use. This helps keep the milk powder fresh by preventing oxidation, ensuring your milk stays good for years.