This fermented oatmeal milk recipe uses the magic of koji to break down the rolled oats into a creamy milk that is good for you too. Non-dairy milks are great for folks who are lactose intolerant. If you are choosing non-dairy milks for environmental reasons oat milk has one of the lightest footprints.
Making your own saves money, leaves you in charge of the ingredients, and helps keep single use packaging out of the system.
Homemade oat milk recipes rely on raw oats, which aren’t the best for our digestion. The advantage of using koji rice is that the enzymes in the koji rice breaks down the larger molecules of the oats. This leaves them more digestible with more of the nutrients available for our bodies to absorb, and tastier. The other advantage is that you won’t get slimy or goopey milk which can be a problem people experience with over soaking, over blending, or using warm water.
Let’s backtrack a moment for those of you asking, “What is koji?” let me define it. Koji is the Japanese name for Aspergillus Oryzae. Koji is a fungus, more specifically a filamentous fungus that grows on the surface of its host – often rice – releasing powerful enzymes to break down complex molecules. In food this means it will break down large starches into simple sugars, proteins into amino acids, and fats into fatty acids. These smaller parts are all more flavorful.
Using koji is harnessing enzyme magic!
Koji has been used for thousands of years, think of it as a domesticated mold. It gives us things like miso, sake, soy sauce and oh so much more. You can order rice koji online, or find at your favorite Asian market.
To read more about koji or learn how to make it yourself check out our book Miso, Tempeh, Natto and Other Tasty Ferments. We also have started teaching fermentation master classes online with our friends. Check out our ever growing list of fermentation classes.
Fermented Oat Milk Recipe
You will need a jar, a blender, a nutmilk or other fine mesh bag or cloth for straining, and a way to keep your jar warm for 6 – 8 hours, and the following ingredients.
1 cup (90 g) rolled oats
½ cup (100) rice koji (white or brown rice)
5 cups (1183 l) water, warmed to 135°F/ 57°C
Optional: pinch salt, ½ teaspoon (2 g) vanilla
The process is simple, as you can see in the above video.
You will pour the oats, rice koji and warmed water into a 2-quart jar. You will keep this at 135°F/57°C for the next 6 hours. (This can be done in a dehydrator, immersion circulator, instant pot, towels and a warm oven, towels and hot water bottles in a cooler…whatever you have.)
After 6 hours you will put in the fridge for at least 24 hours and up to 5 days. It will get creamier with a few extra days. It can get a little lactic (sour) tasting if you let it get to cook during the 6-hour heat time. If it’s gotten cool, process sooner.
When ready, blend it for about 30 to 45 seconds, or until oats are creamy. Strain through a nut milk bag and voilà (wa-lah) you have oat milk. This will keep in fridge about 5 days. It will separate and need shaking upon each use.
Use the strained-out solids in a sweet treat—part of the hydration of banana bread, or in oatmeal cookie dough.
