You can make oat yogurt from either raw or cooked oats. You can use oat groats, rolled oats or steel-cut oats, or oat flour, whatever you’ve got. For the best flavor and nutrition, start with unprocessed raw whole oat groats. Groats is just another word for grains. It’s traditional to call buckwheat grains and oat grains, groats. Start with either unprocessed oats or milled oats, then let them ferment.
Friendly micro-organisms called Lactobacilli are everywhere. They’re related to the friendly bacteria that naturally live in your colon, and the ones in dairy yogurt. They like starch and fiber, and will reproduce happily if you give them a culture medium of water, starch and fiber. The kind of bacteria that grow is dependent on what food you provide them. Micro-organisms produce substances that help them and suppress their rivals, so the good lactobacilli produce acids that suppress fungi, yeasts, bad bacteria, etc.
Oats are creamy, because of their high fat content, so the result comes out resembling dairy yogurt or sour cream. If you make it thicker, and let it get more sour, it will be more like sour cream.
To make oat yogurt more quickly next time, save some to use as starter. If you’re going traveling, keep the starter in a ceramic bowl with a plate on top, or a jar with a cloth on top held on by a rubber band. Put it in the refrigerator until you’re ready to use it. Cold slows down the growth of the lactobacilli, warmth speeds it up.
The sour flavor comes from lactic acid, just like in dairy yogurt, sauerkraut, kim chi, kefir, sourdough bread, etc. Beneficial bacteria produce acids that suppress yeasts, including candida. Eating fermented foods helps promote the growth of the good bacteria that live in your colon, and reduces the growth of candida and other problematic organisms.
You could ferment any grain, just as people make sourdough from wheat, rye, etc. For pleasant recipes, oats are nice, since the result resembles yogurt. For more anti-candida activity, other grains with more carbohydrate and less fat would be good, since the healthy lactobacilli live on starch and fiber.
Some people have heard that all oats you buy are cooked. Only the rolled oats are pre-cooked. Whole unmilled oat groats are raw, and alive. Those are the ones that look similar to grains of brown rice. Steel-cut oats are raw, but they are not alive and fresh.
If you let it ferment a long time, it gets more sour. That means there are more of the beneficial bacteria, and the beneficial acids. If it’s more sour than you like, just mix it with some un-fermented oats and some water, until you get the taste you want.
The microorganisms in the oat yogurt need food. If you let the oat yogurt continue to ferment without adding any oat flour, eventually the yogurt microorganisms will consume all the carbohydrate in the culture, and then they may starve and die. Then the culture may be taken over by other microbes, and go bad, it won’t be healthy yogurt anymore. You can tell if that happens because it stops being sour, and smells bad.
If you need to go out of town for a while, put the kefir grain(s) in a fresh mixture of oat flour and water. Put the jar into the refrigerator. Don’t screw a lid on the jar, cover it with a cloth held on by a rubber band.
Oat Yogurt from Whole Oat Groats
Put dry whole oat groats through a grain mill or food processor. Either grind them into flour, or roll them into flakes, depending on the capabilities of your machine. Or put the oats in a blender, and grind them to oat flour. Or use rolled oats or steel-cut oats from the bulk bins at a store.
Put the oat groats in a ceramic or glass bowl, or a glass jar. Add some water, enough to get them moist, with a little extra water covering them. After a few hours, or overnight, put the soaked oats and the soaking water in a blender or food processor or mortar and pestle. Blend until smooth. Pour back into bowl
Let the Oats Ferment
Use a ceramic bowl, since healthy fermentation produces acids that could interact with a metal container. You can cover the bowl with a plate or a cloth to keep out dust, and to keep the oats from drying. If you use a plate, it doesn’t need to be a tight fit, in fact it’s better to let some air in, and to let carbon dioxide out. Leave the oats in a warm sunny place, on your kitchen counter or windowsill. If you have a gas stove with a pilot light, you can leave them on top of that.
Stir them once in a while. If they have absorbed all the water, add a little. There should be a little water on top, or around the edges. After a few days, taste them to see if they’re sour yet. Then taste them once a day. When they are as sour as you want, eitheru use the yogurt, or put it into the refrigerator if you don’t want them to get more sour.