Updated: May 18, 2020
If you have an instant pot, it’s really easy to make yogurt at home. I haven’t had to buy yogurt in over a year since I started making it myself. This recipe is fun because it's customizable and science based! You don't need to know or understand the science to make your own yogurt, but keep reading after the recipe if you're curious!
Homemade yogurt typically has higher levels of probiotics and you can control all of the ingredients that go into it such as amount of sugar, type of sugar, artificial sweeteners, and inclusions. You also have control over the level of tanginess and the thickness of the yogurt based on incubation time and amount of whey drained off.
- 1/2 gallon to 1 gallon
- 2-3 Tablespoons plain yogurt with live active cultures
You can use anything from fat free to whole milk. I like to use whole milk because it provides a richer flavor and texture. Whichever you choose to use, the recipe is the same. You can also choose to use conventional or organic. For a starter culture, you will need a single serving of plain yogurt with live active cultures. Make sure that the label states that there are live active cultures or that it lists a between 4 and 6 bacteria strains that are present like in the above photo. After you purchase this first starter culture, you’ll never need to buy yogurt again. You can just save a few tablespoons each time you make yogurt and use that as the starter culture for the next batch.
ANYTHING you want to add to your yogurt
Leave the starter culture on the counter so that it comes down to room temperature.
Pour the milk into the instant pot and put the lid on. This process doesn’t require steam build up so it doesn’t matter if the steam trap is opened or closed.
Click the yogurt button and then click adjust until it reads boil. When the boil stage is finished, the instant pot will beep. Measure the temperature. It needs to be at or above 180 F. If it is not then repeat the boil process until it reaches the correct temperature.
Once it is 180 F, it will need to cool back down to 110 F or lower. You can just let it sit and cool down on the counter, but that usually takes quite a long time and a film of the milk will form on top, making it harder for heat to escape. I prefer to remove the metal pot and cool it in a cold water bath. To do that, fill the sink with cold water and put the pot in it making sure that no water gets into the milk. You can also put ice in the water to cool it even quicker. Take a clean mixing utensil and stir the milk until it comes down to temperature. It usually cools in less than 5 minutes with this method. The more rapidly you cool it, the less clumpy the yogurt will be.
Once the milk is down to 110 F or below, take ½ a cup of the milk and mix it with the starter culture. Then mix that into the full batch of milk. If you used a water bath to cool down the yogurt, wipe the metal pot off and then put it back into the machine. Put the lid back on and click the yogurt button until it says 8:00. For less tangy yogurt, leave it at 8:00, for tangier yogurt you can increase it to 10:00. This number is in hours, so that’s how long it will incubate.
When the incubation is done, you’ll have yogurt! If you prefer Greek style yogurt then put it in the mesh bag and hang it above a bowl to drain the whey. The longer you let it drain, the thicker it will be. Save the whey to put in smoothies or dressings or you can discard it.
Eat the yogurt as is or add in additional ingredients to your liking.
Here's a more visual representation. Add milk, boil to 180 F, cool to 110 F, incubate 8-10 hours, drain whey, eat.
Why does the milk need to be heated up so high before fermentation?
The biggest reason to heat milk before fermenting (incubating) is that it improves the texture of the yogurt. The protein composition of cow's milk is about 3.3% total protein. Of that, 82% is casein and 18% is whey. During fermentation the bacteria consume lactose (sugar in milk) and produce lactic acid. Lactic acid denatures (unravels) and coagulates the casein, trapping most of the fat. Lactic acid does not denature whey protein and if they are not denatured, they will not coagulate to add to the structure of the yogurt.
This is where heat comes in. Whey proteins are not stable at high heat, so heating milk to 180 F or more will denature it. Once it is denatured, it can coagulate along with the casein during fementation and add to the yogurt structure. Skipping this step will make a thinner and more fragile yogurt.
Why does the milk need to be cooled all the way back down before fermentation?
If you do not cool down the yogurt before adding the starter culture, the live active bacterias will be killed and fermentation will not occur.
Why does incubating for 10 hours instead of 8 make the yogurt tangier?
The pH of yogurt ranges from 4-4.6 with an average of 4.4. The longer the yogurt incubates, the more acid is produced by the bacteria, and the lower the pH gets. Lower pH (higher acidic) yogurts are tangier. The longer time also allows more of the lactose to be digested by the bacteria, which is why people who are lactose intolerant can often tolerate yogurt.
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Mix a packet of ranch dressing seasoning into yogurt and use as veggie dip or salad dressing.
Let me know if there is anything else you want to know about making your own yogurt in the comments or on Instagram @PlannedPlate.