1 Packet Yogurt Starter (ours was 5 grams) or 1 tablespoon prepared yogurt with live cultures
In an Instant Pot with a yogurt function, remove the seal from the lid. Clean the lid and the inner pot with hot soapy water, or place in the dishwasher, and dry thoroughly. Set aside. (see note)
Heat milk in clean medium pot over medium heat until it has started to steam and bubble around the edges, to 180ºF (we like to use our Thermapen for this).
Place the hot milk in the Instant Pot inner liner, and let cool until it reaches 105ºF - 110ºF, about 40 minutes.
Once it has cooled enough, in a small bowl add the live culture together with about ¼ cup of the milk and whisk until it is fully combined. Add it back to the inner pot, whisk until combined.
Press the Yogurt function on the Instant Pot until it displays a timer. Set for 8-16 hours, depending on how tangy you want your yogurt and close the lid (without the inner seal). It does not matter whether you press sealing or not.
Once finished, smell the yogurt. It should be pleasantly tangy.
To make greek yogurt: Line a fine mesh strainer with either a clean cotton kitchen towel, a coffee filter and two layers of cheesecloth. Pour the finished yogurt inside and let it drain for 2-6 hours, or until desired consistency.
Yogurt will keep in the refrigerator for 5-7 days.
Read the entire article on How to Make Coconut Milk in the Instant Pot.
You want to make sure the Instant Pot is clean for two reasons: the first is because you are fermenting food and you want to make sure there is no bad bacteria on your Instant Pot. The best way to do this is to put all of your equipment through the dishwasher right before use, or wash with hot and soap water. The second is because if there is any smell leftover on your lid or inner pot, which is known to happen in an Instant Pot, it will likely transfer to the yogurt. So clean it really well.
You heat the milk up for two reasons: the first is to kill of any bad bacteria, the second is because heating it up changes the protein structure of the milk and allows for the resulting yogurt to thicken up.
We are heating up the milk in a pot on the stove because we do not like the cooked milk solids that occurs when it is heated in the Instant Pot because it results in chunky yogurt. If you wish to use the function on the Instant Pot that brings the milk to the proper temperature you can do that.
You want your cooled milk temperature to be accurate before adding your culture because if it’s too hot, it could kill the live culture but if it is too cold it might disturb the fermentation. If you wish to speed up the process of the milk cooling down you can place the pot in a ice bath. Just make sure to watch the temperature as it will cool quickly, around 10-15 minutes depending on how cold the ice bath is. If you cool off the milk in ice in the IP inner pot make sure to dry it off thoroughly before using.
There may be a thin skin that has formed on the milk after it has cooled. This is normal, but we remove it to make for a smoother yogurt.
The longer you ferment the yogurt, the tangier it will be as the bacteria consumes all of the sugar and the more probiotic bacteria will grow. We tried the yogurt at 8 hours, which was not very tangy at all, to 16 hours which was a bit too tangy for us. We preferred the yogurt on the higher end of fermentation around 12 hours. However depending on the type of culture you are using it may give a different length of time, so be sure to check the instructions on how long to ferment the yogurt.
Depending on what yogurt starter you used will change how long you need to strain the yogurt to get thick greek style. If it goes too long and is too thick for your liking you can always add back in some of the whey.
Don't throw away the whey! It's full of protein. You can use it in smoothies or as cooking liquid in pasta, rice, potatoes, etc.
If at any point in the process your yogurt starts to smell bad, taste bad, or has any gray or pink liquid something has gone wrong and you will want to throw it out. Yogurt should be pleasantly tangy, but not taste “bad”.