Growing up, my dad used to make the worst yogurt on this planet. It was yellow and watery and I would have none of it as a kid. Most recently, as a pandemic hobby, he got back into making yogurt. At first I was very skeptical, I had not completely recovered from the trauma of drinking what he deemed as "great yogurt" when I was a kid. But now, I have to admit, it seems he has mastered the recipe and now I want to share with the world how to make homemade yogurt!
Shameless plug: my dad is Doctor of Chinese Traditional Medicine from Vancouver, British Columbia so if you need treatment check out his website!
It is very important that the equipment and glass jars are sterilized and dried after. This is to ensure that there will be no other competing bacteria in the yogurt during the incubation process. An easy way to sterilize the equipment is the heat up or pour boiling water onto it. The glass jars can be pre-sterilized in a similar manner or can be done later as described in section 4 where we set up the insulating incubator.
1. Heat Up the Milk
The first step is to heat the milk up. This is to kill any competing bacteria in the milk. It also evaporates the water content in the milk and denatures the whey proteins to help thicken the final texture of the yogurt.
Place the wooden chopsticks in the saucepan to suspend the mixing bowl as seen in the image below. Do not use anything metal to suspend the bowl. This is so the heat transfer is distributed evenly across the entire bowl instead of concentrated at the bottom. This helps reduce the milk from curdling at the bottom.
Pour the milk into the mixing bowl and put it on top of the wooden chopsticks. Then pour around an inch of water into the saucepan or enough water so it does not all evaporate when heated to heat the milk. Note, in the picture below there is around 2.8L of milk.
Put the saucepan on the stove and set the temperature to the highest setting. Cover with a lid and heat the milk up until the milk is over 90C (195F).
2. Cool Down the Milk
Take the saucepan off the stove and with your whisk, scrape the insides of the mixing bowl to break down some of the milk curdling/clumping.
Remove the mixing bowl from the saucepan and let it cool until the temperature reaches 40C (105F). Be sure to stir it every once in a while to remove the skin that builds up as it cools.
In the picture below, we opened the window to help cool the milk but for faster cooling put the mixing bowl in an ice bath and stir occassionally.
3. Mixing in the Yogurt
Slowly and thoroughly mix a few cups of the milk into the yogurt. This is to make sure the yogurt is less viscous so it can be mixed back into the milk more easily.
Slowly and thoroughly mix the thinned yogurt and milk combination into the mixing bowl with milk.
4. Setting up the insulated incubator
One of the most important steps is incubating the yogurt at a warm temperature. To prepare for this, heat up a few cups water to around 45C-50C (113F-122F) inside a pot (the pot we use is the one that comes with the thermal cooker).In the picture below, we also put the yogurt containers inside and instead, heat the water with the pot lid closed until it steams. This is because we also sterilize the yogurt containers simulataneously (note, if you do this, make sure to keep the lids closed as you do not want water inside the containers).
Take the containers out and place the pot inside the insulator (in our case the thermal cooker). Add cold water until the internal temperatures reaches 45C-50C.Alternatively, one can wrap the pot with insulating clothes and put it in a microwave, though results may vary depending on well everything is insulated.
5. Incubate your yogurt babies
Pour the mixure into each of your yogurt containers.
Place the containers into your insulating incubator, close it and you can even wrap it with more clothes for good measure.
Let your yogurt babies grow for 12 hours.
6. Cool down and enjoy!
Put your yogurt containers into the fridge for around 6 hours and enjoy!