I started experimenting with home made yogurt about a year ago after hearing my parents rave about how easy it is to make it and how much more "yogurt" flavor you can get compared to store-bought ones. Easy for them to say because their rice cooker has a fermentation setting for yeasted bread dough. All they have to do is to put the container in the rice cooker and let it go overnight, and come morning, voila! Freshly made yogurt fruit bowls for breakfast. It is so easy that they make single portions everyday.
My rice cooker doesn't have the fermentation setting, so I tried using the steam oven. It worked but seemed such a waste to have the oven on for ten hours for just a little tub of yogurt. I also tried the slowcooker (temp is too high) and the thermos (temp is too low) until I finally figured out a fool-proof and energy efficient way of making yogurt.
I don't like my yogurt too runny, so it took me some trials and errors to find the brand of milk that gave me the texture I wanted: like the soft set tofu or almond tofu dessert you find in Chinese restaurants.
500ml Marigold HL milk (it is low fat but not skim)
1 tsp milk powder
1 tbsp plain yogurt with active culture
1. Stir together milk powder and milk in a small saucepan, heat up to 90C
2. Preheat rice cooker (mine has a "warm" setting) with water in the container that you normally put rice in (try a few times to get the right amount of water so your container doesn't float in the water)
3. Wait for milk to cool to 45C (takes about 30 min in Singapore's weather)
4. Stir together milk with 1 tbsp of yogurt in a clean container with a loose fitting lid
5. Turn OFF rice cooker (This is important, because otherwise it's too hot) and place the container with lid on into the water bath.
6. Close the rice cooker lid and let it sit for 10 hours. Do not open the lid until time is up.
The yogurt I use as a starter is this brand, but any plain yogurt that contains active lactobacilus such as acidophilus is fine. You will only need to buy it once, for your first batch. Thereafter you can just reserve 1 tbsp from each batch as the starter for your next batch.
The yogurt that comes out looks like this, and will release whey as it sits in the fridge. The taste is pretty sour compared to the ones you buy from stores.
If I'm using it for smoothies or eating with fruits I use it as it is. If I'm cooking and the recipe calls for Greek yogurt, I drain it for a few hours over a sieve in the fridge so it becomes thicker. You can add fruit puree or honey to it if you get bored with plain yogurt. I use the whey in my smoothies as a thinner so nothing goes to waste.
The hardest part for me was finding the right appliance that can provide the right temperature for the yogurt culture. It took a while and I got discouraged a few times, but I'm so glad I didn't give up. I don't know why, but there's definitely something empowering about having yogurt on demand right in your own kitchen ;o)