Making yogurt at home
4 cups of milk
2 tbsp of yogurt starter
Use any kind of milk that you prefer. The higher the fat content, the more custard-like and firm your yogurt will be. I use skim milk on a regular basis.
Pour milk into a glass container and heat in microwave for 6-7 minutes, or until the milk develops a thin skin on top. If, like me, you use skim milk or 2% milk, your milk will have more water content and it helps to allow it to cool and re-heat it a couple times to lose that extra moisture. With full-fat milk, there is next to no need to do this.
Discard any skin or film that may have developed by gently scooping it up with a clean spoon.
Allow milk to cool such that a drop feels just a tad bit hot on the back of your hand (not your palm) but pleasantly warm in your mouth. I’ve heard it bandied about that it should be 110-115F. I’ve never used a thermometer to measure it and I make yogurt at least 2-3 times a week, all year round.
If the milk is not as hot as required, heat it in the microwave for another minute or two.
In a separate bowl, whisk two tablespoons of your yogurt starter. This can be any commercial yogurt that has live cultures. I prefer Wallaby. You could ask a friendly Indian neighbor for some of their homemade yogurt or even an Indian restaurant. Niv says she uses kefir while Shilpa recommended Yogourmet.
Slowly add milk to the yogurt starter, a tablespoon at a time and mix. This brings the temperature of the yogurt up to that of the milk gently and does not shock the starter culture, if the milk is a little bit warmer than required.
Pour the starter + milk mixture into the glass container with warm milk and stir to mix. I stir 10 times in one direction and 10 times in the reverse direction. I have no explanation for this!
Place the glass container on a metal plate, like a stainless steel thali or flat lid, and place it in your oven as close to the oven light as possible. Cover it with another thali or lid. The metal conducts heat from the oven light bulb and helps maintain a warm temperature, conducive for the yogurt to set. It eliminates the need for wrapping the container in towels to keep it warm.
Turn on your oven light and leave this undisturbed for at least 6-8 hours. This is usually the last thing I do before I shut down my kitchen for the night.
By next morning, or 6-8 hours later, the milk should have fermented and become custard-like, possibly with a thin layer of whey floating on top. It may have a slight sour smell. That’s what you want.
If your glass container has a lid, put it on and place the container in the refrigerator to chill for at least 3-4 hours.
Homemade yogurt lasts in the refrigerator for upto two weeks. It is usually more tart than commercially-prepared yogurt. The longer it sits out, before refrigeration, the more tart it becomes.
Always set aside 2-3 tablespoons of homemade yogurt to use as starter culture for your next batch. The rule in my home is that my family can never ever finish the yogurt unless I have specifically told them they can do so. They’ve also learned to ask if they can finish it.
Homemade yogurt has more whey. We mix it right back into the yogurt or pour it over rice and dal.
Until your homemade yogurt is potent, you will need about 2 tablespoons of yogurt to use as starter culture. After a couple of weeks or rounds of making yogurt, try reducing it to 1.5 tablespoons. For 4 cups of milk, I don’t go below 1 tablespoon.