To begin making dahi, rinse a heavy bottom saucepan. Rinsing the pan keeps the milk from scorching and sticking to the bottom of the pan.
Pour the milk into the pan and heat it on medium heat until the milk comes to a boil. Note: Boiling the milk helps to kill any bacteria and improves the texture of the curd.
If you don't like cream on the curd, keep stirring occasionally to reduce the formation of cream on the milk.
Once the milk comes to a boil, reduce the heat to low and simmer for another 5-8 minutes for a thicker curd.
Take the pan off the heat and set it aside. Let it cool down until it feels lukewarm. The easiest way to check milk is to dip your finger into it; it should feel cozy, warm, and never hot.
Add the yogurt with active culture to the lukewarm milk. Whisk or stir well until the culture is blended well with the milk.
Transfer it to a steel container or glass bowl. You can also use an earthen pot to set the curd since it gives a sweet and earthy flavor.
Keep it in a warm place like an oven or instant pot for 6-10 hours, based on the weather.I have used Instant Pot with the yogurt function to ferment the curd. Place the container in the instant pot above a trivet and Close the lid on the Instant Pot.
Let the pressure valve be in the VENTING position. Set the pot to YOGURT mode.
Let the yogurt incubate undisturbed for 6 to 8 hours, depending on your desired tartness and thickness.
Once the yogurt is set, place the container in the refrigerator and let the curd chill for a few hours to set completely.Note: Ensure to reserve a small amount of the homemade yogurt to use as a starter culture for your next batch. This practice helps to maintain consistency in subsequent batches of yogurt preparation. Your homemade yogurt is now ready to be enjoyed!