Basic How To: Yogurt/Curd/Dahi
Preparing yogurt, also referred to as ‘curd’ by Indians, or dahi in Urdu language, the wonder food, a natural antibiotic, at home is quite a simple task. Just like milk, yogurt is packed with good nutrients including protein, calcium, magnesium, potassium, zinc and B vitamins. Probiotic yogurts with active cultures helps reduce constipation and bloating, and boosts immune system function. Yogurt is one of the essential ingredients in Indian cuisine. Its sweet-sour flavor is used in marinating the meats, and to prepare gravies for curries, as a dessert, in face-packs or hair-packs etc.
I often prepare yogurt at home and use store brought yogurt only if I need to get a new starter, or at times when I am out of yogurt and need it immediately for my cooking. Store bought yogurt often has gelatin/pectin mixed in it to enhance the thickness consistency of it, which is very bad news for both non-vegetarians as well as Muslims, because gelatin is not Halal.
To prepare yogurt you can either use full fat whole milk or skimmed milk, or milk prepared from milk powder, it is your wish. Yogurt from whole milk or full fat milk is definitely thicker and much creamier. The proportion I use to make yogurt is 2 tablespoons of starter yogurt to every 1 litre of milk.
Note: Make sure you sterilize all the containers and utensils you are using while preparing yogurt
Heat milk until it reaches 180°F/80°C either in the microwave or on stove. Set aside for a few minutes. Let it cool down until the milk is just lukewarm, you should be able to tolerate the heat of the milk on your finger for about 20 seconds or a thermometer inserted should read between 115°F/46°C (if the milk is too hot or cold, yogurt/dahi will not properly set). Stir in yogurt, either commercial or some of your previous batch, 2 tbsp for each quart or liter of milk. Cover and wrap the container in kitchen towel . Keep it undisturbed to ferment in a constant warm and dark place for around 2-4 hours or overnight. Once set, refrigerate the yogurt to store. Its consistency will firm as it chills in the refrigerator and then slowly continues to acidify. The longer the yogurt is stored, the sourer it becomes
Always save some yogurt as it can be used as a starter for the next batch.
In places where it is warm and humid, making yogurt is quite easy and does not require much attention. You can cover the bowl with the yogurt starter and leave it on your countertop, undisturbed for it to set in around 8 hours.
Tip: As I currently live in Toronto where the temperatures are usually very chilly during winters, what I do is put the bowl of lukewarm milk on a heating vent and add the yogurt starter, mix it well and cover the bowl with a lid. Wrap the bowl in a towel and leave it to set, undisturbed, for about 6-8 hours or overnight. You will get thick and creamy yogurt by morning.
Some of my friends even use a heating pad at medium heat, below the container in which you are setting the yogurt for a constant supply of heat to aid in its formation.
Tip: Many a times it happens that you end up with failed yogurt. You discover that the yogurt has not set at all, and it is just like milk, and you discard the whole thing.
Instead of discarding it, you can prepare two Indian milk products from it:
1. Daan-e-daar Khoa (Granular Khoa): Pour the failed yogurt in a saucepan at medium heat and add about 1 tbsp of lemon juice (to 2 cups of failed yogurt) to curdle the milk and continue cooking. Keep stirring the milk and cook until most of the moisture has been evaporated and the milk is reduced to dry lumpy texture. Remove from heat and transfer to a cup and let cool. Once cool, refrigerate it for a hour so that it thickens/hardens. Remove the prepared Khoa from the refrigerator transfer to a zip-lock sandwich bag and freeze to store for future use, or use immediately.
2. Paneer: Pour the failed yogurt in a saucepan at medium heat and add about 1 tbsp of lemon juice (to 2 cups of failed yogurt) to curdle the milk and continue cooking milk for a few minutes until you see the milk has curdled completely. Carefully strain the curdled milk through the sieve lined with the muslin cloth. Let the whey collect in the bottom saucepan. The whey is highly nutritious. Store it to use later on in other curries instead of water (at this stage if you wish, you can experiment and add a few flavors that you like to the curds in the muslin cloth, like dried herbs, etc. Mix the dried herbs well with the curds and continue). Later, lift the edges of the cloth and tie the corners of the cloth into a bag completely enclosing the curds. Remove the sieve from saucepan and place it in the sink. Place the bag of curds back in the sieve. Set aside under a heavy weight for about 3-4 hours to press to a flat shape about 2 cm thick. Later, transfer the Paneer block to a zip-lock packet and store refrigerated. Use within a week.