Whenever I ask someone this question, 'How to make curd?' pat comes the reply, add some curd to milk, it will ferment and become curd the next day.
What if there is no curd at all at home? What if I cannot borrow some curd from neighbours either?
How did the person who made curd for the first time ever in the world, make curd without curd?
Could some one help please?
Namaskar.
Curds doubtless can be made with many types of milk, but here we shall speak about cow milk, and as an addendum, briefly describe KEFIR, a product as beneficial as yoghurt and more easily digestible by some.
Yoghurt can be prepared by several types of cultures of Lactobacillus bulgaricus, Streptomyces spp. and many others, each of which imparts some specific properties. Swiss yoghurt is prepared to have a slightly mucilaginous [slimy] texture, whereas we Indians like crisp, clean firm curds. South Indian yoghurt is slightly different in taste than North Indian, and that from Bengal, even the plain forms. Indeed, the CFTRI, Mysore, offers 2 starter cultures in dry, packages forms, one called South Indian, the other, North Indian yoghurt starter culture. These create the best Indian-style yoghurts.
It is difficult to keep a starter culture going for long in the exact original form, because natural changes occur in the bacterial populations. However, it is possible to find excellent organic yoghurts in the USA, often made by local dairies, from which one can take a new start.
That said, yoghurt is created by bacteria that are thermophilic, i.e. heat-loving. Other fermented milks proceed at lower temperatures, but the milk for yoghurt need to be brought to a boil. There is a custom in parts of the Northern plains to bring to a frothing boil about 3 times, and then place it in an earthen or other appropriate vessel. While cooling, the surface is sort of whipped with a fork to raise a tiny froth, before the full cooling is allowed. Perhaps this prevents the formation of the skin on cow's milk, which is treasured for making butter otherwise. I do not know, but it is frequently done to buffalo milk, which lacks some of the kappa proteins cow milk has.
Cooling is a relative term. Yoghurt bacteria thrive best at a steady temperature of 110-112 Fahrenheit. If we innoculate the milk with a small quantity of culture at exactly this temperature and pour this into a wide-mouthed insulated steel bottle nowadays conveniently sold by Japanese and Taiwanese vendors, it will keep the milk at the desired temperature and the yoghurt will set in a few hours. The longer we keep it at the fermentation temperature, the tarter it will become. When we refrigerate it, fermentation will slow, but not stop.
Homemade yoghurt is not as thick as commercial brands that contain various additives. By hanging it in a fine cloth bag, or fine plastic mesh strainer, we get hung yoghurt or labneh, useful for many purposes. Full-fat milk, 3.5% butterfat will give a richer yoghurt than 2%, 1%, or skim milk. These latter can be enriched with non-fat dry milk powder, to increase the amount of milk solids and ensure a thicker curd. Your reaction to the taste will depend on many factors!!
You can purchase yoghurt cultures of different types online or find them in health food places.
Kefir is a fermented milk made at mid-range temperatures, around 70-80F. The starter cultures can be purchased in a dry powder, which will produce Kefir for only a limited number of cycles, about 6.
Or, Kefir starter can be purchased as the hydrated or dehydrated MOTHER GRAINS, which are very complex assemblages of microbes that continue to produce kefir indefinitely, and need to be fed with milk to stay alive.
When the mother grains are purchased dehydrated, they come with instructions on how to very gradually hydrate them in milk over several days. After that, they become fully active. They are placed in a small jar of milk, for example, and kept in a warmish location overnight, covered with a clean, permeable top, e.g. paper coffee filter. After the appropriate time, the product is strained through a fine-mesh PLASTIC strainer, and the Kefir is refrigerated for a few hours to thicken. The remaining mother grains are placed in fresh milk and the cycle repeats.
This is a most delightful drink. You can use it to make smoothies, blend it with West Indian avocadoes for batidos, make banana-walnut smoothies, etc. My favorite food is plain low-fat kefir poured over converted rice, with flame-roasted black-pepper papads, and red chili Priya pickles! Enjoy!