Curd vs. Yogurt

Curd

Curds are a dairy product obtained by coagulating milk in a process called curdling. The coagulation can be caused by adding rennet or any edible acidic substance such as lemon juice or vinegar, and then allowing it to coagulate. The increased acidity causes the milk proteins (casein) to tangle into solid masses, or curds. Milk that has been left to sour (raw milk alone or pasteurized milk with added lactic acid bacteria) will also naturally produce curds, and sour milk cheeses are produced this way. Producing cheese curds is one of the first steps in cheesemaking; the curds are pressed and drained to varying amounts for different styles of cheese and different secondary agents (molds for blue cheeses, etc.) are introduced before the desired aging finishes the cheese. The remaining liquid, which contains only whey proteins, is the whey. In cow’s milk, 90 percent of the proteins are caseins.

In Indian English, used only in the Indian subcontinent, curd (or curds) is used to refer to the traditional homemade yogurt known as dahi, while paneer and Chhena are used to denote curdled milk.

Yogurt

Yogurt, yoghurt or yoghourt ( or ; from Turkish: yoğurt) is a food produced by bacterial fermentation of milk. The bacteria used to make yogurt are known as yogurt cultures. The fermentation of lactose by these bacteria produces lactic acid, which acts on milk protein to give yogurt its texture and characteristic tart flavor. Cow’s milk is commonly available worldwide and, as such, is the milk most commonly used to make yogurt. Milk from water buffalo, goats, ewes, mares, camels, and yaks is also used to produce yogurt where available locally. The milk used may be homogenized or not, even pasteurized or raw. Each type of milk produces substantially different results.

Yogurt is produced using a culture of Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus bacteria. In addition, other lactobacilli and bifidobacteria are sometimes added during or after culturing yogurt. Some countries require yogurt to contain a certain amount of colony-forming units (CFU) of bacteria; in China, for example, the requirement for the number of lactobacillus bacteria is at least 1 million CFU per milliliter.To produce yogurt, milk is first heated, usually to about 85 °C (185 °F), to denature the milk proteins so that they do not form curds. After heating, the milk is allowed to cool to about 45 °C (113 °F). The bacterial culture is mixed in, and that temperature of 45 °C is maintained for 4 to 12 hours to allow fermentation to occur.

Yogurt (noun)

a semi-solid sourish food prepared from milk fermented by added bacteria, often sweetened and flavoured

“low-fat yogurt”

“frozen yogurts”