sour yoghurt

Sour yoghurt is a fermented dairy product produced by the bacterial fermentation of milk, resulting in a tangy, acidic cultured product with a thick, creamy consistency. The fermentation process, typically involving Lactobacillus bulgaricus and Streptococcus thermophilus cultures (often supplemented with additional cultures), converts lactose into lactic acid, lowering the pH and developing the characteristic sour flavor profile. Sour yoghurt varieties range from thin and pourable to thick and spoonable, with fat content typically between 2–10%, depending on the milk source and production method. Regional variations include Greek-style strained yoghurt (higher protein concentration), Icelandic skyr, Bulgarian yoghurt, and Middle Eastern labneh (strained to cream-like consistency).

Sour yoghurt serves as both a condiment and a cooking ingredient across Middle Eastern, Mediterranean, South Asian, and Eastern European cuisines. It is used as a base for dressings, sauces (such as tzatziki), marinades for meat, and as an accompaniment to grain bowls, curries, and roasted vegetables. The acidity and tang complement rich or spiced dishes, while its creamy texture enriches soups and baked goods. Common applications include topping for baked potatoes, layering in parfaits, and tenderizing agent in marinades. In baking, sour yoghurt adds moisture and slight sourness to breads, cakes, and pancakes.