Strained yogurt, Greek yogurt, yogurt cheese, sack yogurt, or kerned yogurt is yogurt that has been strained to remove most of its whey, resulting in a thicker consistency than normal unstrained yogurt, while still preserving the distinctive sour taste of yogurt. Like many types, strained yogurt is often made from milk enriched by boiling off some water content, or by adding extra butterfat and powdered milk. In Europe and North America, it is often made from low-fat or fat-free cow's milk. In Iceland, a similar product named skyr is made.