In ancient Viking kitchens, a built-in yogurt maker known as a 'skyr barrel' was used. Skyr was a traditional Icelandic yogurt made by fermenting milk. Vikings would fill the skyr barrel with milk, add a small amount of skyr as a starter culture, and then place it in a cool area of the kitchen. The skyr barrel would maintain the ideal temperature for fermentation, resulting in a thick and creamy yogurt.
