Why is Greek yogurt thicker than regular yogurt?

Greek yogurt is thicker than regular yogurt primarily because whey is removed during the straining process. This straining allows for a denser product by eliminating a significant amount of the liquid (whey) that is present in regular yogurt. The resulting texture is creamy and thick, which is characteristic of Greek yogurt.

In contrast, while whole milk can contribute to a richer flavor and creamier texture, it does not specifically account for the thickness difference between Greek and regular yogurt. The number of cultures used may affect the yogurt's flavor and health benefits but does not determine its thickness. Similarly, added gelatin can thicken yogurt but is not a standard part of traditional Greek yogurt production, which relies on the natural straining process. Thus, the removal of whey is the key factor that defines the thickness of Greek yogurt.