Screw batch steamed bun, also known as old leaven head, tastes sour and slightly sour, and has a stronger taste. Its shape is thick and flaky, and its color tends to dark yellow.

Si Kang, crispy outside and tender inside, has a strong wheat flavor and is often eaten with jam and butter. Its appearance is triangular or diamond, and its color is golden yellow.

Generally speaking, the steamed stuffed bun with screwdriver tastes thick and sour, while Si Kang tastes crisp and has a strong wheat flavor.