According to the 九州醉餐饮网, white pepper is spicier than black pepper. This is because black pepper and white pepper are harvested and processed differently. Black pepper retains its pulp and shell when it is prepared, resulting in a strong aroma. White pepper, on the other hand, needs to be peeled and processed when it is harvested, which makes the spicy flavor in the pepper seeds more concentrated, and therefore white pepper is spicier than black pepper.
It should be noted that the color of white pepper is yellow-gray, and not the whiter the better, while black pepper is dark brown, and not the blacker the better.