Red Seal Cook

Answer: B - The benefit of oil on a whetstone is that it creates more friction than regular water enabling the blade to sharpen faster and more effectively. There is also an argument to be made for oil’s ability to prevent rust on the blade, however most blades are made with carbon steel and don’t rust easily anyway. Oil does go rancid over time, and thus using oil on the stone opens up the risk of rancidity. While water doesn’t create as strong a suction force, it works well enough that most people choose to simply stick to water. Once you’ve used oil on a whetstone, you cannot go back to using water.