You see, sharpening is more than just running your knife over a whetstone several times every other week. Theoretically speaking a few passes over a sharpening stone should do a “good enough job”, however; to truly master the process of sharpening requires intimate knowledge of several facets, one of which is the burr.
Today we’ll discuss what exactly is burr and why it matters for proper blade sharpening.
What exactly is a burr? The word does indeed sound a bit funny; however, burr formation is the core component of the knife sharpening process. Put simply, the burr is raised metal. While sharpening the blade, burr formation occurs on the opposing side of the blade. The key purpose of the burr formation is to let you know that the sharpening process is having the desired impact on the blade,
Its importance: Burr formation is an indication that the side you’re working on has properly sharpened and needs to be switched. You must continue sharpening until proper burr formation has been achieved. Otherwise, you’ll have a blade that isn’t optimally sharp.
Forming a burr: Burr formation could be a bit tricky, especially if you’re trying to work the bevel with a lower grit or a coarse sharpening stone. The hard bit while working with lower grit stones is actually determining the precise amount of pressure required for burr formation. Overexertion with coarse stone usually results in a badly shaped burr.
More than necessary force also affects your ability to maintain a consistent angle, which is crucial for burr formation. You may be able to form a “wire edge” – a burr that points downward. However, there’s a bit of a tradeoff here. A wire edge is super sharp but you tend to give up on strength, which makes it susceptible to chipping. If that happens, you’ll be left with a knife that is blunt.
Patience is your best friend here because it will give you the best of both worlds when it comes to burr strength and sharpness. Ideally, you should be using light pressure and focus on maintaining an even angle while forming the burr.
Once you have achieved a burr on both sides, you then need to progressively use higher grit stones or finer stones to “polish off” the burr. The finer stones facilitate the formation of a very fine burr, which is an indication of thorough and complete blade sharpening job.