This post is for all you knife and steel geeks out there.
“What is a burr?” Good question. The short answer is that a burr is just a bit of metal along the knife edge. You won’t likely get maximum sharpness without sharpening the edge to the point where there is a burr. And ironically, you definitely will not get maximum sharpness without then removing the burr.
Here’s how it works…
Steel is malleable so, as you sharpen one side, some material ends up hanging on to the apex (the very edge of the blade) and it folds over to the other side a bit. That is referred to as a “burr” or “wire”. This will happen f you sharpened it right up to the apex and you want it to happen all the way down the knife edge. Then you sharpen the opposite side and the burr bends back over to the other side. If you have sharpened the edge to a burr, you’re about to get the blade really sharp.
The burr is an indicator that you have not left a microscopically flat surface at the edge (a bald spot). It means that you have sharpened the blade all the way up to the edge leaving a nice sharp angle. However, as long as the burr is there, the knife won’t be as sharp as it could be. The burr must be removed to expose the apex of the blade (the part that really cuts) for maximum sharpness.
Here’s what a burr looks like at 60x magnification. The picture on the left is a very even burr and the picture on the right is an example of the burr separating as a wire. Both of these pictures were taken at different sections of the same blade after sharpening with a 400 grit water stone.
Evenly distributed burr at 60x mag
Uneven burr at 60x mag
Now see what the blade looks like after stropping. Both pictures are of the same blade as before. The picture on the left is the same as above (400 grit stone) except it has been stropped. The burr is gone and the blade is perfectly usable in the kitchen.
The picture on the right shows the blade after having been sharpened with 1000 grit stone and then stropping. I regularly take good knives up to a 3000 grit stone and then strop to get a nice polished apex.
Sharpened with 400 grit stone and then stropped. No burr after stropping. 60x mag.
Sharpened with 1,000 grit stone and then stropped. Edge is even cleaner. 60x mag.
You may ask, “why does this matter if they all cut fine?”
Or maybe, “can you tell the difference?”
Fair questions. I think you can tell the difference between sharpening at 400 & 1000. And sometimes you can tell whether the blade has been stropped or not when cutting things like tomatoes & bell peppers. But here are the main 2 reasons that I’ve taken the time to make this post.
- The knife sharpened with 1000+ grit stones and then stropped is far sharper.
It requires less effort to use and it’s going to remain sharp longer than one that has not stropped.
- I want you to know how much attention to detail I give when it comes to sharpening your knife. My objective is that you actually enjoy using your knife every time you cook.
I hope you found this interesting. If you would like to see a post about a specific topic, please let me know at: SharpensKnives@gmail.com.