Why test a knife's sharpness using the paper test?
There are several different ways of testing how sharp your knife really is. No doubt you've seen countless "tomato" tests where those who've spent many long hours toiling away to get their chef's knife to peak condition to try and take the smallest slice of tomato off the red orb like they're trying to make a vegetarian proscuitto.
That said we find that the best way of seeing if your knife is truly as sharp as you need it is by performing similar tasks as you'll need it to. We don't see much need for a survival knife to be able to slice microns off a tomato at a time, however, it should be able to cut through rope with ease. In that same mentality we wouldn't expect a chef's knife to perform well at whittling
So that leads us back to the original question... Why do people use the paper test? In order to explain that we first have to dig briefly into the sharpening process.
What happens during sharpening?
Any knife follows the same basic principles in order to be able to cut through material, called an angle of attack. As we cover in our article "Sharpening VS Honing" these angles form a V shape that allows the magic of cutting to happen.
Over time and use the fine point of the V begins to dull and looks more like a U if you were able to see close enough. During the sharpening process stones are moved across the knife edge to take off material to return the angle back to the V shape.
Ok, Now for the paper test.
During the sharpening process (Especially if you're following our CUSH-P Method, get it FREE below), we recommend stepping up in grit of stones as you go. As you do you'll get a finer and finer point allowing for a more precise cut.
In between stones it is common to stop and run your knife across the edge of a piece of paper attempting to slice the edge of the page. If the knife has a large burr in the edge or you haven't created an even edge all the way across, the paper will tear instead of a clean cut. You're looking for a clean slice all the way through.
Note: If you choose to attempt this test we do recommend that you do so carefully. There are many ways of safely testing the sharpness of your knife, we recommend starting with a different method or finding the assistance of a professional.
