Knife sharpening, what you need to know first
Hi All,
So one day you decide that you want to invest on a good kitchen knife, or maybe a collection of them. This is a good thing. High quality knives make food preparation a true pleasure. Cuts are effortless, clean and precise. All this makes for beautiful food.
Good knives are not cheap; they are investments that with good care will last a lifetime. One of the most important care items is of course the edge. Although good knives hold their edge a lot longer, all knives get dull with use. Maintaining the sharp edge is the most important maintenance item on a good quality knife. Never let the knife get really dull....
So, sooner or later you will have to sharpen that beautiful knife. What to do….
The first and most important thing is to find the angles of your edge. Most all knifes have different angles, especially Japanese knives which can not only have different edge angles but also different edge and blade geometries. Finding the angles is easy:
Take your knife and hold the blade flat on your cutting board with the handle off the side of the board. Slowly, move the blade in the direction of the edge while slowly raising the spine (the top of the blade) off the cutting board. At a certain point the edge will catch on the board and stop the knife. Observe the distance between the spine and the board. Slightly less than that distance is the angle of your edge. Slightly less because the edge already bit into the board so you have to back down a little bit from there to sharpen the knife.
Repeat for the other side of the blade. Why? Because some knives (especially Japanese knives) are built with different edge geometries.
Here are three images showing how this works with my Santoku knife:
1) The Starting point with the knife flat on the board
2) The edge has caught the board. The knife is so sharp that it actually takes chunks off the board. Notice the angle – it’s low, about 10 degrees or less
3) Same process on the other side of the blade. Notice this angle is much higher, about 30 degrees.
This shows my Santoku has an asymmetrical edge. If I took a stone to it and sharpened the edge like a western knife (same angle on both sides) I would ruin the factory set edge.
To see a number of different edges and geometries look at this discussion thread. It’s the best one I could find.
http://www.cheftalk.com/t/63443/bevels-double-bevels-angles-im-confused
If you guys want me to I’ll post something on sharpening stones etc. Don’t use a steel to maintain the edge. Steels are very imprecise and are best used with softer steel Western style knives that have equal 20 degree angles. If you still decide to use a steel get a high quality ceramic steel.
Best,
Jose