Sharp knives are essential to being productive in the kitchen, and perhaps even more importantly your own safety. Cutting carrots with a dull knife, envisioning your finger rolling under the blade because you have to use so much extra force is frightening. Don’t misunderstand, sharp knives can make you bleed, but they offer control and cut easily enough keeping you safer.
Watch as Allen Bixby shows each type of sharpener and how to use them; or read on.
Sharpening a knife consists of rubbing an abrasive device across the edge of the blade to smooth, straighten and polish. The contact needs to be done at a specific angle to create the even bevel of a well sharpened knife. When you have finished you should be able to look down the edge of the blade, along a bright strip of polished metal.
Why the angle matters
As mentioned, a sharp knife has a beveled edge at an acute angle, visibly different than the surface of the blade above it. Standard knife angle is at 20 degrees, measured relative to the plane of the blade. The ‘inclusive’ number, both sides of the bevel, is forty degrees. Japanese steel is often taken to 17 or 18 degrees. Outdoor tools and such are often taken to a 25 degree bevel.
|30° to 35°|
|25° to 30°|
|18° - 25°|
|12° to 18°|
The alternative is what we might call a razor’s edge. By taking such a flat angle, 10 degrees or less, you create a very sharp but fragile edge on the blade. That is why you will see it on scalpels and straight razors, for example. Neither of those are used on a cutting board. Even a 20 degree beveled will begin to curl when used on a board, which is why you need to hone them regularly. The 25 degree angle is used for heavy duty cutting implements, axes and the like.
Hone versus sharpening
Honing is what you do between sharpening to maintain your blades. The biggest difference is that sharpening actually removes a thin layer of metal to bring back the proper edge. Honing typically does not, it straightens and smooths out the blade. When done properly, honing can significantly extend the time between sharpening sessions, particularly if you touch up your blades before every use.
We will separate the common devices that are used to hone as opposed to the devices made to sharpen your knives. We have three styles in each category, although there is a slight amount of legitimate crossover between them which we clarify.
Types of Knife Sharpeners
These come with virtually every knife set, a metal rod with a handle…although now they make them out of ceramic, they are still called a steel. Their functionality is by dragging the blade down the length of the rod. This straightens out the edge, smooths minor nicks, and polishes the metal to help cut through food better.
The technique is to draw the blade edge toward the base, almost as if you want to shave off a very fine layer of the rod. Make sure that you pull the blade across as well, to run the steel along the entire length of the blade from base to tip.
Handheld drag sharpener
For lack of an actual term, we use ‘drag sharpener’ in reference to the devices that have two surfaces at a set angle that are dragged across the edge of the blade. This first type you set the blade on its’ spine, edge up, and drag the handheld unit down the length pf the blade. This is actually a very good tool to keep your blades pristine.
Typically these have two small pieces titanium or such set into a precise angle in a device with a shielded grip. One advantage of these is that you can drag them down the blade with almost no pressure on the blade. You will actually feel the imperfections of your knife, and know exactly where to hone it for great maintenance. If you had no alternative, you can restore a somewhat used blade by applying more pressure as you drag it, and actually taking off a slight amount of metal. But these devices are really intended solely for honing.
A fairly simple device, you usually have a handle to hold it stable and slots through which you drag the knives. A single slot unit is for honing, multiple slots will open up many more options for you. Everything from 3 and 4 different grinds to electric units with spinning grindstones.
These can be relatively effective for actual sharpening, but they are not especially precise in how the slots cradle the knife relative to the surfaces. And the electric grindstones are known for eating blades, significantly shortening your usable life span. Our recommendation is to use these for honing and touching up your blades, use more effective methods when the time comes to sharpen.
One definition of ‘whet’ is to sharpen by rubbing on or with something. Pretty straightforward description that this a stone for that purpose. It gets phonetically confusing because in fact they do work better when ‘wet’, either water or oil. The fluid floats away the metal finings, which keeps the pores in the stone from clogging which diminishes the ability of the surface to sharpen. Properly used, you will get almost identical results from water or oil dampened stones. Oil stones will experience less wear and offer a longer usable life span.
At a minimum, most whetstones have different surfaces on each side, a more coarse grinding side and a finer side for polishing. Large commercial stone set ups often have a long three sided triangle and an oil reservoir underneath. Ideally you hold the blade at the proper angle, apply about 6 pounds pf pressure when sharpening your first passes on the stone, 4 pounds of pressure for honing. Like most sharpening, you push the blade edge forward along the surface of the stone.
Precision whetstone devices
This is a recent iteration of tools to sharpen knives. Typically the knife is clamped to a fixed position and the stone is set at the proper relative angle. The device holds that all in place as you work the stone along the blade. They will have an assortment of stone strips in different grits for grinding and polishing. Often 10 or more, so it can even get a bit daunting. Ideally just use 3 or 4 stones from coarse to fine to get solid results.
When you have a stone wet, you really just want it damp, not dripping. These systems offer that very easily. The stone strips can be placed in a tall glass of water for 5 minutes before use and they are good to go. They are also fairly easy to swap out when switching to a different grit. You do need a phone app in most cases to get the angle set, but once in place it will stay there throughout your sharpening session.
Electric sharpening devices
There are grinding type electric sharpeners all over the market, a good friend was a meat cutter and used one of these. It showed, because his older blades had lost noticeable blade to the grinding process. A professional knife sharpener will use a spinning grind wheel, but unless you know the exact pressure to apply you risk literally grinding away your blades.
Enter the electric belt style home sharpeners. With some give in the belts you can greatly diminish the wear on your knives. They are also offering multiple grit belts so that you can work your knife through a proper sequence of grinds to get a sharp polished edge result. These aren’t foolproof, but they certainly are less impactful than a grinder type of sharpener and will work for every skill level of knife sharpening.
It is extremely important to have sharp knives when working in the kitchen for both safety and effectiveness. There are many ways to get there, and the overriding message we want to convey is to find what you like and be sure to use it regularly.