Sharpening with a Whetstone – PostKnife

Sharpening with a Whetstone

Whetstone sharpening


Sharpening your knives at home with a whetstone involves the same principles as having them sharpened by a knife service like PostKnife. In a basic sense, you are removing material from the edge of the knife blade by grinding on a series of stones, starting with low-grit stones and gradually moving towards finer, high-grit stones. People often use what’s known as a ‘tri-stone’ sharpener. Three stones are included on a rotating block so you can easily sharpen your knife at different levels of grit. Two good brands to check out are Norton Abrasives and Victorinox


Sharpening process


Before we begin, there are many different opinions on whether to use oil or water on your whetstone before sharpening, but it’s up to you. Some prefer to wet the stones, which can help wash away metal shavings (also known as swarf) as well as allow for a smoother grind. Others prefer to use dry stones because water or oil can cause the swarf to cake into a sludge, clogging up the grit of the stone. Again, it’s up to you.


Also before we start, a side note: the only tool you should ever use with a PostKnife is your honing rod. We reshape the edge frequently, so no more sharpening is needed.


Now let’s begin!


First things first, it’s important to make sure your whetstone is secured to the surface you are working on, either with a damp cloth or a rubber mat. This is important because you will be putting pressure on the stone as you move the knife across it, and you don’t want to slip and cut yourself.


Next, place your blade on the stone (the lowest grit first). It’s important that the actual cutting edge of the blade is laid flat against the whetstone, while the rest of the blade is raised at an angle. For most chef knives this is somewhere between 15-20 degrees (less for Japanese knives) but you should check to make sure what the correct angle is for your blade.


Place your fingers across the blade, keeping them away from the sharp edge, and apply some pressure.


Now, slide the entire length of the blade along the whetstone. You can either do a circular motion, or a diagonal sliding motion, as long as the entire edge meets the whetstone.


Repeat this process 10-20 times on both sides. Be sure to do an equal amount of sharpening on either side of the blade, otherwise the angle of your edge will become uneven. Do this until your edge is as sharp as you need it.


As you remove material from the edge of your blade, you will encounter a wire edge, or burr. This is a thin line of metal that collects along the sharpest point of the edge. To remove the burr, sharpen the knife on a finer grit whetstone, or use a leather stropping block if you need to.




Now that you’ve reached the end, you may be wondering, “If I can use a whetstone, why would I use a knife sharpening service?” There are many other factors to consider when choosing the best way to have sharp knives.


For starters, a knife service like PostKnife can save you time and money. By having your knives serviced by a professional, you don’t have to worry about allocating time out of your or your staff's day for sharpening. This is especially important in commercial kitchens where food volume can be really high, and there's an entire crew that needs sharp knives. Some kitchens require all staff to provide and sharpen their own knives, and that can work, but for the vast majority of commercial kitchens, the consistency that a professional knife service provides to a busy kitchen, is really difficult to match. If you want sharp knives all the time, knife service truly is the answer.


You also don’t have to worry about doing it correctly. Sharpening knives takes skill, and when you use a knife service, you are tapping into years, generations even, of talent and craft. Rather than use flat whetstones, we sharpen our knives on standup grinding wheels. This produces a much cleaner, more precise edge, but it also takes a great amount of skill to master.


We hope this has given you some valuable information. If you’re still curious about sharp knives or a sharp knife subscription, visit our website at

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