The Coffee Mug Trick That Can Save a Dull Knife in Minutes
Having a sharp knife is essential for both precision and safety. The sharper a knife, the easier it bites into food, fabric, wood, or any other target material, while a dull blade may need to be forced through. Dull blades are also more likely to slip, especially when used on a firm or slick surface, so it is essential to keep your knives sharp. But what if you don’t have a sharpener to use? Keep reading to learn how to sharpen a knife without a sharpener.
Can You Sharpen a Knife Without a Sharpener?
Not every home cook has a sharpener readily available, and if you find yourself out at a campsite or in an RV, then you might be stuck trying to find an alternative to a traditional knife sharpener. “Knife sharpeners can make things quicker and possibly more convenient, but it's definitely possible to sharpen a knife without a sharpener,” says Katie Vine, professional recipe developer, cook, and owner of Dinners Done Quick.
Related: How to Sharpen Kitchen Knives at Home for Safe, Efficient Cutting
How to Sharpen a Knife Without a Sharpener
Ceramic Mug or Plate
When you don’t have a sharpener at home, there is a simple tool that most people will have readily available in just about any kitchen. Vine says, “my first go-to option probably everyone has at home already: a coffee mug! All you have to do is flip it over and find that kind of course unfinished ring on the bottom of the mug. Hold the knife at about a 20 degree angle, and pull it from the back of the blade to the front. Make sure to flip the knife over and get both sides. Usually about 10 strokes is good, but you can do more as needed.”
Fine-Grit Sandpaper
You may not have a sharpener readily available in the workshop, but if you have fine-grit sandpaper on hand, then you can sharpen your knives relatively easily. Shanna Jantz Kemp, knife maker at Jantz Supply Inc, says that “fine-grit sandpaper will work well. Lay it flat on a hard surface and pull the blade across it at a consistent angle, alternating sides regularly. It’s a simple way to remove small amounts of metal and refine the edge.”
Related: How to Find the Correct Knife Sharpening Angle for Kitchen, Pocket, and Outdoor Knives
Flat Stone
If you are out at a campsite, you can find a simple sharpening tool in just about any forest. Vine says that, “the other option I like is a flat stone. You'll just need a flat river stone, slate, or something similar.”
Once you have your stone, hold the knife at about a 20 degree angle, then pull the knife from the back of the blade to the front along the flat stone. Do this for about 10 strokes or until you feel a burr being raised, then flip the knife over to do the other side so that you sharpen the blade evenly.
Leather Belt
You should also consider knife maintenance and polishing when you are looking for non-traditional methods for keeping your blades sharp. “A leather belt can be used as a strop rather than a sharpener. Pull the blade spine-first along the belt. This helps to realign the edge and is ideal for maintaining sharpness,” explains Jantz.
Related: The Secret to Razor-Sharp Knives Most Home Cooks Skip
How to Avoid Common Mistakes When Sharpening a Knife Without a Sharpener
When you decide to sharpen a knife without a sharpener, there are several common mistakes that may occur. “The biggest mistake you can make is using too much pressure. Sharpening should be controlled and deliberate; forcing the blade increases the risk of damage and injury,” notes Jantz.
You should also keep a consistent angle when you are sharpening. If the angle changes throughout the sharpening process, the edge will be uneven and will dull quickly. Another common mistake is to only sharpen one side of the blade. You need to make sure to switch between sides evenly while you are sharpening to keep the edge centered. The only exception to this is if you are sharpening a blade with a single edge, like a Japanese filleting knife.
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Can Sharpening a Knife Without a Sharpener Cause Damage?
Knife sharpeners are the go-to tool for professional cooks, chefs, and even outdoors experts, so it should come as no surprise that when you use a tool that is not specifically made for sharpening knives, there is a higher risk of something going wrong.
Vine states that, “it definitely can cause damage to sharpen a knife without a sharpener, which is why a lot of folks stick to sharpeners. The most common issue is unevenness in the blade and/or bending/rounding the tip, caused by uneven pressure, unequal passes, or just rushing things.”
How to Tell If Your Knife is Sharp
There are several tests you can perform to tell if your knife is sharp. “A simple paper test works well. A sharp knife should slice cleanly through a sheet of paper without snagging or tearing. Another reliable test is cutting a tomato. If the blade breaks the skin easily without needing pressure, it’s sharp,” explains Jantz. You can also perform a basic visual inspection by looking at the knife edge under a light. If you see reflection along the edge, then this is usually a sign that the knife is dull and requires further sharpening.