One of the most asked questions at the shop is how one should go about keeping their knife sharp at home, especially after having it professionally sharpened. There are lots of home-use sharpening gadgets out there, but our favorite tool to use at home after professional sharpening is the humble honing rod, also known as a sharpening steel (you know, that round thing that you keep in the drawer and forget you have).
Most people are familiar with sharpening steels, which is steel rod with very small grooves in it, like a fine file. There are also honing rods made out of other materials, such as fine ceramic, or diamond coating.
After you have your knife sharpened, you have a completely fresh sharp edge, that will hold for a while, but at some point, you will definitely feel like that peak sharpness is just not there anymore. If you are inclined to feel the edge to test for dullness, brush your fingers away from the edge to see if there is a rolled edge or burr there. You can hold the knife in some light and see the dull spot reflect light. If so, this would be a good time to lightly hone your knife. The honing rod will push the existing but misaligned edge back to where it needs to be.
The main important factor of using honing rod correctly is maintaining a consistent angle. Too high and angle (30 degrees and up) may get the knife sharp a few times, but it will eventually ruin the edge geometry prematurely. Too low, and you most likely start to scratch up the face of the knife, although, we feel that too low is better than too high if you care about sharpness more than cosmetics. For most knives, shoot for 15-20 degrees on each side. Hold the honing rod straight upside down with the tip on a cutting board, and hold the heel of the knife at the desired angle and slice downward as you draw the knife toward yourself. Alternate strokes on each side of the knife. You might feel a little resistance on the first few pulls, and then it should feel smooth at some point. Usually 10 times on each side is enough. As with most things, the proof is in the pudding, and if you nailed the angle, the edge should feel much sharper than it did. Remember, honing you knife also wears the edge down each time, and at some point, you will find that honing your knife just doesn't get it cutting, so a full sharpening may be in order.
TLDR: Honing rods re-align the edge. Pass the knife blade over the rod at a 15-20 degree angle lightly, about 10 times on each side.