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Knife Maintenance
Vermont Cutting Boards Information Center
Kitchen Knife Maintenance
Knives
are the most important tools in the kitchen. The rule for most
kitchenware is to buy the best you can afford and then take
care of it. Fine quality knives are completely functional and
they do one thing extremely well – they cut. Their size,
their shape, the way they feel in your hand, the way they are
made, all evolved from centuries of trial, error, and old world
craftsmanship combined with new knowledge and available materials.
Fine knives are simple, heavy-duty and functional. The blade
tapers evenly from the handle to tip, and from the back of the
blade to the cutting edge. The tang, or portion of the blade
where it connects to the handle, extends into the handle where
it is either riveted or permanently bonded to the handle and
the feel is hefty. These, together with the blade’s sharpness,
add safety by reducing strain and fatigue. Fine quality knives
have a sharp cutting edge that, with proper maintenance, stays
sharp for a long time. The blade angle is consistent, they have
optimal balance and most importantly, they feel good in your
hand.
So, how do you best care for your knife? There are a couple
of steps that this requires. The first step is keeping your
knife clean. Certain food acids can stain even the most stainless
of steels. It’s good practice to wipe a knife after every
use. Lay the blade on a ?at surface, wipe one side, then the
other with a soft, damp, soapy cloth, then rinse the blade under
running water. This is safer than washing a knife in a sink
where suds may hide the blade, or in a dishwasher where the
edge can bang against other cutlery, silverware, or china. The
dishwasher can also damage the handle of certain knives.
The next step is to sharpen your knife regularly. You know
when the knife needs sharpening when the blade is dull. You
start off with a knife that is blunt which means that the edge
is worn. the goal is to make the sides of the edges meet each
other and thus form a sharp cutting edge. You achieve this by
lowering the edge bevels by grinding them with an abrasive such
as a sharpening stone : The angle of the edge is still the same
and the new edge is exactly in line with where the old one used
to be. Now to accomplish this all you need is a decent stone,
such as an 8" dual (coarse/medium) aluminium oxide stone,
6" (coarse/fine) Norton Carborundum Stone, 4" dual
folding Ez-Lap diamond (coarse/fine), or a 4" DMT diafold
(fine/super fine).
The basic method is to push your knife edge first along the
stone like you were trying to slice into it. You need to exert
a decent amount of force on the stone to get it to cut the blade
so make sure it will not move. Either clamp it, put it on a
non-skid surface, or just use a really heavy stone. The most
important part is to maintain a constant angle between the blade
and the stone. This becomes easy with practice. When you start
out you can check that you are grinding at the correct angle
by using a marker to color the edge and checking to see where
you are removing metal by seeing where the he ink has been removed.
After awhile you will be able to tell the angle is correct by
feel.
So basically you stroke the knife on the stone, pushing the
knife away from you. Then you turn the knife over and stroke
it along the stone, pulling it towards you. The critical question
of course is when do you stop doing this? How do you know when
the knife is sharpened? One method is to let the edge of the
blade rest on your thumbnail and move it in a scraping motion.
If the blade is sharp then the edge will catch in and be difficult
to move. You can also drag your finger across the edge of the
blade to feel for a burr, the sharper a blade, the more pressure
you will feel on your finger. A far less dangerous test is to
just hold the knife edge up so a light source is shining right
across. Now tilt the blade back and forth a little, if the edge
is uneven or has any nicks or chips in it then this will reflect
the light strongly and you know you still have some work to
do.
If you are satisfied that the blade is sharp then there is
only one small step left to do. You raise the angle of the blade
off the stone just a few degrees, and give the knife just a
couple of very light passes across the stone. This grinds just
the very edge of the knife and insures that the edge is at its
optimal strength and cutting ability. The reason that you do
this is to insure that any burr is ground away. A burr is a
small fold of weakened metal that can form during sharpening,
it is only about 1/20 of a mm in width. To test to see that
the burr has been removed you can use the thumbnail and finger
feeling test as described in the above testing both sides of
the blade.
