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The following information is provided
courtesy of The Catering Equipment Suppliers Association.
Understanding
Kitchen knives
As with cooking pans, kitchen knives
reflect designs and cooking techniques that follow tradition in
the part of the world where they were developed. As with all
professional kitchen equipment, quality is reflected in the
price.
The most common way of making a
knife blade, bolster and tang is to drop-forge it, which means
putting a piece of red-hot stainless steel in the lower half of
a mould and stamping down on it with a huge force to form the
basis of the knife. Some manufacturers prefer to fuse together
three different grades of metal for the three parts of the
knife, believing that each part needs a different steel
quality.
The blade is then tempered with heat
to create extra hardness, polished, fitted with a handle and
sharpened. The higher quality the steel, the sharper will be the
edge and the longer it will remain without needing
re-sharpening. Low grade stainless steel kitchen knives are
unable to hold an edge much beyond first using and hand-steeling
will fail to bring back the edge. It pays in the long term
to invest in quality kitchen knives.
The traditional way to fit a handle
is to rivet a solid handle in two halves, but cheaper knives
will come with a single-formed solid plastic handle. A plastic
handle is not always an indicator or poor quality blade steel
any more than riveted handles are a signal of high quality.
Balance is
very important in kitchen knife construction. There should be a
good counter-balance between handle and blade so that the knife
sits level in the hand for quick and comfortable working.
There are basically two styles of kitchen knives; Eastern and
Western. Eastern style knives such as Japanese are made
from very hard steel, the blades are significantly thinner,
producing a lighter weight knife and the bevel angles are more
acute. These knives will hold an edge for longer, but will also
take longer to sharpen. They are good for cutting where accuracy
is important, such as preparing Sushi or doing decorative work.
The Japanese also make knives that incorporate a chisel grind.
This is a bevel on one side with the other side flat. These are
usually made from what is called sandwiched steels, where a hard
steel for edge retention is sandwiched between soft steel or
even iron to provide better toughness. They do an
excellent job with Eastern style cooking where there is much
fine chopping, but their sharpness is also a feature many
Western chefs like.
Western knives are made from tough steel, but slightly softer
than Japanese knives which makes them easier to maintain a sharp
edge on. They tend to be thicker and heavier with a more
obtuse bevel angle. These are perfect for chopping and for those
jobs where a heavier knife is an advantage.
There are three types of steel used in kitchen knives
High carbon steel
- An excellent material, providing toughness and the ability to
take a very sharp edge. However, carbon steel is not stain
resistant. It can rust and will discolour from use. After much
use, high carbon steel kitchen knife blades will actually become
black. This discoloration is purely cosmetic and does not affect
the performance of the knife in any way.
High carbon stainless steel
- The most popular steel for kitchen knives. It has a high
content of carbon for hardness, but chromium and nickel to keep
it looking clean. High carbon stainless will take a sharp
edge and maintain it well.
Titanium enhanced knife blades will hold an edge longer than
most other steel alloys. The alloy mix allow the blades to be
heat treated to a high level of hardness. The blades are more
flexible than standard steel blades so work well for boning, and
filleting.
Ceramic is not a steel at all, but a very hard ceramic material
called zirconium oxide. These blades are so hard that they will
maintain a sharp edge for months or years with no maintenance at
all. On the negative side, they are more brittle and they
require diamond sharpening tools to maintain.
Knife styles
The range of blade designs is very
wide and this is just a selection of the more widely-used blades
designs and their use.
Cook’s knife -
The basic
kitchen knife for doing a wide range of cutting and chopping
jobs. It has a pointed blade and comes in a wide range of blade
sizes.
Turning knife -
A
short-bladed knife with a downward-pointed hooked end which
makes for easy turning of vegetables in the classic French
style.
Scalloped edge -
A
long thin knife with a scalloped edge. The scallops allows air
to pass around the blade as it cuts very thin slices making this
blade style suitable for cutting cold meats or smoked salmon.
Serrated edge -
The feature
of serrated blades is that they tear as well as cut. Narrow
serrated blades are suitable for soft foods such as tomatoes or
cucumbers. Wide serrated blades are used for cutting hot meats (carvery)
and bread.
Fish filleting knife -
This
needs to be a thin slender and slightly flexible blade to allow
for filleting of flatfish such as turbot and working around the
skeletal frame of round fish such as cod.
Hachoirs or Mezzalunas
-
These are curved blades, usually double bladed, but can be
treble bladed, with a handle at either end. They are the
traditional way of finely chopping herbs, vegetables and meat.
They can come with a specially curved wood bowl to fit the
cutter or just rocked under pressure on a chopping board. The
quality of the steel has to be very good to maintain the edge
for chopping herbs such as parsley. However, their use is not so
widespread now since food processors have become popular. Some
chefs will argue that a hachoir properly cuts herbs and meats
while a food processor pulverises them. Sharpening them is not
easy due to the closeness of the blades, another reason to buy
quality steel.
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