How to choose and care for kitchen knives

Having good knives is critical in any well equipped kitchen and professional chefs usually have a set of knives that they guard jealously. So, what are the factors that determine if a knife is good or mediocre?  

Perhaps the most important factor in choosing a knife is the geometry of the blade and especially the handle. A chef may tell you that this knife or that one is the perfect knife for what you need. What’s important in choosing a knife? A lot is being made of the hardness of a blade and we will deal with that towards the end of this article. The truth and the quality of a knife is not just in the steel, it is in a variety of other factors as listed here. Most manufacturers are using steel with very similar composition and hardness so to choose a knife consider these factors below. Once you choose the right knife then it’s time to go shopping for the best deal.

How does the knife feel in your hand? This is possibly the most important factor to choosing a knife and it is entirely subjective. What works for your friend may not work for you. The only way to find this out is to do some hands on comparisons. Consider the handle material; will it get slippery while you are using it? Will it last as long as the blade? Many beautiful wood handles are being made with composites that will last as long as the knife but cheaper knives have plastic handles that get banged up and stained over time.  
Is it well balanced? Different knives will have different balancing points so there is no one right thing. A good French knife will balance right where the index finger is positioned when you hold the knife. Other knives will balance according to their use, a heavy French knife to be used to split lobsters will be heavier in the blade than the handle. Carving and boning knives will be heavier in the handle than the blade. The balance of a knife is more than an accident of geometry; properly balanced a knife is easy to use. Once again, hands on comparison is needed.

Is it too heavy for long use? Some of the best and most expensive knives on the market are very heavy with thick blades and heavy forged bolsters.

These knives are ideal for short term use and for when you can use the weight to help the job at hand. These are best at splitting a lobster or chopping up vegetables where the weight can do the job. If a heavy knife is razor sharp, the weight alone will slice through a soft tomato. The trouble is that all that weight is tiring to use for a long job. Choose a knife that won’t wear you out.
Alternatively a stamped blade knife with good quality steel can be light enough to use for a long time. The balance and light weight makes a knife like this easier to use and easier to finesse through some fine details. Observe the French knives in the photo above; the blade is wide so that you can wrap your fingers around the handle without scraping your fingers on the cutting board while you chop. This can be very important if you need to use the knife to cut a lot of vegetables.

Is the blade shape right for how you want to use the knife? There are many different knife styles now and they all have pros and cons. Most chefs are still using the classic French Knife for all around general kitchen use. A French knife has a slight curve to the blade which makes it ideal to rock up and down. You chop by using the curve as a pivot point. French knives also have a small point that makes it easier to use to cut or pierce small items.
A Chinese Cleaver type knife is more often used by lifting the point of the knife rather than rocking it. If it has a light blade it can be very easy to use because the weight is concentrated behind the entire blade rather than having a light point. This knife is ideal for picking up what you just cut, use it like a spatula. Chinese knives are among the few that are still available with carbon steel blades and that alone makes a strong case for buying this type of knife. A Santoku knife is good for people with small hands or those who prefer a lighter knife, it usually has harder steel than a French knife and may have a hollow grind blade which may chip if used incorrectly, A Santoku is used in the same manner as the Chinese cleaver.

Knives for specific uses The rest of your tool box of knives depends on your type of cooking. If you want to save money by boning your own chicken you’ll need a stiff bladed boning knife. If you buy or catch your own fish you will need a flexible boning knife. You’ll almost surely need a serrated blade knife for fruits and breads. For roasts you will need a carving knife. Carving knives are the only knife I recommend with a hollow ground blade. In fact a hollow ground blade is usually a sign of an inferior knife but not for carvers. There are two advantages to hollow ground blades, 1,) the blade will be lighter weight and 2.) food will be less likely to stick to the blade. The disadvantage of hollow ground blades is that it makes a knife more delicate and easier to break, not a good choice for a knife you want to use for chopping.

Finally to keep your knives sharp you’ll need a steel Remember a steel is not for sharpening but rather it is for keeping your knives sharp. A blade in use tends to roll the edge to one side or the other, the steel brings the edge back into alignment with the knife so the edge that lasts longer than it would without using a steel.

Many knife manufacturers indicate the Rockwell hardness of their knife blades. This measurement indicates the hardness of the steel used. A diamond tipped probe is forced into the steel then the depth of penetration for a given amount of force is measured and converted to a scale of relative hardness. This scale is called the Rockwell C scale. The hardness rating is usually abbreviated Rc.

Ceramic blades are essentially rocks and the Rockwell scale doesn’t work for these so, mohs is used for those knives only. The rest of the time, the Rc scale applies.

For many years knives were only made from high carbon steel with 1% carbon giving these knives excellent characteristics, easy to sharpen and good edge holding ability. If you don’t mind the staining of carbon steel knives these are an excellent choice and economical to boot.

More recently most knives are made from high carbon stainless steel to the point that it is now difficult to find knives that are not stainless.

The latest thing is ceramic blade knives and they can have extraordinary hardness, retaining their sharpness for a very long time. Ceramic knives do get dull in spite of what the commercials say and they are very difficult to sharpen, also, depending on the manufacturer ceramic knives may have a slight porosity and will stain, not all brands stain though.

The Steel When the manufacturer reveals the details of the composition of the steel you will see a number like this: x50CR MO (composition with a Rockwell hardness of) 55-56 HRC

X means stainless.
45 or 50 means .45% or .50% carbon.
Cr Mo V means the total percentage of chromium, molybdenum, and vanadium, in this case 15%.
Most carbon steel and high carbon stainless steels have the same basic amount of carbon: .45% to .5%. The carbon gives the steel hardness, the more carbon, the harder the knife metal. The difference between two metals is the amount of chromium, molybdenum, and vanadium. These metals give stainless steel its stainless qualities, added compression hardness and tensile strength.

What the numbers don’t tell you is how well the steel has been hardened. Hardening steel is a process of heating it cherry red, quenching it quickly and repeating the process but quenching it more slowly. The second process is called tempering and it softens the steel a little bit to make it less brittle. The hardening, tempering process is where the different knife companies stand out, a choice has to be made as to how hard steel should be versus how resilient it should be. A knife that has very hard steel will break the first time it is dropped but a knife that is too well tempered won’t hold an edge. There are lots of good manufacturers of chef’s knives and at the risk of offending someone Connoisseur knives by Dexter Russel have among the best steels available.

SHUN, MAC and GLOBAL are now making very high carbon stainless steel with total carbon of 1.0%, this makes a very hard and sharp knife that may be a bit more brittle. These knives are more likely to break if you drop them but they will hold a sharp edge for a long time.

Cost  Quality knives can be very expensive but you don’t have to spend a fortune to buy a good knife. The more expensive knives are the hand forged knives with heavy bolsters (The bolster is the lip on the heel of the blade, between your hand and the blade) These knives are difficult to sharpen and frequently end up with a dip in the blade where it should be straight, a stamped blade won’t do that and is cheaper too. Expect to pay over a hundred dollars for a forged French knife and half that for a stamped knife.

Caring for your knives Very little attention is needed to get a lifetime of use out of your knives.
1)  Wash with warm soapy water, rinse and dry before putting them away. Food left on a knife blade will corrode even the best stainless steel so keep them clean
2) Never put them in a dishwasher, the heat and caustic chemicals will destroy the handles and corrode the blades over time
3) Don’t toss knives in a drawer with other knives. Buy and use a decent knife rack, preferably one that lets the knives hang freely, a knife block is unsanitary.
4) Sharpen when necessary, each sharpening removes some metal but keep your knives sharp, dull knives cause accidents.
5) Invest in a good sharpening system and learn how to use it. Chef’s Choice does a very good job but requires a knack to use well, or for a fraction of the cost buy a two sided carborundum oil stone.