When it comes to choosing a knife, the incredible variability of materials and designs can be overwhelming. A “cheap” knife will end up costing more in the long term, because it will break or go dull. Low-quality steels will not keep a sharp edge no matter how many hours are wasted on sharpening, and a new knife will have to be purchased every year or so.
Everyone enjoys cooking with a quality knife, but often you only notice you worked with bad knives for a long time when you start using a really good one.
The below checklist is the result of in-depth interviews with chefs from around the world and extensive research, boiling down knife selection to 5 major characteristics.
#1: Steel Chemical Composition & Tempering
Knifemakers say that steel is the soul of a knife. A blade must be hard yet flexible, tough and corrosion resistant. There are literally hundreds of different steels, each with their advantages and flaws. When it comes to choosing the best steel, it is all about choosing the best balance of the physical properties that are important to you.
Hardness is what will allow your blade to be sharp and more importantly, stay sharp. The more carbon in the steel, the harder it can be. Too little carbon and the steel will be soft and useless. Too much of it and the blade will be brittle, prone to chipping and rusting. The ideal balance is around 0.8% - 1.0% carbon content. The overwhelming majority of knives on the market contain between 0.1% and 0.3% carbon, while the Japanese 440C steel used in KOTAI knives contains 200% more carbon (0.95%).
Tempering - also called heat treatment - is what actually gives the steel its mechanical properties, like hardness, toughness and flexibility. Without the proper heat treatment, the real potential of a blade cannot be achieved. Vacuum heat treatment ensures that the steel’s molecular structure is at its best.
Toughness is what will allow your blade to survive years of abuse in the kitchen. A blade that is very sharp but chips at the slightest occasion is not our definition of a lifetime partner. The added molybdenum (0.4%) and vanadium (0.08%) combined with state-of-the-art vacuum heat treatment give KOTAI blades the extra toughness and flexibility that are crucial for a knife to last.
#2: Blade Geometry
There are as many blade shapes as knife brands, each with their own benefits for specific uses. Still, chef knives can be broadly categorised into Western knives and Japanese knives. Western knives have the advantage of heft for a more powerful cut and a curved belly made for mincing with a rocking motion. Japanese knives have thinner blades and a flatter edge, allowing precise and effortless slicing. Depending on your cooking style, one might suit you better than the other.
But for people who do not like to compromise, there is the gyuto. It is the best of both worlds, a hybrid between a German and a Japanese knife.
The slightly curved belly enables the blade to rock back and forth for fast mincing, while the blade is flat and thin enough for smooth and easy slicing.
A gyuto is easily recognised by its “pointed tip”, used by chefs for added precision.
Bevel grind is also important when choosing a knife. While sushi chefs might prefer single bevel knives (think of it as a chisel), most chefs have a preference for double bevel grinds for straight cuts and easy sharpening.
#3: Perfect Balance
Balance is not always considered when choosing a knife because it cannot be seen. But after hours of slicing, chopping and mincing, balance can definitely be felt. To optimise cutting power and minimize strain on the wrist, a knife must be hefty enough (thanks to a full tang and a quality handle) and its center of gravity must be placed strategically.
Most chefs like their knife’s center of gravity to be right above the bolster, which is where the index finger is when holding the knife with a pinch grip.
Besides balance, heft is also critical to how much you will enjoy using your knife. Heft - the weight of the knife in you hand - must be at the right level for you to optimise cutting power and minimize strain on the wrist. Too light and you will have to compensate by adding wrist tension, possibly inviting injuries. Too heavy and it will feel clumsy and tiring.
A chef knife should be perfectly balanced and feel like the natural extension of your arm.
If steel is the soul of a knife, craftsmanship is the knife’s body. And a soul without a strong body cannot achieve much.
When it comes to sturdiness and durability, a full tang is the way to go. The tang refers to the extension of the blade that goes inside the handle. There are 2 main types of tangs: full and partial. A full tang extends all the way to the end of the handle, ensuring that the blade and handle will never part. Partial tangs - where the blade metal only extends to about half the length of the handle - are cheaper to produce but more prone to loosening or even breaking after extended use.
Now there is actually a third type of tang: the hidden full tang. This type of construction is technically much more demanding to manufacture, but the result is worth the additional cost and effort. Hidden tangs are not visible from the outside; they run inside the handle before widening at the end to form a metal cap. A hidden full tang is as durable as a full tang, with the added benefit of seamless aesthetics and allowing comfortable round handles. KOTAI has developed a proprietary manufacturing technique to create a full tang knife without having to add rivets or use glue, making it 20 times more durable than other knives.
Great craftsmanship reveals itself in the smallest details, and a truly well-made knife will have a seamless construction. Small gaps between the bolster and the handle can harbor bacteria. High-end knives will have no such gaps, for optimal hygiene and durability. This can be checked by running your fingers along the handle: it should be completely smooth.
Besides the raw materials used, the difference between a high-end knife and a lower-quality option is the number of hours spent on it by the knifemaker. After grinding (giving the blade its final shape), a blade can be polished once, twice or many more times. KOTAI knives are polished by hand using 5 different wheels to obtain their distinctive “satin finishing”. Satin finishing offers excellent corrosion resistance by reducing the contact area between the steel and the air and minimizing the invisible asperities in which water could hide. As opposed to a mirror finishing, satin finishing is very hard to scratch, thus remaining beautiful throughout decades of use.
#5: Handle Shape & Material
Even though the blade is the first thing to look at when choosing a quality knife, you will (hopefully) have precious few contacts with it. On the other hand, the handle is the only part that will sit in your hand for hours and hours. Mass-produced handles are generally made of ABS or POM (plastic polymers). They tend to be slippery - especially with wet hands - and do not look premium. On the other hand, wooden handles have a timeless and classic look and offer a better grip, but wood is an unstable material that can crack, swell with humidity, harbor mold and bacteria and give you splinters.
Following centuries of tradition, KOTAI handles are round, wooden handles. But that is where tradition integrates modern technology to surpass itself: our handles are made of pakkawood, a composite material engineered by compressing wood with resin at very high pressure and temperature.
The result is a natural black pakkawood that will take a beautiful patina over the years while providing excellent grip (even with wet hands) and preventing water absorption, splinters and bacteria.
Another detail you may want to consider when choosing your knife is the handle bottom. Having a flat metal cap at the end of the handle will come in very handy when you need to crush garlic.
At the end of the day, knife selection is a matter of personal taste, cooking style and subjective preference.
Just keep those 5 criteria in mind to avoid disappointment and you will be one step closer to finding your ideal cooking partner.