The better the steel alloy used, the longer the knife will stay sharp and the easier it will be to re-sharpen. The performance of a blade is also dictated by how the steel is hardened and tempered. Kitchen knives are typically made up of four types of alloys.
- CARBON: Allows steel to be tempered harder and sharpened to a keener edge.
- CHROMIUM: Provides steel with corrosion resistance. The higher the Chromium content, the greater the resistance to rusting and staining.
- MOLYBDENUM: Adds toughness and strength and gives steel the ability to hold its edge.
- VANADIUM: Gives steel resistance to wear while also providing resilience and flexibility.
Most people believe there are only two types of steel: carbon steel and stainless steel. For many years, carbon steel was believed to be the best material to use for a knife because it held its edge well, sharpened easily, and offered both toughness and resiliency. Because of the poor quality of the first few generations of stainless steel knives, many people still believe this today and will only ask for carbon steel knives. However, only a handful of today's manufacturers are able to produce pure carbon steel blades. Most choose to produce a high carbon stainless steel combination that is just as good as, if not better than pure carbon steel. This shift is a response to the demands of today's maintenance-free world where people want both the durability and cutting power of quality carbon steel and the stain and rust resistance of good stainless steel. We use four criteria to rate the type of steel used in a modern knife:
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Edge retention - How long it will hold an edge.
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Corrosion resistance - How well it can resists staining and rusting.
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Ease of Sharpening - How easy it is to keep sharp and to re-sharpen.
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Toughness & Durability - How long the knife will last.
A properly balanced and weighted knife will do most of the work for you because you won't need to apply as much pressure while cutting. This will also significantly reduce hand fatigue. Here are the basic parts of a common kitchen knife:
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The BOLSTER is usually the bridge between the handle and the blade. The bolster adds weight and balance to a knife while protecting the hand like a guard. On a Chef's knife, it is usually the balancing point of the knife. |
The TANG is the part of the steel that extends from the blade into the handle of the knife. A full tang extends all the way through to the end of the handle, adding weight, balance and a feeling of solidity and heft. |
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The BLADE is the main cutting portion of the knife. Blades can be made from stamped, forged, laser cut, or folded steel. |
The HANDLE is made from a variety of materials and shapes. Choosing one that is comfortable in your hand and durable enough to last many years is vital to a lasting relationship with your knife. Although nothing beats the beauty and feel of quality wood handles, synthetic handles are more stain resistant and durable. |
Knives are usually constructed using one of these methods:
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STAMPING - This common and inexpensive method involves stamping the blade from a sheet of steel of uniform thickness using a die (mold). The effect is similar to using a cookie cutter on dough. Stamped blades can sometimes be weaker because of the fatigue the stamping process puts on the steel.
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TRADITIONAL HOT DROP FORGING - A fully forged knife begins and ends as one complete piece of steel. Dropping a large forging hammer weighing several tons on the red-hot steel molds the knife into shape. The biggest benefit of forging is that the steel will have a finer grain to it, thereby improving the edge retention and quality of edge when re-sharpening. There are very few manufacturers today who use traditional forging as a method.
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PRECISION FORGING - The ultimate combination of old world craftsmanship with new age technology. A single bar of steel is heated to 1,092 C (2,000˚F) while being simultaneously compressed to shape the blade and form the distinctive raised bolster. Precision forging results in a finer grained steel without the carbon "flaws" inherent in traditional forging.
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LASER CUTTING - Blade designs are programmed into a computer and cut from a single thickness of steel using a laser beam. To enable laser cutting, only the finest grained steel can be used which ensures superior edge retention for the blade.
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FOLDED STEEL - Some Japanese-style blades are made by folding and hammering multiple layers of stainless steel around a super-hard high carbon steel core. A folded steel blade can offer superior sharpness and edge retention, but can be very difficult to re-sharpen when it loses its edge.
When considering a knife, the most important feature is the size, shape, and design of the blade. Each blade is designed for a specific purpose. A thin blade, for example, will make finer cuts, but can also dull or chip faster when compared to a thicker blade. In addition to the blade design, the knife's cutting ability will depend on the type of cutting edge used. Most knives use one of four different cutting edges:
PLAIN EDGE: Provides superior performance and ease of use for all foods when chopping, mincing, slicing, or dicing. This type of edge requires regular maintenance but can be re-sharpened over and over again for many years of service.
SERRATED / SCALLOPPED EDGE: Serrated edges are often found on higher quality bread, tomato, or some carving knives. The sharp teeth quickly break through the hard outer crust of breads or the tough skins of tomatoes, while the scallops do the actual cutting. A serrated edged knife will not cut as cleanly as a plain edged knife and cannot be used for dicing or chopping. A good quality serrated edge can be re-sharpened. 
FLUTED / GRANTON EDGE: Designed for slicing meats, fruits, and vegetables, the Granton edge creates an air pocket between the blade and the food being cut allowing the food to fall away from the knife with less sticking to the blade. This edge can be maintained and re-sharpened like a plain edged knife.
SAWTOOTH EDGE: This type of edge cuts best when simulating a sawing motion. Saw toothed edges stay sharper than plain or scalloped edges because the teeth do the cutting. Unfortunately, this edge is unsuitable for raw meats, fish and other soft textured foods as it tends to tear food. Once dull, most saw toothed edges cannot be re-sharpened again. 
