Most chefs who cook a lot of meat (especially fish) will likely already be familiar with fillet and boning knives, but those who do not spend their days carefully preparing fine cuts of meat may not have much exposure to this type of blade. These smaller kitchen knives are used to debone and break down fish, poultry, and other cuts of meat, and they feature a variety of distinctive qualities that make them perfect for the job. Although boning and filet knives are often used interchangeably, there are some important differences between the two.
As mentioned, boning and fillet knives are ideal for use when working with meats (and certain types of vegetables) that call for precise, careful cuts during preparation. Most commonly, boning/fillet knives are used when cleaning and preparing fish, as they are well equipped for working around and removing small, soft fish bones. The blades of boning and fillet knives are made significantly thinner than most other kitchen knives to allow the blade to flex. This flexibility allows the blade to bend slightly and “conform” to the surface of what you are cutting, making fillet knives ideal for removing the skin from flat cuts of meat.
Typically, fillet knives are always designed to be flexible. While some boning knives are flexible, they are not all necessarily designed to be so. Non-flexible boning knives are well-equipped for cutting tougher meats like pork or beef, as the thin but sturdy blade allows for higher precision cuts than a standard chef’s knife. The flexible blades of fillet knives—while perfect for soft meats like fish and chicken—offer less strength and overall stability when cutting tougher meats, and they can quickly go dull if used in more “heavy-duty” applications. While boning knives can usually be used in the place of a fillet knife, it is not always the case that the opposite is true: a thin fillet knife that is used too frequently on tough or difficult cuts of meat may be in danger of warping over time.
Most boning knives feature straight blades with pointed tips that facilitate the precise removal of bones and other unwanted portions of meat, especially in deep cuts and crevices. Common fillet knives also feature a similarly long, straight shape, although some fillet knives curve upward toward the end of the blade to improve their capability for removing skin from fish in a single pass cut. These curved blades are generally reserved for use with flat cuts of fish, as the curved tip—while ideal for making long, steady cuts—inhibits the overall maneuverability and practicality of the knife in other situations.
Much like any other knife, the overall quality of your blade will be determined by the same three factors governing chef’s knives: forged vs. stamped, full tang vs. partial tang, and material. Like chef’s knives, boning and fillet knives are available with either forged or stamped blades, as well as full tang or partial tang handles. Forged, full tang knives are generally recommended when purchasing a reliable chef’s knife, but the distinctions are not quite as critical when shopping for your next fillet knife as they are when choosing an all-purpose kitchen knife. Because boning and fillet knives are used for precision cuts and careful deboning, they are generally not subjected to the same levels of stress as other types of kitchen knives, and therefore do not necessarily need to be quite as robust as the rest of your cutlery. Many professional chefs and fishmongers use stamped blade, partial tang fillet knives without issue.
Material, however, is still just as important as ever. High-carbon steel is generally the preferred material for the thin blades of boning and fillet knives. As discussed in our previous knife guide posts, stainless steel is very easy to clean, but it does not hold an edge as long as carbon steel. This is an especially problematic trade-off with fillet knives, as the thin blades already tend to lose their edge faster than larger, thicker knives. Although they require more care to prevent rust and corrosion, high-carbon steel blades will maintain their edge significantly longer than stainless steel. High-carbon steel is also easier to sharpen than stainless steel, making the inevitable trips back to the sharpening stone a less time-consuming task.
Most chefs (both amateur and professional) will probably want to keep at least one boning knife and one fillet knife in their cutlery collection. Some prefer to invest in a single, multi-purpose filet/boning knife, but having a thin, flexible fillet knife and a solid, maneuverable boning knife on hand should keep you well equipped to clean and prepare any kind of meat or fish.