Picking The Right Fillet Knife to Process Your Catch

You may think you’ve got every piece of fishing gear known to man. But if you don’t have a fillet knife, you’re missing a major piece of the puzzle. Picking the perfect tool to clean and prepare your catches can be a headache. There are lots of different brands, materials, designs, and sizes. Where do you even start? 

That’s why we put together a guide to give you all the resources you need to find the ultimate fish filleting tool. Let’s dig in! 

Why Do I Need a Fillet Knife?

If you’re the type of angler that cleans their catch with a pocket knife and then wraps it in tinfoil to cook it, you’re probably wondering why you’d even want a special knife. There are a couple of reasons you might want a fillet knife. For one, they can do the same jobs as your old folding knife, just more easily. If you plan to prepare lots of fish, a fillet knife is more than helpful. Many anglers would consider it a necessity. 

To be more specific, fillet knives are all about precision. Every part of their design makes them ideal for processing meat quickly and easily. For fish, this means not just gutting, but also boning and removing scales. If you haven’t ever used a fillet knife to do these jobs, trust us. It makes a whole world of difference. More than just that, fillet knives are meant to stand up to lots of abuse for a long time. So if you’re a fan of objects that you only have to buy once (like, once in your lifetime), you won’t regret this purchase. 

This is really just the tip of the iceberg, though. Fillet knives are for a lot more than just processing fish. They excel at any sort of meat processing you might need to do. From cutting paper thin slices of roast beef for cold cuts to butterflying chicken breasts, your fillet knife is your new best friend. You can even use them to process big game, if you’re the type to do it all at home. If you fancy yourself a home chef, you won’t feel complete without a high-quality fillet knife. 

Properties a Fillet Knife Should Have

So now we know what a fillet knife does. Let’s explore how it does what it does. Fillet knives have a few features that help them to be more precision oriented and stand up to lots of wear. 

The Shape

Fillet knives are usually designed to be long, slender, and thin. This makes them flexible and easy to work with at different angles. A flexible knife allows you to work around bone and cartilage, a huge plus when separating the meat from the other bits of the animal. 

Part of what accomplishes this flexibility is what’s called a “distal taper.” This means the blade is thicker toward the handle and thinner toward the point. Distal tapering makes the knife more flexible while keeping it strong. We’re looking for something that flexes, but doesn’t bend. So when the tension is released on the blade, it returns to its normal straight shape. Distal taper makes this possible. 

Fillet knives also have a curved blade, with a reverse-curved spine. This shape is also called a “trailing point” or “recurve blade”. This means the unsharpened side angles up, maximizing the length of the cutting edge or “belly”. When using a fillet knife, you pull the knife forward as you cut rather than chopping like you would with a kitchen knife. Having more cutting edge means you can get through more meat with each slice. 

The Cutting Edge

It almost goes without saying that a fillet knife would have to be pretty sharp, and they are. This is accomplished a few ways. First is having a very low bevel angle. The bevel angle of a knife refers to the width of the “wedge” shape leading up to the cutting edge. Most Fillet knives typically have a 12-17 degree bevel angle, one of the lowest among different knives used in the kitchen. This means the metal of the knife is much thinner at the cutting edge than most knives.

Fillet knives also use different types of bevels, or “grinds” than other knives and tools. For example, kitchen knives usually have a flat double bevel, or “V-edge” (more typical with German knives) or single bevel, or “chisel edge” (Japanese knives). These bevels are useful for holding an edge and doing a wide variety of tasks. Axe blades are rounded, or convex. This gives them maximum durability. On the other end of the spectrum, skinning knives typically have a “hollow edge,” which is concave on both sides. This creates the sharpest possible edge. 

Fillet knives are one step back from skinning knives in terms of sharpness. They usually have a double bevel, with a different curve on each side. Some are flat on one side and convex on the other, where others are flat on one side and concave on the other. These shapes do two things. First, they create a balance between sharpness and durability. And second, they add a level of customization to the knife. High-end fillet knives are usually either right- or left-handed, depending on how the edge is beveled. Remember, fillet knives are meant to withstand heavy use. And having the maximum comfort and ease of use is important with tools you plan to use all the time. 

The Handle

This point is a great segue into our next feature: the handle. Because fillet knives are often covered in blood or water when we’re using them, the handle needs to do two jobs. It needs to be comfortable, and grippy. We’ll get into this more when talking about materials. For now, suffice it to say that we’re looking for something that won’t go flying out of your hand when it’s covered in slime and river water. 

Best Materials For a Fillet Knife

Different knives are made of different things. Who knew? However, there isn’t necessarily a “right” and “wrong” answer for what to make a fillet knife out of. And as it turns out, most knives are built differently. 

The Blade

Simply put, a fillet knife should have a blade made of high carbon steel. What you may not have known is that there are about a thousand types of steel, and each of them behaves slightly differently. On top of that, there is the almighty “cost” factor. If there is one thing that separates a $20 knife from a $150 knife, it’s the quality of the steel in the blade. 

Before we get to examples, let’s define what it is we’re after in good steel. Ideally, we want a fillet knife that’s flexible, strong, sharp, holds an edge forever, and is resistant to corrosion. Corrosion resistance is important any time we’re working around saltwater, which we probably will be. Now, it should be stated that finding a knife that does all of this to a T is almost impossible. But we can get pretty close. 

On the high end ($75-150 range), you typically see knives that use either S30V, S90V, or S110V steel. S30V is probably the best all-around steel, with good corrosion resistance, toughness, and edge retention while also being fairly easy to sharpen. S90V and S110V excel in edge retention, and are commonly found in the most high-end knives. 

Knives of middling cost ($30-75 range) use a wide variety of steel types. Two you may see are 7CR17MoV and 12C27. These do well all-around at holding an edge, corrosion resistance, and strength, though not as well as those mentioned above. For most of us (that is, those who aren’t professional chefs or butchers), this quality of steel is totally fine. It’s high carbon and will get the job done very well. 

Cheaper knives ($20-30 range) commonly don’t list the type of steel they’re made of, or simply say “stainless steel”. This is vague, and can make it harder to compare knives individually. But stainless usually has good corrosion resistance, which is good. If you’re buying your first fillet knife or something you don’t need to worry about as much (for example, to take camping), this is a reasonable option. 

The Handle

Now back to handles. Handles are often made of wood, rubber, or plastic. Wood is the best for comfort, but can be slippery when wet. If it isn’t finished properly, wood can also absorb and hold onto smells. This is why we tend to see wood handles on both low-end and high-end knives. Rubber and plastic sacrifice a little bit of comfort for fantastic grip. In general, a synthetic or rubber handle will outperform a wood handle. Most of all if you have to process lots of fish at once.

Picking a Knife Based on Your Needs

Now that we’ve explored all the minutia that makes a good fillet knife good, we need to think about how to pick the right knife. Consider your budget, and what you plan to use the knife for. If you’re primarily boning and cleaning trout and bass, a 6” knife will work perfectly. For larger fish and other large cuts of meat, a 10-12” knife will help a ton. Some fillet knives come in sets of two, one large and one small. This covers your bases size-wise without breaking the bank. Lastly, if you want something to take backpacking, you’ll want a nice sheath to put it in. Protecting the edge you just spent all that money on is key. If you treat it right, your new fillet knife will outlive you! 

Conrad Lucas is a biologist, naturalist, and writer from Salt Lake City, UT. He specializes in bat ecology, and loves skiing, caving, canyoneering, climbing and fishing. You can follow him on IG @drinkfluoride and find his creative work at www.jconradlucas.com

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