One of the questions we get a lot is whether plain or serrated blades are best when shopping for a new knife. The physical differences are obvious, but the answer to which is better is considerably more complicated; it depends on what you'll be using the blade for, and in what situation.
Plain Edge — blades that are one continuous sharp edge — are far more traditional. They serve a much wider purpose as their most useful application is what most of us think of when we think of using a knife: a strong, steady pressure.
Another key advantage of a plain edge is that it doesn't snag or fray when cutting through some ropes, though with other ropes, particularly ones made of plastics or other synthetic materials, the blade may simply slip instead of cut. A plain edge cuts cleanly.
Serrated edges are blades that have some kind of toothed or saw-like edge ground into on the cutting surface. These are intended to be used much like a small saw, with a back and forth motion. They're great for cutting through belts and ropes, fabric, and various other textured materials. Serrated blades also work great on substances that are soft, flexible or can be crushed easily with downward cutting. A great example of materials that work well a serrated blade are: bread, cooked meats, soft fruits and vegetables.
The downside to the serrated blade, though, especially ropes and fabrics they can easily cause fraying, and when the blade dulls it's much more difficult to sharpen and requires specialty sharpening equipment. A serrated blade does not cut as cleanly as a plain edge knife. Often sharpening requires taking the blade to a professional sharpener, especially if the sharpening is long overdue.
Types of cutting
There is not just one type of cutting motion or one type of edge when it comes to knives. In fact, there are several different Types of cutting motions with knives, each of which are used with different knife edges.
First, there's push cutting. Push cutting is where a knife is used by applying force forward and pushing the knife edge in. An example of this is wood carving, or perhaps pushing a knife through a tomato. Push cutting works best with a plain non-serrated edge with a polished micro fine edge finish because the edge will be sharp and smooth enough to push right through. A micro fine or mirror polished edge can be obtained using an extremely fine abrasive sharpening system.
Slicing is using a knife in a back and forth motion, similar to a saw. This is commonly used for cutting bread, rope, or steak. Slicing uses a coarse micro edge or a serrated edge to cut. The serrations help the knife bite into the surface. The toothiness of the edge allows the knife to bit into the substrate.
Chopping is cutting with a single directional force. Usually, chopping happens in a downward motion to take advantage of gravity and acceleration. An example of chopping is cutting wood with an axe. Chopping requires a polished edge with a thickness that allows the knife to cut without chipping or failing. The knife needs to be thick enough and polished enough that it will chop through something thick, like wood, without breaking.
Push cutting, slicing, and chopping are three of the main cutting motions with knives. Each of these cutting motions require different types of edges. Next time you're chopping wood or just slicing your vegetables, think about what type of knife you are using.
The Right Blade for the Right Purpose
In the debate over plain vs. serrated knife blades, they key is picking the blade most suited for what you plan to cut. Generally, we'd say that plain edges work for most everyday use and carry. On the other hand, if you're into high adventure, whether that's a mariner, climber, hiker, or work as a chef or in the rescue or emergency medical field, a serrated blade would probably be a better fit.
If the knife will serve multiple purposes, there is a third option that should be considered: a combo serrated/plain edge blade. The mixed blade has a partially serrated portion at the base of the blade and at the end closer to the tip, plain. This provides less work area for each of the cutting edges, but allows you to tackle just about any cutting you may find yourself faced with.
So take a moment to consider what you'll be using your knife for, and if you can't narrow it down to one specific use, it will greatly help with your selection.