Many of our queries regarding kitchen knives relate to materials, directly or indirectly.
Will the blade rust? How well can it hold its edge? How often do you have to sharpen the knife? — The questions carry on.
We overlook that understanding the material can provide us with a far better understanding. It affects everything from weight, maintenance, sharpness, edge retention, and much more.
That’s why we’ll dedicate today’s discussion to figuring out what kitchen knives are made of. We’ll discuss each material’s capabilities and shortcomings and help you figure out which one is suitable for what.
Materials Used to Manufacture Kitchen Knives
Let’s analyze each of the materials based on the making process, performance, and maintenance. This part will help you in figuring out which material outperforms which one.
Carbon Steel
Carbon steel has been the OG material for knives for as long as we remember.
Don’t all sorts of steel contain carbon, though?
Well, yes. The thing is, this material has a higher amount of carbon. Usually, that percentage revolves around 0.5% to 2.0% (it can go slightly higher or lower). It should technically be called high-carbon steel by default, but I’m not the one naming things.
The addition of carbon allows manufacturers to harden the steel more than usual. Otherwise, the steel would be softer, lowering its impressive sharpness.
Manufacturing
Carbon steel usually goes through two stages during manufacturing. The first stage heats the steel at extreme temperatures. The carbon allows it to be very tough in this stage but, in turn, makes it more brittle.
The second stage heats the steel again — but at a lower temperature this time. This stage is known as tempering. This stage lowers the hardness achieved through the first stage but also reduces the brittleness. This step is crucial to keep the knife from chipping too easily.
Even after the tempering process, carbon steel remains comparatively brittle. Dropping the knife and chipping its tip isn’t uncommon among users. Nevertheless, the superior hardness on the Rockwell scale allows these knives to be much sharper. This sharpness is essential for many, as it helps reduce friction and helps with intricate cuts.
Modern knives even utilize elements like Nitrogen to increase the hardness further, but we will delve deeper into that later.
Maintenance
A significant factor in carbon steel is its patina. This material reacts to some foods, forming a green and brownish layer over the blade. This phenomenon is known as patina and is the result of oxidation. Note that this is not the same as corrosion, so there’s no need to be worried.
That doesn’t mean you shouldn’t be worried about corrosion in general.
Carbon steel doesn’t have stainless properties, meaning you’ll have to be on your toes regarding maintenance. Not keeping the blade dry or not cleaning it in time can and will result in rusting.
Even with careful usage, it’s difficult to maintain a shiny blade. And that’s part of the charm for many, as it gives the knife a unique character.
These knives are comparatively easier to sharpen, fortunately. Even with constant usage, getting this material up to speed doesn’t take long. Although the edge retention isn’t the best out there, it’s nothing to frown upon, either.
Some of the popular carbon steel alternatives include 1055, 1095, AUS-8, or 440A. These steels have varied ratios of elements and different heat treatments.
Despite the shortcomings, most professionals still prefer carbon steel knives for the reasons mentioned. A sharp and consistent edge is crucial, especially if one uses knives regularly. Brands like Wüsthof, Zwilling, and Shun all have extensive lineups of carbon steel knives.
Stainless Steel
Now comes the fan favorite for many occasional users — stainless steel. The most significant property of these knives is their corrosion resistance.
Composition
Stainless steel contains a certain amount of carbon as well, but not as high as carbon steel. What gives it rust-resistant properties is chromium. In most cases, the steel has around 10-15% chromium to achieve that capability.
Too much chromium isn’t healthy, though — it can reduce the steel’s hardness.
Stainless steel knives also use a few other elements to increase their resistance to rust. Nickel and molybdenum play a crucial role in many variations of this steel. You’ll find many premium knives with those elements.
Stainless steel tends to be a bit softer in nature. This used to be a bigger issue, but modern heat treatment can do wonders. Now, it’s possible to find knives with impressive toughness on the HRC scale.
But it’s usually not as tough as high-carbon steel, which has pros and cons.
The Edge
The benefit of softer steel is lower brittleness. These knives have lower risks of chipping during heavy usage or accidental drops.
However, reduced toughness also means we can’t grind it as finely as carbon steel. Consequently, it usually doesn’t get as sharp as a high-carbon steel knife. And if you want a single-bevel knife for better sharpness, stainless steel isn’t the ideal option.
Maintenance
This steel doesn’t rust! That alone reduces the maintenance tasks. Users don’t have to worry about keeping it clean, wiping it every now and then, or sometimes even oiling it. It’s not impossible to make it rust, but it’s tough.
This material doesn’t get patinas either, so it retains a shiny and clean look.
Another benefit is edge retention. This material is more resistant to wear, meaning it will remain sharp for a decent while. The issue is with sharpening, though.
Sharpening stainless steel requires coarser sharpening tools. Tools like diamond sharpening stones are better suited for this steel. Even then, it takes more elbow grease than other steels. But for occasional users that don’t want to go through insane maintenance, it’s the better alternative.
Since it doesn’t react to ingredients, knives made with this material won’t affect the food’s taste, especially acidic ones.
This seemingly invincible nature doesn’t mean that users should use harsh or abrasive cleaners, as those can still affect the steel.
Pricing
While there are many premium stainless steel knives, there are also tons of budget options. Most of them are stamped knives, and the ease of manufacturing makes them more affordable than carbon steel products. That’s why this is the most popular material for users looking for something affordable.
Popular stainless steels for knife-making include the 420, 440, or 316. The 400 series is generally a bit tougher than the 300 series, although the series doesn’t automatically determine a knife’s quality.
High Carbon Stainless Steel
High-carbon stainless steel tries to combine the best characteristics of carbon and stainless steel.
This metal alloy contains a higher amount of carbon in it (compared to standard stainless steel). Modern powdered steels are good examples of that.
This introduces a few benefits, the biggest of which is the ease of touch-up. If you use your knife frequently, a higher carbon blade provides an effortless sharpening experience. And the chromium in the steel means the knife won’t rust easily.
Most of these knives will cost more, partly due to the quality and partly for marketing gimmicks. Even though brands boast about these knives being the absolute best at everything, that’s not the case. The benefits are certainly there but beware of the overselling.
Damascus Steel
Unlike high-carbon stainless steel, Damascus steel combines different steels and folds them together. Usually, the outer layers are comprised of steels higher on the HRC scale. In many cases, the carbon content is pretty high on these knives.
These knives are known for their toughness and unusual appearance. The appearance of the outer layer is unique and easy to manipulate, which is one of the reasons people love it.
The quality of these knives largely depends on the steel used to manufacture them. If those are sub-par, then the result won’t be awe-inspiring either.
Assuming a knife is made with quality Damascus steel, it can have impressive sharpness and edge retention. At the same time, it won’t rust as quickly as your usual carbon knives. That doesn’t mean that it won’t rust, though — it’s still far behind stainless steel in those terms.
Additionally, quality Damascus steel knives will cost significantly more than most alternatives.
Ceramic
Unlike the other options, ceramic knives are pretty new in the arena. The usage of ceramic allows blades to be extremely sharp. In addition, users don’t have to worry about rusting, as there’s no steel. These knives can also be surprisingly lightweight — which can be good and bad.
These can be very sharp because of their toughness, as the steel is heat treated at tremendously high temperatures. However, that makes these knives very brittle and prone to chipping.
Another issue is that sharpening these blades can be difficult. Usual methods like whetstones or sharpening rods won’t do for these knives, so there’s the added trouble there.
But considering the small maintenance requirements, these blades are becoming a consideration for many users.
My Last Two Cents on the Topic
As I said, knowing what kitchen knives are made of can get half the job done. It determines the weight, the sharpness, its retention, and everything in between. While there are some variations in manufacturing processes, those are the primary options you’ll come across.