Straight to the Point
I've been quietly in love with carbon-steel knives for a long time, and after a lot of thought, I've decided that it's time to share it with the world. The carbon-steel knife you see pictured above? Well, I'd like to introduce you to the love of my knife. Yup, that's my baby right there.
If you're curious, it's an 8-inch Misono carbon-steel Gyutou. It's my favorite knife, but as Kenji has written before, a knife is a very personal choice. What feels right in my hand may not feel right in yours. Our chef-knife buying guide is a good place to explore your many options.
For a long time, I lived in denial of how strong my feelings were. People would ask me what knives they should buy, and, unless they were professionals, I'd always steer them towards stainless steel. I figured I was giving good advice, since stainless steel is more forgiving, and most home cooks are looking for ease.
But now I'm going to tell you what I really think: if you take cooking seriously, if you're ready to invest a little bit of time and a lot more care, and—this is a big one—if you're willing to sharpen your own knives, then carbon steel is where it's at. It pays off in dividends.
If you just want to get dinner on the table, not think about your knives beyond whether they're just barely sharp enough to blunder their way through an onion, and not worry if you mistreat them to no end, then yeah, stick with stainless.
The Beauty of Carbon Steel
I'm not an expert when it comes to the finer points of metallurgy, but for our purposes, what's important to know is that the difference between carbon steel and stainless steel is that stainless has chromium added to carbon steel's basic iron-and-carbon mix. The chromium bestows upon stainless its resistance to corrosion and rust.
That rust resistance of stainless, though, comes at a price. First, stainless tends to be a softer form of steel, which means it often won't hold an edge as well as carbon steel. That's right: carbon steel stays sharper longer than stainless.
Second, and this is really important, carbon steel, despite being harder than stainless steel, is way easier to sharpen than stainless.* This is critical because, in my experience, knives that are used frequently simply don't stay very sharp for long. Sure, they stay sharp enough to do their job reasonably well, and certainly sharp enough to cut you if you slip, but not high-performance, precision sharp.
*I'm guessing this is where the metal experts out there say I'm wrong, and that there are all sorts of stainless-steel alloys that are harder than carbon steel, or easier to sharpen than carbon steel, etc., etc. That may be—I know I'm generalizing here—but of all the kitchen knives I've ever worked with, carbon steel knives sharpen way more easily.
Having knives sharpened once a year is a very good thing to do, but it's also the bare minimum. In just a few weeks of moderate use, those freshly sharpened blades lose their gleam and the onion you're trying to dice goes from feeling like air to feeling like an actual object with enough substance to offer at least minimal resistance.
I want an onion that feels like air, and that requires more frequent sharpening. And if I'm going to sharpen my knives more often, I definitely want a knife that I can give a razor's edge to with as little effort as possible. And there's only one kind of knife I've ever used that makes sharpening so easy. Carbon steel.
A little anecdote on just how sharp I can get my carbon steel: my knife once cut its way through my knife bag—a bag that's designed to contain sharp knives—while I was on the subway. I wondered why everyone was staring at me until I noticed the blood dripping from my finger. Which means it's also sharp enough to cut you without you feeling it.
The Problem With Carbon Steel (Hint: It's Not a Problem)
So here's the downside: carbon steel is more fragile. It's a more brittle material, which means it's more likely to chip if you drop it or toss it into the dishwasher. It also rusts and stains easily. With prolonged exposure, it can also react with certain foods like onion, darkening them.
For a long time, I thought of these negatives as being a significant reason not to recommend carbon steel to most people. But the more I've thought about it, the more I've changed my mind. I actually think carbon steel's reactivity is a great thing. Why? Because it forces the cook to treat the blade with some real damn respect.
I'll be the first to admit it: with my stainless steel knives, I can be a little careless sometimes. Their built-in low-maintenance makes it too easy to mistreat them. With my stainless steel knives, it's not uncommon for me to put a dirty one in the sink with the intention of washing it just a little later, only to leave it there as plates and bowls pile up around it, potentially dinging the blade.
If I splash my stainless steel knives, or use them to cut something moist, sometimes I'll let that moisture and food residue sit on the blade for several minutes before I wash it off. Sometimes it dries on before I get to it.
Not my carbon steel, no way. I handle my carbon steel blade like a samurai treats his sword. It's all reverence and care, one hundred percent of the time, because the knife demands it. Use the knife, clean the knife, dry the knife, repeat. Sit it in the sink? Not for one nanosecond. When I'm done, I rub the blade with mineral oil to form a protective coating that prevents rusting in storage.
In the end, this can only be a good thing. A knife is a cook's single most important tool. It should be treated with care. Carbon steel won't let you get lazy, because it insists on being treated right. It's a self-respecting metal like that. In return, it gives you one of the sharpest, hardest edges you could ever hope for.
And, because of its tendency to stain, in time it becomes more and more yours. Like good leather shoes, raw denim, and a favorite baseball cap, carbon steel only gets better with time, developing a patina that tells the story of how it's been used. That's a truly beautiful thing.
The Criteria: What to Look for in a Carbon Steel Knife
There are two key elements to keep in mind when it comes to choosing a quality carbon steel knife: sharpness and hardness.
Carbon steel can be incredibly sharp, but how well does the blade retain its finely honed edge? Some home cooks are happy to sharpen their blade before every use, while others are lucky to remember to have their knives professionally serviced on an annual basis. A quality carbon steel knife will maintain its sharpness long after it leaves the whetstone. And, while renowned for its strength and durability, carbon steel can also be brittle. A good carbon steel knife will have a strong, hard blade that isn’t prone to chipping or breaking under proper use.
What’s the difference between carbon steel and stainless steel knives?
As the name suggests, carbon steel is high in carbon. This means that carbon steel knives are ultra-strong and capable of achieving razor-sharp edges, but they’re more susceptible to corrosion and rust. Stainless steel knives, on the other hand, contain chromium—an element that helps protect against corrosion and rusting.
While carbon steel knives are technically stronger and sharper than stainless steel knives, but require more care (as they will rust if not treated properly).
How often should you oil carbon steel knives?
Ideally, carbon steel knives should be oiled after every use. A few drops of food-grade mineral oil rubbed into a clean, dry blade will protect against moisture damage while keeping the steel shiny and smooth. At a minimum, though, carbon steel blades should be oiled weekly until a natural patina develops.
How do you prevent carbon steel knives from rusting?
Washing and thoroughly drying carbon steel knives directly after use is the best way to protect against rust. This does not mean giving the knife a cursory wipe across the nearest dish towel—take care to completely dry the blade with a clean, absorbent cloth.
Regularly treat carbon steel knives with mineral oil and store in a dry location. And never, ever, put one in the dishwasher.