Why would I prefer carbon steel (rust prone) kitchen knife?

Carbon steel is more malleable and less brittle than stainless steel. This means that it is easier to hone on a knife steel, to maintain an extremely sharp edge.

Some folks feel that the benefit of that sharp edge–for example, in easily slicing tomatoes, and other very fast prep tasks–is worth the compromise of more persnickety maintenance.

Lots of opinins but not much metallurgical knowledge.....reminds me of hotroders thinking something is better if its made out of billet instead 6061 AL (same thing). Where's that crazy smilie?

Carbon steel is actually a misnomer, in many industries carbond steel is refered to a mild steel alloy that isn't stailness. What our knives are made of is a medium to high carbon tool steel with a enough carbon that it can be hardened (all steels have some carbon). Stick with asking for carbon steel at the kitchen store or they won't know what you're talkning about, but thats the truth of it

Hardening means heating it past the critical tempurature (roughly red hot) and quenching it (differently mediums for different alloys, ie water, oil, air). After hardening, the steel is 'tempered' which means its reheated to a much low temp to 'let down' the steel or make it less brittle. This also reduces hardness, so the maker wants to create the right balance - different tools get different tempers depending whats expected from them - ie an impact tool is tempered at a higher temp to let it down more so it doesn't shatter. Left dead hard after a quench, the blade would be too brittle - it could shatter if dropped sort of thing.

Incidentally, this is what the japanese laminated cutting tools are all about - leave the inner tool steek very hard and use soft outer ducticle steel to give it strength.

Carbon steel knives were not created for sushi. They predate any stainless knife which is essentially a perfermance compromise - not has hard a steel (which IS edge holding ability) but the don't rust.

Carbon steel can be made extremely hard. even slightly harder than HSS (high speed steel) whose advantage is hardness at heat (up to red hot). This is an important foot note as grinding does expose the steel to very high temps - not all over but where the steel molecule meets the abrasive. Temps are high enough to effect the temper. This is why HSS is preferable for say a drill bit or even a chisel so it can ground and why you have to carefull with carbone steel if you're grinding so you don't wreck the temper

Anyway, maybe more than you wanted to know, but thats facts around the differences.

Carbon steel is, as you've mentioned, a lot harder to maintain than stainless steel. However, carbon steel is a harder metal than stainless steel, meaning that it will be less vulnerable to the physical stress of everyday use and will hold an edge longer than stainless steel. As such, carbon steel knives are generally regarded as better for heavy or extended use in busy kitchens, as the chefs won't have to stop and hone their blades quite as often throughout the day. Stainless steel knives, on the other hand, are much more resistant to staining and corrosion, but they are harder to sharpen and will require more frequent sharpening overall than carbon steel knives.

Each material has its pros and cons. In the end, you're really just trading one shortcoming for another—extra cleaning with carbon steel and extra sharpening with stainless steel—so the choice really just depends on what the knife will most often be used to do. If you frequently do a lot of hard chopping or slicing, investing in at least one quality carbon steel knife for heavy-duty applications may be a good idea. But if you're at home just cooking for your yourself or your family and will usually only need the knife for basic tasks and low-impact cuts, stainless steel will probably do just fine in most situations.

You can find more information on common knife materials in the following article:

http://www.jesrestaurantequipment.com/jesrestaurantequipmentblog/knife-guide-chefs-knives/

Hope that helps, and good luck with any future knife shopping!

Carbon steel is much cheaper than stainless steel although that isn't the only reason.

I have a a few of each I don't k ow much about the science behind the making of them but personally I find I can get a super sharp edge on my carbon steel knives in no time at all which they hold well where as it takes me longer to get a no where near as sharp edge on my stainless steel knives and they don't hold it as long. This however could simply be my sharpening skills. Overall I find carbon much sharper and a lot nicer to use and I would always choose them over stainless but if I'm in a hurry I use a stainless. Personal preference I guess but I would recommend trying a carbon I got a small paring one to start and was so impressed I decided to splash not on a chefs knife.

I have one of each - I do a lot of general prep work with my stainless but prefer the Carbon for dismembering cuts of meat. The sharper blade tends to cut through ligament and tendon easier.

The high carbon steel knifes are self sharpening as much as they are rust prone. You may have to sharpen it under heavy use but on gentle use on veggies you'll eventually get an edge that will last a decade or more. As the edge wears sharp, will the sides. A thinner blade will result. My mother has been using these types of knifes for 80 years.

Non-stainless alloys can be made with less (in percentage) alloying elements than stainless.

An alloyed steel is not a homogenous, amorphous mixture of whatever is stirred into the melting pot; things can form coarse or fine structures very much dependent on the specifics of the smelting, forging (or rolling), and heat treatment processes. The more admixtures, the more complex it gets to get it right. Unwanted coarse discontinuities, especially if they are not well attached and/or very hard and brittle or soft, make sharpening (or keeping an edge) precisely very hard because abrasives (or cutting medium) will have a different effect on these spots than on what is around them. At the same time, such spots in a controlled size can be welcome because they help stabilize the material. All a matter of balancing.

The thing is, inexpensive stainless steels used in medium-priced cutlery ($30-$150 price range) are commonly of a type that due to these limitations does not reach the hardness or fineness that just using carbon steel will afford you.

There are more modern semi-stainless/stainless steels considered equal or above carbon for culinary applications - these are, however, not often found in the medium price range - except the VG steels*, eg VG10, which are becoming more and more popular in that segment - but these are considered above (hard and robust) in some, below (not as hard or fine as the kind of carbon steel you would use for a sashimi knife) in other aspects. (To knife geeks: I'm referring to stuff like Silver-3, Niolox, or PM stainless, or SKD-anything-ish semi stainless at beginning of paragraph.)

Also, somebody producing carbon steel cutlery can usually assume that his customers will expect his wares being dishwasher- or snap-proof, so he has no reason to further limit hardness/use a more conservative grind/edge, trading in sharpness/edge retention for robustness.

*If you want to get a knife in VG steel, just look for any reputable but non-specialist retailer trying to sell you a damascus knife - chances are very high that you will end up with a VG steel knife.