Identifying the Best Knife: Carbon Steel vs Stainless Steel

All steel has carbon, otherwise it wouldn’t be steel – and the amount of carbon in the steel (amongst many other factors) determines its hardenability. All steel also contains manganese, but that is for reasons of initial forming rather than its working properties further down the line.

Furthermore, steels can be categorised in lots of different ways; by their carbon content or by the number of additions to the alloy – from nitrogen to vanadium via many points of esoterica in between.

What is carbon steel?

True “carbon steel” is where almost nothing has been added to the iron aside from carbon and manganese, with very often a pinch of silicon for knife steels. Beyond this we move into the realm of low-alloyed steel and then up into the peaks of the high-alloyed. The demarcation between the two isn’t entirely clear, but if we took going below 95% iron content as the line after which we’re high-alloyed then that will do for our purposes.

The point here is that stainless steel is just a subset of high-alloyed steel, with the addition of at least 10% chrome – but more often around 15%.

Without getting into the whole thing about what makes a good steel, it’s fair to say that badly made, cheap stainless steel makes a worse knife than its low-alloyed or carbon brethren.

But since we’re all discerning people who don’t want to bottom-feed, that doesn’t concern us. At the other end of the spectrum, at the high end, given that we control all the other factors that influence the quality of a knife to be the same, there is no real functional difference between a stainless and non-stainless steel.

Does stainless steel rust?

The one handy differentiator between stainless and non-stainless steels is that the former does not rust.

Ah-ha! The dreaded ‘rust’ word – more often called a ‘patina’ by those trying to turn a bug into a feature. Aside from making a hell of a mess of lettuce and needing to be kept an eye on, it’s not the end of the world for the most part and we can (if we squint) see the appeal of a knife that ages and matures as you use it. But as with so many things to do with knives, nothing really matters as much as the cutting edge, and it’s here that stainless gets a small lead.

The metal at your cutting edge is at its thinnest and most exposed, and if you don’t have a corrosion-resistant steel then you’d better keep that little bit very clean. Just leaving lemon juice on the edge of the blade for 30 minutes will see it degrade significantly in comparison to its stainless compatriot.

Carbon steel is used by makers for whom the material is most apt – generally those who forge by hand or are maintaining a tradition. The annoyance lies – from our perspective – with the perpetuation of the myth that stainless steel is somehow inferior, when one could very cogently argue that the opposite is true and that the whole discussion only rumbles on because of misinformation and the whole 5 Monkeys problem.

At Savernake we put extensive research and hours of testing into the steel we use for our blades. We now almost exclusively use Swedish Sandvik 14c28n, although on occasion we use RWL 34 powdered metallurgical steel and other exotics. In tests conducted by the Cutlery and Allied Trades Research Association, Savernake blades scored in the top 2.5% of knives tested and were rated ‘excellent’ for sharpness and durability. Browse all Savernake knives or create your own custom knife. The Savernake team are always on hand to answer any questions you have. Email hello@savernakeknives.co.uk or call +44 (0) 1672 870120.