Why can stainless steel knives still rust?

As discussed in previous articles: stainless steel is about making the best compromise for the application. Some knives will rust right before your eyes, and others can survive in saline conditions without oxidizing. Not to worry, keeping your knives rust free is a breeze.

Rust resistance is a part of the chemical balancing act when designing a steel alloy. In kitchen knives sharpness plays a big role too obviously. Sharper is better. Some knifemakers take this to the extreme and will readily sacrifice rust resistance for a harder and sharper blade.

ABOUT CARBON AND CHROMIUM

The primary element in most alloys that increased a steel’s susceptibility to rust is carbon. The more carbon, the easier the alloy will oxidize. More carbon also means a steel that can be tempered to be harder.

To compensate for this chromium is added. The more chromium, the more rust resistant a steel is. However, chromium also decreases the steel’s ability to take and hold a sharp edge. So too much can be a bad thing.

The steel we use at BARE Cookware is very rust resistant. We’ve struck a balance between hardness and rust resistance. Our steel is hardened to 58 HRC while remaining rust resistant. But just like any steel can rust if subjected to certain conditions. Let’s take a look at risk factors for rust forming.

ACID, SALT, MOISTURE, HEAT

Acid, salt, and moisture will all act as a catalyst and speed up oxidization. Acid can reach kitchen knives in numerous ways. Think fruit-juice, vinegar, and even the moisture that naturally occurs on your skin. Salt is used in just about every dish, moisture is as abundant in a kitchen as is heat.

A special mention should be made about sea-air. In coastal regions the air is both humid and high in minerals (salty). Extra care should be taken to store knives in a dry area.

HOW TO CLEAN RUST

Eventually rust can form on any steel, even stainless steel. So how to keep your knife gorgeous and rust free? It is important to scrub off any surface discoloration before the oxidation starts to eat into the steel. We advise to do this with a scrubbing sponge and some dishwashing detergent. If that is not strong enough a piece of steel wool can be used.

Only when the rust is more developed would we ever want to break out the big guns. Think fine grit sandpaper and brake cleaner. It should be clear that this is always to be avoided. That brings us to our most important point to keep your knives rust free.

HOW TO PREVENT RUST

Luckily preventing rust is a simple 3 step routine:

1. Clean the blade by hand after every use. A quick rinse will usually suffice.

2. Dry the blade before storing it.

3. Never ever put a high-quality knife in the dishwasher.

Do not postpone this. Do not leave your kitchen knives lying around dirty. It is unsafe, unhygienic and promotes oxidation. After years of following this simple habit we've yet to see any rust on the BARE Knives we personally use. Interested in more knife care? Here you go!