Salt pitting: the one thing that will genuinely damage your steel
Stainless steel shrugs off acid, heat and abrasion. Chlorides are the exception, and the damage they do is permanent.
We have said several times on this site that stainless steel is remarkably tolerant. It is. But there is one failure mode that is real, permanent, and entirely avoidable, and it is worth understanding properly.
What pitting is
Pitting is localised corrosion. Instead of a surface corroding evenly, the attack concentrates in tiny spots and drills downward, producing small deep craters.
It is more serious than surface staining because:
- It is permanent. Metal is gone; no cleaning restores it.
- It creates crevices that hold food residue and are hard to clean.
- Over time, deep pits can perforate a thin wall.
Why chlorides do it
The chromium oxide passive layer is stable against most things food throws at it. Chloride ions are the exception — they penetrate the layer at weak points and prevent it re-forming there.
Once a spot has lost its protection while everything around it is still protected, an electrochemical cell is set up: the tiny unprotected area becomes anodic and corrodes rapidly, while the surrounding surface stays fine. The attack focuses and drives down.
The three situations that cause it
Undissolved salt on a hot dry surface
The classic. Salt thrown into a hot empty pan sits as solid crystals on hot metal — high chloride concentration, high temperature, no dilution. This is the single most common cause.
Instead: add salt to liquid that is already in the pan and moving.
Brine or salted water left standing
Salted water left in a vessel overnight, or a marinade left for a day, gives chlorides prolonged contact.
Instead: empty, rinse and dry after salty preparations. Do not use a cooking vessel as a long-term brine container.
Chlorine-based cleaners
Bleach is a chloride source. Left in contact — especially overnight, especially at strength — it pits steel.
Instead: hot water and detergent for cleaning; a sanitiser rated for stainless steel if you need one.
Spotting it early
Pitting starts as tiny dark specks that do not wipe away and feel very slightly rough. If you catch it at this stage, clean thoroughly and passivate, and the surrounding surface will be protected even though the existing pits remain.
If a vessel is badly pitted
There is no repair. Assess it honestly: shallow scattered pitting on the outside is cosmetic; pitting on a food-contact surface is a hygiene issue, because pits harbour residue that cannot be cleaned out. A food-contact surface with significant pitting should be retired.
The short rule
Salt into moving liquid. Never store brine. Never use bleach.
Three habits, and pitting never happens.
Specifying cookware for your kitchen?
Every product on this site publishes its full size chart — gauge, dimensions and weight for every size. If you would rather just describe the job, we will tell you what to order.
