In addition, you probably don’t want these oils and compounds in your beer. As a result it may have oils, buffing compounds, welding compounds and other contaminants that are protecting the steel, but could be washed away the first time you clean your parts. Now some stainless brewing equipment, particularly lower cost stainless components, may have been machined, stamped, etched, buffed or welded after the stainless steel was manufactured and acid washed. Passivation happens very quickly – usually within 20 minutes. The acid also exposes the chromium to oxygen in the air, which activates a process called passivation where the oxygen bonds with the chromium to form a protective chromium oxide layer. When stainless steel is produced it is typically dipped into a bath of nitric acid near the end of the manufacturing process to remove contaminants. Stainless G2 Kettle Passivating Stainless Steel to Protect It Don’t stack regular steel pots, mixed metal tools or equipment in your stainless pot after brewing. The iron from regular steel tends to rub off onto the stainless steel (iron-affinity) and erode the oxide layer. In general you should keep regular steel such as that used in common cans, tools and some equipment away from your stainless equipment. Excessive scouring, particularly with steel wool can also erode your oxide layer. Bleach products can remove the protective layer. However if you expose it to bleach or other bleach-cleansers, scratch it, scour it excessively, or expose it to non-stainless steel scouring pads (such as steel wool) or leave it in contact with plain steel it can wear off the protective layer. Your stainless brewing equipment is generally very corrosion resistant. However if the chromium layer gets breached for some reason, then the iron in the steel may actually start to corrode and rust. This chromium oxide prevents rust and corrosion. The chromium in stainless steel reacts very quickly with oxygen and actually forms a protective layer of chromium oxide on the surface of the steel. Chromium is as much as 10-30% of the steel composition, and it is the critical element that makes stainless steel corrosion resistant.

In contrast, stainless steel is made from iron and chromium.

Steel is made from a combination of iron and carbon, and the carbon makes up only a half percent or so of the steel. So this week we take a look at how and why stainless steel can corrode as well as how you can passivate your stainless steel beer brewing equipment to protect it. Despite its reputation as the perfect metal for beer brewing, stainless steel can actually corrode or rust.

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