Stainless Steel Care for Beginners
With qualities that prevent it from rusting, stainless steel is highly regarded and often used in every facet of homebrewing — from stainless kettles with stainless immersion coolers, to hot liquor tanks, mash tuns and conical fermenters. While it is durable and rust-resistant thanks to a shield of chromium oxide, that doesn’t mean caring for your stainless steel equipment should be overlooked. Proper cleaning and care for your equipment will ensure these products last a long time, protecting what can be a hefty investment in homebrewing equipment and preventing contamination. While a long brew day can sometimes leave you short on motivation to clean up, do not put it off!
Corrosion, particularly around scratches, can occur below stuck-on grime when there is no free oxygen to maintain the passive chromium layer. If those brownish or whitish spots on the bottom of your brew kettle aren’t removed they may cause pitting underneath them. Stainless steel can be cleaned using most household cleaning items, with one major exception: chlorine bleach. Chloride ions present in bleach attack stainless steel and have the strength to break down the invisible chromium surface on your stainless steel. Bleach is incorporated into many common household cleaners, so be sure to read what is in the cleaning products you use before you begin cleaning your stainless.
Ordinary household soaps and detergents work great for cleaning stainless, but if there is a heavy-duty scrubbing that needs to be done (ever burn extract to the bottom of your kettle?), common cleaners like Bar Keeper’s Friend and Powder Brewery Wash (PBW) can remove most grime with the assistance of a woven nylon scrubber or dish brush. Do not use steel wool, as it will leave tiny steel particles embedded in the surface and, over time, those pieces will rust! Once surface rust has breached the protective chromium layer, the iron in your stainless product will begin to rust as well. If this happens, rust stains can be removed with Bar Keeper’s Friend or using a solution of nitric acid and water (about 1 part nitric acid to 10 parts water), letting it sit for up to an hour and then washing it off. After cleaning, always make sure to carefully rinse your stainless to ensure no cleaning products dry on the surface.
Stainless steel is not scratch proof. While light surface scratches should not be a problem, deeper scratches (ones you can feel) should be buffed or grinded out because they can lead to crevice corrosion. Again, the rust that may form in these scratches will spread due to the iron in the stainless steel. You can buy an abrasive intended for use on stainless steel from welding supply stores to smooth out scratches.
After smoothing, clean the area well with kitchen cleaner to give it a good polish. Air contact will naturally strengthen the chromium over the buffed area so your equipment will remain rust-resistant.
