Stainless steel is widely used in commercial kitchens because it’s durable, foodsafe and easy to clean. Improper maintenance however, can damage the stainless steel’s surface, resulting in corrosion. Fortunately preventing this is simple.
Why does stainless steel corrode?
Stainless steel is a passive metal as it doesn’t actively corrode in the natural environment. This is due to stainless steel containing additives such as chromium or nickel. These additional metals form an invisible film protecting against corrosion.
When this film is damaged the stainless steel finish will start to degrade. There are three main reasons that the protective layer can become damaged.
- Mechanical Abrasion such as steel wool, wire brushes or metal scrapers.
- Water and food deposits left sitting on the surface will leave water spots and can break down the protective layer.
- Chlorides found in water, food, table salt and many household and industrial cleaners.
Safe Cleaning of Stainless Steel
Regular maintenance of your equipment is one of the easiest ways to ensure it remains in the best condition.
By quickly cleaning up spills and with regular light cleaning, deposits don’t have the chance to build up, thereby making cleaning easier and reducing the damage to the stainless steel layer.
Thorough rinsing of any cleaning product will ensure a long lasting finish. To avoid any drying streaks the surface can be wiped with disposable wipes or using a blown air drier.
Use the right Tools
As discussed mechanical abrasion can scratch the surface of your product which can cause corrosion. Use the proper tools to clean your products:
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Do Use |
Don't Use |
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Use the right Cleaning Products
As well as using the correct tools, using the correct cleaning chemicals is key.
Regular cleaning with warm soapy water will deal with most problems. For more stubborn stains look to use an alkaline, alkaline chlorinated or non-chlorinated cleaners.
If other cleaning products such as bleach, citrus-based cleaners or deliming agents must be used these should be diluted and the product surface rinsed thoroughly after cleaning.
Go with the grain
Like wood - Stainless steel has a visible surface grain. It is important to polish and clean in the same direction as the grain.
The direction of the grain may change with different parts of the product such as handles etc that are made from separate pieces of steel.
Cleaning with the grain is especially important if you’re using anything more abrasive than a cloth. If you can’t see the grain then it’s best to play it safe and stick with a soft cloth.
Even the finest cleaning powders can scratch a mill-rolled finish.
Treat your water
Depending on where you live you may have either hard or soft water. Hard water leaves deposits behind that will break down the protective surface of the stainless steel.
Where practical the best solution is to install a water filtration system to soften your water. Where this isn’t a viable option, it’s a good idea not to let water stand on your stainless steel surfaces for prolonged periods of time.
Cleaning problems and solutions
Problem |
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Suggest Method |
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Comments |
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Routine cleaning / light soiling |
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Soap, detergent or dilute (1%) ammonia solution in warm clean water. Apply with a clean sponge, soft cloth or soft-fibrebrush then rinse in clean water and dry To avoid water marks, use clean rinsing water. Drying marks may be avoided using an air blower or wiping with clean disposable wipes. |
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Satisfactory on most surfaces Avoid the use of oily rags or greasy cloths. |
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Fingerprints |
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Detergent and warm water, alternatively, hydrocarbon solvent |
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Proprietary spray-applied polishes available to clean and minimise remarking |
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Oil and grease marks |
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Hydrocarbon solvents (methylated spirit, isopropyl alcohol or acetone). Cleaning agents should be approved for use under the relevant national environmental regulations and, in addition, prepared and used in accordance with the manufacturers or suppliers' health & safety instructions. Solvents should not be used in enclosed areas. |
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Alkaline formulations are also available with surfactant additions. |
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Stubborn spots, stains and light discolouration. Water marking. Light rust staining |
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Mild, non-scratching creams and polishes. Apply with soft cloth or soft sponge and rinse off residues with clean water and dry. To avoid water marks, use clean rinsing water. Drying marks may be avoided using an air blower or wiping with clean disposable wipes. |
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Avoid cleaning pastes with abrasive additions. Suitable cream cleansers are available with soft calcium carbonate additions, or with the addition of citric acid. Do not use chloride solutions. |
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Localised rust stains caused by carbon steel contamination |
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Proprietary gels, or 10% phosphoric acid solution (followed by ammonia and water rinses), or oxalic acid solution (followed by water rinse). To avoid water marks, use clean rinsing water. Drying marks may be avoided using an air blower or wiping with clean disposable wipes. |
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Small areas may be treated with a rubbing block comprising fine abrasive in a hard rubber or plastic filler. Carbon steel wool should not be used, nor should pads that have previously been used on carbon steel. A test should be carried out to ensure that the original surface finish is not damaged. |
NB: Where possible, after cleaning, rinse thoroughly with water and wipe dry.