Understanding Stainless Steel Tea Staining

Tea staining is a form of discoloration and corrosion that can occur on stainless steel surfaces, particularly in outdoor or high humidity environments. It is more common in coastal or industrial areas, where the air contains higher levels of salt and other corrosive particles.

While it is possible to prevent tea staining through proper cleaning and maintenance, it is still a relatively common issue that is encountered in many industrial and commercial settings. Tea staining on stainless steel is caused by environmental factors such as exposure to high humidity, high temperatures, water containing salts and minerals and accumulation of chloride and other minerals on the surface of the stainless steel. Other factors include poor air circulation, high air pollution, and exposure to chemicals and acids.

The combination of these factors can lead to a discoloured or stained surface of the stainless steel and is an indicator of corrosive environmental factors being present. Further indication of corrosive environmental factors in this application may be the predominant existence of tea staining on external surfaces where water is not continually washing contaminants away from the stainless steel.

While tea staining can impact the appearance and aesthetics of the stainless steel, it is not considered materially degrading or corrosive, but it can be a useful indicator of the presence of conditions that can lead to forms of corrosion such as pitting or crevice corrosion.
From a more practical perspective, tea staining on 304 stainless steel demonstrates the importance of regular maintenance and cleaning of stainless-steel surfaces to maintain their appearance and prevent corrosion.

Our best advice recommends that removal of tea staining be completed by cleaning the surface with a mild detergent and water followed by rinsing the surface with clean water and dry it thoroughly.

If the staining persists, use a solution of equal parts white vinegar and water to remove the stain. Apply the solution to the stained area and let it sit for 10-15 minutes before rinsing with water. For yet tougher stains, commercial stainless-steel cleaners and polish are available.
To maintain the stainless steel and prevent tea staining in the future: Regularly clean the surface with a mild detergent and water. Keep the surface dry and avoid prolonged exposure to moisture and high humidity. Avoid exposing the stainless steel to chemicals and acids that can cause corrosion. Regularly inspect the surface for signs of corrosion and address any issues promptly.

Additionally, using a higher grade of stainless steel, such as 316, may be more resistant and therefore offer greater resistance to tea staining.
If you have any questions regarding tea staining, contact your local BAC Representative.

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