It is a common occurrence for mugs used everyday to become badly stained by tea or coffee. The brown stains are unsightly and difficult to remove. Sometimes they become so bad that scrubbing in soapy water does not remove them. Clearly coffee and tea are strong staining agents!
“But what causes the staining?”
It is a combination of hard water, chemicals called tannins, and microscopically rough glaze surfaces. These conditions allow the stains to strongly adhere to the glaze surface. The staining is usually worse in the base of the mug or where there is a sharp corner to hold on to the stain.
“So how do I clean stained mugs?”
Various cleaning methods have been tried and tested including vinegar, bleach, baking soda and washing soda. All have been proven to be successful and are widely used. However Bar Keepers Friend and tooth cleaning powders are less likely to give long lasting damage to the glaze surface. Cleaning with other chemical compounds and scourers whilst successful can create damage to the glaze surface which will make them more susceptible to future staining. So please take special care with your best china or dinnerware and treat them gently for their long term protection.
“So how do I stop staining?”
Manufacturers of the top brands of dinnerware and mugs design their products to resist staining and damage in use. In essence this is done by ensuring the glaze is chemically and physically durable. However,with the widespread manufacture of mugs in many parts of the globe including Asia, it is not easy to know the source and quality of the ceramic mugs we buy.
It is almost impossible to assess how resistant mugs will be to staining by visual inspection. Smooth glaze surfaces with few corners will reduce the potential for the stain to adhere strongly to the surface. However, over time the glaze surface may be attacked by dish-washing agents. leading to the dreaded staining.
Cleaning the pottery soon after use with warm soapy water will certainly reduce the possibility of staining.
To reduce tea and coffee staining of your mugs, clean them as soon as possible after use in warm soapy water. Use quality mugs from top brands as they will have designed the mugs to be chemically and physically durable. Avoid harsh detergents for cleaning as this can damage the glaze surface and lead to greater staining. Bar Keepers Friend and tooth cleaning powders are preferred cleaners and less likely to create long term damage. If all else fails buy new quality mugs but recycle the old ones. Pottery is a truly 100% recyclable product!