How to Remove Tea and coffee stains from your Ceramic Mugs

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.

"Summary"

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!

More information and other technical articles on pottery and ceramics can be found at my website The Potters Friend. Go now to sign up for my free newsletter.

Is Your Pottery Microwave Safe?

Microwave ovens are now a common feature in most kitchens. Their use both to heat and cook food means a wide range of ceramics is being used in microwave ovens. However the question remains….Is all pottery microwave safe?

Technically this question is a little more complex than it appears. There are general rules such as:-
“do not use ceramics decorated with gold, silver or precious metal in microwave ovens”

 Indeed ceramic with any metal should not be used in a microwave oven. However additional rules depend on recognising which type of ceramic is being used. For the consumer this is not an easy task.

All ceramics are not the same!

Ceramics are now made all over the world and it is not always easy to establish their source or quality or type. However ceramics that have been fired to a high temperature and are non porous are generally considered to be acceptable for use in microwave ovens. These ceramics include stoneware, porcelain, bone china, and vitreous cookware. Other ceramics which have not been fired to a high temperature have to be used with caution. For these type of product to be used safely there is a need to ensure that they are both dry and have not absorbed water. This can happen in many circumstances particularly during washing or in storage in the fridge. These products need extensive safety instructions to be used safely.

Top brands help the consumer by labelling their products as ‘microwave safe’. Less well known products cannot give this assurance and often do not label at all. So buyer beware and if in doubt do not use in a microwave. Look out for BS or CE standards as a sign of meeting a quality standard.

In summary, most high fired ceramics are suitable for microwave oven use. Lookout for the labelling used by branded products to give reassurance on acceptability for microwave oven use. If in doubt “keep out” is a good motto to remember!

Why not test your pottery knowledge with my quick pottery quiz

More information and other technical articles on pottery and ceramics can be found at my website The Potters Friend

Go now to sign up for my free newsletter.

Pottery Clinic

Glaze blister at high magnification

Post your questions about any pottery or ceramic matter.

All questions are welcome regardless of how simplistic they may appear !

My commitment is to respond in a timely fashion and to provide the best advice that I am able to based on my own perspective and the information provided.

I look forward to answering your questions