Everyone has their own favourite coffee mug, one that feels right in the hand and seems to round out a perfect morning experience. Eventually, even the prettiest mugs start to tell a story, each ring representing the cup of Earl Grey tea or espresso served up in it. The rings are stubborn little guys who won’t come off in the dishwasher but manage to create an ever-so-slightly dingy appearance for the cupboards that house them. It’s commonly believed that there is no way to remove such marks once they’re made.If you want that spotless look of your interior back, you already know where to start looking beside your boxes of flour and sugar – baking soda is more than a rising agent for cakes. It’s an efficient and scientifically proven tool in the battle against stains and odours. We often use it like it’s a magic trick, but sodium bicarbonate combines with the pesky stains and does its magic without the need to scrub vigorously and inhale fumes.The science of why coffee and tea leave stains on your cupCoffee and tea are abundant in tannins and chromogens – compounds that are natural colouring agents. They adore even the slightest imperfections in the surface of your cups and stick around there. The problem is that their bond with the ceramic or porcelain surface cannot be easily broken with regular water washing.
Baking soda’s alkaline properties also help to separate acidic stains from the cup’s surface, restoring a spotless appearance. Image Credits: Google Gemini
A Journal of Dentistry research paper will give an idea of what pigmented materials can do. Even if it concerns only enamel and beverages, it should be noted that the same principle works for your crockery. The constant contact between food and drink that contains tannins leads to a layer of stains building up; therefore, even thin discolouration may harden into dark crusts.Why baking soda works best at polishing your cupThere is one particular characteristic that makes baking soda special. As a matter of fact, chemists call it a mild abrasive. When you mix a small amount with water to get a paste, you get a mini polish kit. Unlike metal brushes or sponges that will scratch your ceramic, baking soda particles are soft enough to remove discolouration.A comprehensive review published in The Journal of the American Dental Association, titled Stain removal and whitening by baking soda dentifrice, explores this exact mechanism. The review explains that baking soda has a very low abrasivity rating. Its crystal structure is designed to crumble under pressure, which means it provides enough friction to dislodge stain particles, but not enough to “sand down” the surface it is cleaning. This makes it the safest choice for everything from your daily office mug to your grandmother’s fine china.However, the use of baking soda does not end here because it is not only about scrubbing but also includes some chemistry. First, baking soda is a buffer solution, and what it means is that it pushes the surrounding solution closer to the alkaline side. Usually, stains formed due to tea or coffee are acidic in nature. This way, with the help of a buffering action, baking soda separates the stain from the cup.For optimal results, add one tablespoon of baking soda into a wet mug and make a paste by mixing it. Gently scrub the inside of the mug for a minute using circular motions, and the brown stain will start to disappear. Rinsing with hot water will not only give you a disinfected mug due to the antibacterial properties mentioned by the above-mentioned study, but it will also remove any bad smell.