Tea leaves a ring. First it's faint, then it's a brown band that sits right at the fill line no matter how many times you rinse the mug. It's tannin, the same compound that gives tea its color, and once it bonds to the surface a splash of water won't touch it.
The short answer. Baking soda paste lifts a light stain in under two minutes. For a ring set in for weeks, soak overnight in equal parts vinegar and warm water, then follow with a baking soda scrub. Both work on stainless steel and ceramic. Skip the steel wool — it scratches the powder coat and can weaken the vacuum seal.
By Chen Deng, founder — LAMOSE, Calgary, Alberta
Light stains: baking soda, two minutes
Rinse the mug with hot water first, to clear loose tea leaves. Mix two tablespoons of baking soda with one tablespoon of warm water into a paste, spread it over the stain, and scrub gently in circles with a soft sponge for a minute or two. Let it sit five to ten minutes on anything stubborn, then rinse and dry. Baking soda is mildly alkaline, which is exactly what neutralizes the acid in tannin stains without scratching the steel.
Set-in stains: vinegar soak, then baking soda
Fill the mug with equal parts white vinegar and warm water and let it sit at least four hours, ideally overnight, lid off. Dump the vinegar, sprinkle in two to three tablespoons of baking soda with a little water to make a paste at the bottom, and scrub the corners and base where stains hide. Rinse three times to clear any vinegar smell, then air-dry upside down.
A denture-cleaning tablet does the same job with less scrubbing: drop one in, fill with warm water, and let it fizz for 15–30 minutes before rinsing.
What actually damages your mug
| Do | Don't |
|---|---|
| Rinse right after you finish drinking | Let tea sit in the mug overnight |
| Use a soft sponge or bottle brush | Scrub with steel wool or an abrasive pad |
| Hand wash insulated tumblers | Run an insulated tumbler through the dishwasher |
| Clean the lid and threading weekly | Store the lid on tight while the inside is still damp |
Best for daily tea
LAMOSE Peyto 12 oz / 16 oz Tumbler
18/8 stainless steel, double-wall vacuum insulated, splash-proof lid. The same wide opening that makes tea easy to brew in also makes it easy to reach every corner with a sponge. Free permanent engraving, made to order in Calgary.
Frequently asked questions
Why do tea stains form in the first place?
Tea contains tannins, the compounds that give it color and a slightly dry taste. Left sitting in a mug, tannins oxidize and bond to the surface, and hard water minerals make the bond stronger. Rinsing right away is what keeps them from setting.
Can I use denture tablets to clean my mug?
Yes. Drop one or two into the mug, fill with warm water, and let the fizzing action work for 15 to 30 minutes before rinsing. It works on both ceramic and stainless steel.
Is baking soda safe on stainless steel?
Yes. It's mildly abrasive and mildly alkaline, enough to lift a tannin stain without scratching the interior or the powder-coated exterior. Skip anything more abrasive than a soft sponge.
Can I put my insulated tumbler in the dishwasher?
No. Dishwasher heat and detergent can damage the powder coat and, over time, weaken the vacuum seal. Hand wash with warm water and a soft sponge instead.
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