Are Mugs Microwave and Dishwasher Safe?
Most mugs are safe in both the microwave and the dishwasher. The exceptions are consistent and easy to identify once you know what to look for, and the difference between a mug that lasts a decade and one that looks tired within a year is almost entirely about how it is washed.
Microwave: what is safe and what is not
Safe
- Glazed ceramic, stoneware and porcelain without metallic decoration
- Plain glass and borosilicate glass
- Most printed and sublimated designs
Not safe
- Anything with gold, silver or metallic trim. Metal reflects microwaves, sparks and can damage the oven.
- Stainless steel and insulated mugs. Never, under any circumstances.
- Mugs with an unglazed base. Unglazed clay absorbs water, which then heats unevenly and can crack the mug.
- Decorative lids — many have metallic or hand-applied elements. Remove them.
How to tell if a mug is microwave safe
Check the base for a symbol or wording first. If there is nothing, look for metallic decoration and feel the foot ring — rough and porous means unglazed. As a last resort: put the empty mug in the microwave alongside a cup of water and heat for thirty seconds. If the mug is hot and the water is not, it is absorbing energy and should not be used.
Dishwasher: what is safe and what is not
Safe
- Glazed ceramic and stoneware
- Most single-wall glass
- Printed and sublimated designs, which are heat-cured
- Most enamel and single-wall stainless steel
Hand wash instead
- Gold and metallic rims. Repeated hot cycles dull and eventually strip them.
- Hand-painted designs. Detergent fades hand-applied color.
- Double-walled glass. Water can get trapped between the layers.
- Travel mug lids. Take them apart and wash the gasket by hand.
- Studio pottery with an unglazed foot. It absorbs water and takes a long time to dry.
Loading mugs properly
The most common cause of chipped rims is not the detergent, it is mugs knocking against each other during the cycle. Space them so they do not touch, place them upside down on the top rack, and make sure tall mugs are not tipping into the spray arm's path. Mugs that fill with water during the cycle are sitting at the wrong angle.
Removing coffee and tea stains
Make a paste of baking soda and a few drops of water, rub it around the interior with a cloth or your fingers, leave it a minute, then rinse. This lifts set-in tannin stains without scratching. Never use an abrasive scourer — the fine scratches it leaves are exactly where future stains take hold, so it makes the problem permanently worse.
For a stubborn stain, fill the mug with hot water, add a tablespoon of baking soda and leave it overnight. Matte and speckled glazes stain more readily because of their surface texture, so rinse those soon after use rather than leaving drinks to sit.
Thermal shock: the thing that actually breaks mugs
Ceramic and glass crack when different parts change temperature at different rates. In practice: do not pour boiling water into a mug that has come out of a cold cupboard in winter, do not put a hot mug straight into cold water, and do not pour a hot drink into a mug taken from the freezer. Warming a thin mug with hot tap water first takes five seconds and prevents nearly all of it. Borosilicate glass and high-fired stoneware tolerate this far better than earthenware or ordinary glass.
When to retire a mug
Crazing — the fine web of cracks in an old glaze — is normal, but once stains sit visibly in those cracks the surface is no longer sealed and the mug is past its best. A chip on the rim where your lip goes is a reason to stop using it. A chip elsewhere is cosmetic.
Frequently asked questions
How can I tell if a mug is microwave safe?
Check the base for a symbol, look for metallic decoration, and feel whether the foot ring is glazed. If in doubt, microwave the empty mug next to a cup of water for thirty seconds — if the mug heats and the water does not, do not use it.
Are ceramic mugs dishwasher safe?
Glazed ceramic and stoneware are. Hand-painted designs, metallic rims and unglazed bases should be hand washed.
Can insulated mugs go in the microwave?
No. The stainless steel body reflects microwaves and can damage the oven.
Why did my mug crack when I poured boiling water in?
Thermal shock. The mug was too cold, so the inside expanded faster than the outside. Warm thin mugs with hot tap water first.
How do I get coffee stains out of a mug?
A baking soda paste rubbed around the interior. Avoid abrasive scourers, which scratch the glaze and make future staining worse.
Does the dishwasher fade printed mug designs?
Properly heat-cured prints hold up for years. Use a normal rather than intensive cycle to keep colors brightest, and hand wash anything hand-painted or metallic.
Care by material
See ceramic mugs, stoneware mugs, glass mugs and insulated mugs — each product page states its microwave and dishwasher status.