Most people evaluate a mug by looking at the front of it. The front is the part the maker spent the most effort on and the part that tells you the least. Everything worth knowing is on the base, the rim, the handle joint and the weight in your hand.
To judge a ceramic mug, run six checks in order. Turn it over and look at the foot ring, which should be unglazed on its contact surface, smooth to the touch, and often marked with concentric trimming rings if it was shaped on a wheel. Balance it by the handle to see whether the mass sits over your grip. Press the rim to your lower lip to feel burrs your eyes miss. Check the upper handle joint for a sharp step or a hairline crack. Flick the rim and listen for a clear ring rather than a dull thud. Look inside at the corner where wall meets base. If all six pass, the decoration on the front can be whatever you like.
Key takeaways
- The foot ring should be unglazed where it touches the shelf, because glaze melts to glass and would fuse the mug to the kiln shelf during firing.
- The colour of the exposed clay on the base identifies the body: white to grey-white suggests porcelain, buff or tan suggests stoneware, and orange to red-brown suggests earthenware, which is more porous and chips more easily.
- Concentric rings inside the foot ring mean the piece was trimmed on a wheel while leather-hard, which indicates a person shaped that foot rather than a mould.
- A clear sustained ring when you flick the rim indicates a dense, fully vitrified, intact body, while a dull thud indicates either a crack or an underfired body.
- Gold or platinum lustre decoration rules out microwave use entirely, regardless of what the rest of the body could tolerate.
1. Turn it over: what the foot ring tells you
- Is it unglazed? It should be, at least on the contact surface. A fully glazed base means the piece was fired on stilts, which leaves three small sharp points, or that it is low-fired earthenware.
- Is it smooth? Run a finger around it. A properly finished foot has been sanded or wiped after firing. A rough one scratches every surface you set it on, and roughness is the clearest sign of a rushed finish.
- What colour is the exposed clay? Bright white to grey-white suggests porcelain. Buff or light tan suggests stoneware. Orange to red-brown suggests earthenware or a red stoneware.
- Are there trimming marks? Concentric rings inside the foot ring mean the piece was trimmed on a wheel. A perfectly flat featureless base usually means slip casting or press moulding, which is not a fault, just a different process.
- Does it sit flat? Set it on a level surface and press one edge. Any rock means the foot was trimmed unevenly or the piece warped in firing.
2. Feel the weight, and where it sits
Weight in isolation means nothing. Balance does. Hold the mug empty by the handle with your arm relaxed. A well-proportioned mug feels like the mass is centred over your grip. If it tips forward, the walls are thick at the rim relative to the base, which usually means the maker did not thin the top of the form during throwing.
Then think about what it is for. A thin-walled porcelain cup loses heat quickly, which suits espresso and suits tea you want at a specific temperature. A thick stoneware or enamelled body holds heat and suits a long slow coffee. Neither is better. A vintage-style enamel porcelain mug sits at the heavier end and stays warm accordingly, which is the point of that form.
Which body suits which drink?
| Body | Heat retention | Typical rim | Suits |
|---|---|---|---|
| Porcelain | Low, cools quickly | Thin, rings high and long | Espresso, tea drunk at a set temperature |
| Stoneware | High | Medium, lower clean tone | Long slow coffee |
| Earthenware | Moderate, more porous body | Thicker, duller tone | Decorative and casual use |
| Enamel over porcelain | High | Rolled or thickened | Holding heat, sturdier everyday use |
3. Check the rim with your lip, not your eyes
The rim is where the mug touches your face, and it is where cheap production shows fastest. A good rim is slightly rounded and consistent in thickness the whole way round. Press it lightly against your lower lip and you will feel a burr or a flat spot immediately that you would never see. Look for glaze that stops cleanly rather than beading into a thickened lip, and check for a hairline of exposed clay, which will stain and roughen.
4. Look at the handle joint
The handle is the part most likely to fail. On a handmade mug the handle is usually pulled from a lump of clay and attached at two points while both parts are leather-hard, and each joint should show a small smooth transition rather than a sharp step. Sharp steps concentrate stress and are where cracks start.
- Can you get two fingers through the loop comfortably? One finger through a small loop transfers the whole weight to a single knuckle.
- Is there clearance between the loop and the wall so your fingers do not touch the hot body?
- Hold the mug by the handle and tilt as if drinking. Does the handle keep your wrist neutral, or do you have to rotate?
- Look for a crack at the upper joint specifically. That is where drying stress concentrates.
Sculpted and moulded handles follow different rules. On a piece like this Santa Claus ceramic Christmas mug, the handle is part of the figure rather than a pulled loop, so the thing to verify is that the moulded section is solid where it meets the wall and that the seam has been cleaned up rather than left as a ridge.
5. Test the ring
Hold the mug loosely by the handle, or balance it on your fingertips, and flick the rim with a fingernail. A clear sustained ring means a dense, well-fired, intact body. Porcelain rings highest and longest. Stoneware gives a lower but still clean tone. A dull thud means one of two things: a crack somewhere in the body, or an underfired porous body that never fully vitrified. Both are reasons to put it down. This test only works if the mug can vibrate freely, so on a table it will thud regardless.
6. Look inside
The interior gets ignored and it is the part in contact with what you drink. You want an even glaze with no crawling, no bare clay and minimal pinholing. Check the bottom inside corner where the wall meets the base, because glaze pools there and pooled glaze sometimes crazes or bubbles. A rough interior is harder to clean and holds coffee oils.
If the interior is a dark colour you cannot see through, that is a design choice with a practical cost: you will not notice staining or residue until it is significant.
What is it rated for?
Microwave and dishwasher suitability comes down to the body and any metallic decoration. Vitrified stoneware and porcelain generally handle both. Any gold or platinum lustre rules out the microwave completely. Crackle glazes and matte surfaces survive dishwashers but degrade faster than gloss, since detergent is alkaline and slowly etches the surface. Hand-painted overglaze decoration keeps its look far longer under hand washing.
Most of our ceramic mugs are photographed with the base and interior visible for exactly this reason, and the same checks apply to the cups and tasting ware in the tea and ceramic art collection, where thinner walls and finer rims make the rim and ring tests more informative rather than less.
Frequently asked questions
Why is the bottom of a mug unglazed?
Because glaze melts into glass during firing and would fuse the mug to the kiln shelf. The contact surface of the foot ring is left bare, or the glaze is removed with wax resist before firing.
How can you tell porcelain from stoneware?
Look at the exposed clay on the foot ring. Porcelain reads bright white to grey-white, stoneware reads buff to light tan. Porcelain also rings higher and longer when flicked, and is usually thinner at the rim.
What does it mean when a mug sounds dull?
Either the body contains a crack that is damping the vibration, or the piece was underfired and never fully vitrified, leaving it porous. Both shorten the life of the mug and neither improves with use.
Can hand-painted mugs go in the dishwasher?
Overglaze painting sits on top of the fired glaze and is the most vulnerable decoration to alkaline detergent, so hand washing preserves it much longer. Underglaze decoration, sealed beneath the glaze layer, is far more robust.
