Why does my toaster burn one side of the bread?

Each toaster slot has heating elements on both sides, usually a wire on a mica board behind a mesh. They fail individually, and a toaster with one dead element browns one face and leaves the other pale — which people describe as burning one side, because the good side has to do all the work while the timer runs on.

Safety

Step by step

1. Do the glow test in a dim room.Run the toaster empty on a medium setting and look straight down into the slot. Both walls should glow orange evenly from top to bottom. Do not touch anything and do not put anything in the slot.
2. Read what the glow tells you.One wall dark: that element has failed and the toaster is at the end of its life. One wall glowing at the top only: a broken element wire. Both glowing evenly: it is not an element fault and the cause is elsewhere.
3. Check whether a single-slice or bagel setting is engaged.Many toasters have a bagel mode that deliberately heats only the inner element of each slot, and a single-slice mode that powers one slot only. Either produces exactly this complaint and both are easy to leave on by accident.
4. Look at the bread itself.An uneven slice, a slice cut thicker at one end, a slice much smaller than the slot, or bread straight from the freezer all brown unevenly. Try a fresh, evenly cut slice from a shop loaf as a control.
5. Check the slice is centred and held by the guides.Most toasters have sprung wire guides that hold the slice midway between the elements. If a guide is bent or a spring has gone, the bread rests against one side and scorches there while the other side barely browns.
6. Empty the crumb tray and clear the slots.A build-up of crumbs under one side reflects and holds heat unevenly, and it is a genuine fire risk in its own right. Unplug, slide out the tray, empty it, then turn the toaster upside down over a bin and shake gently.
7. Compare the two slots against each other.If one slot is fine and the other is not, that isolates it to the bad slot's element or guide. If both slots misbehave identically, look harder at the bread and the settings before condemning the appliance.
8. Retire it if an element has failed.Toaster elements are not a replaceable part on domestic machines: the casing is riveted or clipped in ways not designed for reassembly, and the elements are live components on mica boards. A toaster with a dead element is replaced.

Tips

• Cut your own bread more evenly, or buy a loaf sliced by machine, before blaming the toaster. Hand-cut wedges are the most common cause of one dark side.
• Toast from frozen on the defrost setting rather than a higher browning number. The higher number burns the surface before the middle thaws.
• Clean the crumb tray weekly. It is a fire risk and it is the maintenance item on a toaster that nobody does.
• Never fish toast out with a knife, even unplugged. Unplug, turn the toaster upside down, and shake it out.

Common mistakes

• Putting a knife or fork into the slots — The elements are live while the toaster runs and are exposed behind a thin mesh. It is the classic domestic electric shock and it is entirely avoidable.
• Turning the browning up to compensate for a dead element — It burns the working side further while the dead side stays raw, and it runs a failing appliance harder. The uneven result is a symptom, not a setting problem.

If it doesn't work