Microwaves

A microwave on this list is a countertop box. The number that matters on the door is the wattage.

A 700 watt oven needs longer than a 900 watt oven for the same bowl of soup. Pack instructions that say "800 watts" are not a suggestion you can ignore if yours is weaker. Add time, and stir. The centre of a bowl stays cold while the rim boils, because the waves heat the outside first.

A turntable has a ring under the glass plate. If the ring is out of its track, the plate sits still and one side of the food overheats. A flatbed microwave has no ring. Do not put a metal turntable ring into a machine that did not come with one.

Foil, including the rim of some takeaway lids, sparks. A spoon left in a mug can do the same. Eggs in the shell burst. So do whole peppers with no slit. Covers should vent. A sealed plastic lid bows up and then dumps hot liquid when you lift it.

The cavity is small on compact models. A dinner plate that fits may still touch the walls, and food at the edge heats harder. Use a smaller plate rather than bending the tray.

Browning and crisping happen in the countertop oven, not here.