The reheating mistakes most home cooks make, according to a professional chef
From genuinely risky rice to eggs that can explode, not everything deserves a second round in the microwave.
We have all done it. A busy week, a fridge full of leftovers, and the optimism that last night’s dinner will taste just as good warmed up. Sometimes it does. Often it doesn’t. And occasionally, it really shouldn’t.
Reheating food is one of those habits most of us do on autopilot, but Mimi Morley, Senior Recipe Development Manager at recipe box provider HelloFresh, who has spent over a decade thinking professionally about how food behaves, says the mistakes people make are usually less about laziness and more about not understanding what heat actually does to certain ingredients.
“The honest answer is that most people reheat food the same way regardless of what it is,” she says. “Same appliance, same setting, same amount of time. But chicken, rice and vegetables all respond differently to heat. That’s where it tends to go wrong.”
Rice
Of all the foods on this list, rice is the one where the stakes are highest and the public awareness tends to be lowest. Uncooked rice can contain spores of Bacillus Cereus, a bacterium that survives the cooking process if left for too long, even if refrigerated.
Mimi is clear about where the real danger lies. “Everyone blames the microwave but the microwave is innocent here. The risk window for rice is actually those hours between cooking and refrigerating, not the reheating itself. People leave a pot of rice on the hob, forget about it, and then think blasting it the next day fixes everything, but it doesn’t.”
Her advice is to cool rice within an hour of cooking, refrigerate it promptly, treat it as a one-day leftover rather than something that can sit in the fridge indefinitely, and then as with anything reheat until piping hot (whether that’s in the microwave or stir frying).
Eggs
Scrambled, poached or fried, reheated eggs have a tendency to become something quite grim. The proteins in eggs are delicate structures that tighten quickly under heat, which is why they cook so fast in the first place. Apply heat a second time and those proteins contract further, producing the rubbery, faintly sulphurous result that has put many people off leftover eggs entirely.
“Hard boiled eggs are the one I always warn people about specifically,” Mimi says. “Reheating a whole boiled egg in a microwave is genuinely dangerous. The steam builds inside the yolk with nowhere to go, and they can explode, sometimes after you’ve already taken them out and cut into them.”
Her suggestion for leftover scrambled eggs is to repurpose rather than reheat, folding them into a wrap or stirring them through fried rice with fresh additions, rather than returning them to the microwave as they are.
Chicken
Reheated chicken divides people. Some swear by it, some find the texture changes too much to make it worthwhile. Chicken breast in particular becomes dry and slightly grainy when reheated with dry heat, as the proteins tighten and moisture escapes.
“The thing nobody tells you about leftover chicken is that the cut matters enormously,” Mimi says. “Thigh meat holds up to reheating better than breast because the higher fat content gives it somewhere to go. A splash of water when reheating can help a lot.”
She also raises the temperature issue plainly. Chicken must reach 75 degrees Celsius all the way through, not just on the surface, which makes the low setting on a microwave a genuinely bad idea.
Potatoes
Cooked potatoes left to cool at room temperature can develop bacterial growth in the right conditions, particularly baked potatoes that were wrapped tightly in foil, which can create an environment where certain bacteria thrive. The more immediate concern for most people, though, is what reheating does to the texture.
That said, cold potatoes stored safely in the fridge are a different matter entirely. “There’s actually something quite interesting about cold cooked potatoes that most people don’t know,” Mimi says. “When they cool down, they develop resistant starch, which behaves differently in the body and is genuinely beneficial for gut health. So eating leftover boiled potatoes cold in a salad is arguably better for you.”
Seafood
The smell alone is usually enough to deter people from reheating fish in any shared kitchen, but the quality argument holds up regardless of company. Fish proteins are particularly sensitive to heat, which is why fish cooks so quickly to begin with, and a second round of heat tends to push it past the point of pleasant eating. Shellfish carry a separate concern, as bacteria multiply quickly in cooked prawns or mussels that have not been refrigerated fast enough.
“The thing that gets overlooked with leftover fish is that cold is often the answer rather than no answer,” Mimi says. “Leftover salmon, leftover trout, leftover mackerel, all of these are genuinely good eaten at room temperature the next day with something acidic alongside them. People default to the microwave because that’s what they’re used to, but fish that has never been reheated is almost always better than fish that has. The acidity of a dressing or some pickled vegetables does more for day-old fish than any amount of gentle warming.”
