A saucepan of boiling water is one way to cook sweetcorn, but for one or two cobs the microwave is often faster and creates less washing-up. The main challenge is that the cob can be very hot even when the surface looks dry. Steam trapped inside the husk or wrapping can burn your fingers if you tear it open carelessly.
Whether the corn is still in its husk changes the method. Husk-on cobs can steam inside their natural covering, while cleaned cobs need a suitable microwave-safe dish and moisture control. Follow the appliance's instructions and check that the kernels are properly heated.
Choose a fresh cob
Fresh sweetcorn should have plump kernels and no signs of mould or decay. If buying with husks, look for green leaves and a reasonably moist silk rather than badly dried brown outer layers.
The sweetest corn loses quality as it sits after harvest. Refrigerate according to the retailer's guidance if you aren't cooking immediately.
A cob with obvious rot isn't made suitable by microwaving.
Decide whether to leave the husk on
For husk-on corn, the covering helps trap moisture while the cob heats. Some recipes microwave the cob intact and remove the husk afterwards.
For pre-trimmed supermarket corn, the kernels may be exposed and need a covered microwave-safe container.
Do not assume plastic supermarket wrapping is microwave-safe. Remove packaging unless the label explicitly permits cooking in it.
Remove any obvious damage
Inspect the ends and trim away damaged stalk pieces as required. If using a husked cob, remove excessive dry dangling leaves that could touch interior surfaces.
Don't use metal ties or staples in the microwave.
If there are insects or soil around the husk, clean as appropriate before cooking. Wash hands and utensils after handling raw produce.
For a husk-on cob
Place the cob in the microwave as the recipe or appliance guidance recommends, ensuring it sits safely on the turntable.
Cook on an appropriate power setting. Because microwave ovens vary, begin with a cautious time suggested by a reliable recipe and add short intervals as needed.
Let the cob stand briefly after heating. The trapped steam helps finish cooking and must be released carefully.
Remove the hot husk safely
Use heat-resistant gloves or a clean kitchen towel to handle the cob. Pull back the husk away from your face to avoid a sudden burst of steam.
The silk may come away more easily after cooking. If needed, remove remaining strands with suitable utensils.
Don't grip the steaming cob with bare hands just because the outer leaves appear cool.
For an already shucked cob
Put the cleaned corn in a microwave-safe dish with a small amount of water if required. Cover with a microwave-safe vented lid or appropriate cover.
The aim is to trap enough steam to cook without letting the dish dry out.
Do not seal a container completely airtight. Steam pressure needs a safe release path.
Calculate timing sensibly
A medium fresh cob may cook in a few minutes in a typical microwave, but the right time depends on wattage, quantity and initial temperature.
For two cobs, arrange them so heating is as even as possible. Adding more cobs doesn't necessarily mean simply multiplying a one-cob time.
Follow the appliance or suitable recipe's guidance, then check the result and add short intervals if required.
Rotate and stand
If your microwave has no turntable, reposition the dish when its instructions recommend doing so.
Allow standing time after heating, because temperature may continue equalising inside the cob.
A thick cob can have hot outer kernels and less hot parts near the centre. Careful standing and checking help.
Check the kernels
Cooked sweetcorn should be hot, tender and pleasantly juicy. Test a few kernels after allowing enough cooling to avoid burning your mouth.
Overcooking can make the kernels dry or chewy. If they feel tough because the corn is old, more microwave time may not restore sweetness.
Don't keep running long heating cycles just to chase a particular number on the clock.
Add butter after cooking
A little butter, pepper and salt are classic. Spread the butter while the cob is hot enough to melt it.
You could also use lemon, lime, smoked paprika or finely chopped herbs.
Avoid putting a thick metallic butter wrapper into the microwave. Remove all packaging first.
Corn with chilli and lime
Mix lime juice, a little suitable oil or butter and a pinch of chilli flakes for a simple dressing.
Brush it onto the cooked kernels rather than adding large quantities of acidic liquid before cooking.
A little grated cheese can be pleasant, but keep toppings proportionate to the cob.
Serving children safely
A whole corn cob is awkward for some young children to bite and handle. Remove kernels or prepare as appropriate for the child's age and abilities.
Be alert to choking hazards and hot kernels. Allow adequate cooling before serving.
Follow NHS guidance for safe preparation of food for babies and young children rather than assuming every vegetable is harmless in any shape.
Can frozen corn cobs be microwaved?
Many frozen packs include microwave instructions. Follow those instead of using a method designed for fresh husked corn.
Frozen cobs start much colder and often need different covering, timing and standing.
Don't microwave an unsuitable plastic bag just because it contains frozen vegetables.
What about pre-cooked corn?
Vacuum-packed ready-cooked corn may simply need reheating. Check the package for whether it's cooked and how it should be heated.
Avoid treating a ready-to-eat product as though it's completely raw and cooking it until the kernels shrink.
If the packaging is damaged or expired beyond safe use, don't use heat as a rescue method.
Clean up condensation
After removing the dish, carefully pour away any water using oven gloves. Steam and hot droplets can cause burns.
Wipe up spills once the microwave interior is safe to touch. Dried sugar from corn can become sticky.
Use a clean serving plate rather than placing cooked food back into an unwashed preparation tray.
Microwaving several cobs for a family
For a large batch, steaming or boiling in a saucepan may be simpler and more even than trying to balance many cobs in a microwave.
If you do use the microwave, cook manageable portions and keep completed cobs covered briefly until serving.
Don't pile hot cobs into a tightly sealed container where people may be surprised by trapped steam.
The everyday method
Use the correct method for husked or shucked corn, keep the dish microwave-safe, heat in sensible intervals and let steam escape carefully.
The microwave works particularly well for a couple of fresh cobs. You'll spend more time choosing a topping than you will washing a saucepan.