Busting the myth about microwaving aluminium

Salted water boils faster, alcohol burns off when heated and refrigerated bread lasts longer. Cooking myths can often be convincing, but despite being engrained into our kitchen habits, not all of them are true. But what about the rule to never microwave aluminium?

At one time or another, we’ve all been warned not to use metal in a microwave. Without getting into the science of it, metals reflect microwave energy, causing the kind of snap, crackle and pop you probably didn’t expect from your breakfast. That said, there are ways to use aluminium safely in the microwave.

The United States Department of Agriculture (USDA) has a list of safe and unsafe containers for microwaving, as well as guidelines for cooking safely. It explains that some food packaged in foil containers can be safe to microwave. Acting in the same way as the metal walls inside the microwave, the sides of an aluminium tray shield the meal and protect it from overcooking — rather than reflecting dangerous radio waves.

Using aluminium trays in food packaging doesn’t necessarily mean the meal in question cannot be microwaved. However, it is essential to confirm this fact with your food packaging supplier before making any microwaveable claims to the customer.

As with all cooking myths, there will always be customers who fear the consequences of using an aluminium tray in the microwave, despite it being proven to be safe. However, providing these customers follow a few simple rules, there is no risk of opting for the microwave when cooking a ready meal in an appropriate aluminium tray. For food manufacturers, be sure to highlight these steps on your packaging.

To microwave an aluminium tray safely, the meal must not touch the walls of the microwave itself. Additionally, only one aluminium tray should be used in the microwave at one time and, as with most microwavable meals, aluminium or not, the lid must be removed from the tray before use.

Cooking myths do tend to have a little truth behind them. You should only microwave aluminium trays that are designed to do so. But in today’s convenience-heavy ready meal market, they all should be, right?

Image credit: ©iStockphoto.com/Joe Gough