Microwaves: How we test
Our microwave testing mimics the tasks you'll perform in your own kitchen but with the help of some quite unusual testing equipment.
Temperature and evenness
The "hedgehog" test the temperature
The main tests involve heating a special food substitute to see how evenly it cooks, and whether all parts reach a safe temperature. We also check if the food shrivels or dries out.
To do this, we use a substance called TX151 which is bright blue and has a similar consistency to a lasagna when it's cooked in a microwave.
Unlike lasagna, though, it's easy to produce a number of identical trays of TX151, so every microwave is given exactly the same thing to heat.
TX151 food substitute
We also cook jacket potatoes, assessing their appearance and the quality of the cooked potato.
Defrosting
To test how evenly a microwave oven will defrost meat, we use lean minced beef, shaped to specific dimensions and frozen for at least 12 hours.
We defrost the meat and leave it to stand for five minutes before testing the temperature. We work out the maximum and minimum temperatures of the meat and check if there are any hot or cold spots in the defrosting.
A bad defroster will start to cook parts of the mince while other parts are still frozen.
Temperature checking defrosted mince
Under the grill
Our grill test involves state-of-the-art technology. As with conventional grills in a traditional oven, we’re mainly looking for even browning.
Poorer models tend to over-brown the food, usually in the centre, while leaving the outer edges pale. They need to get the timing right too as, if it takes too long, food can dry out during the process.
To measure this, we load the microwaves’ grill trays with crustless white bread, cut to fit the grill shape, and grill on the maximum grill setting recommended. We then toast until as much toast as possible meets our desired shade without any burnt parts.
Our computer analyses how evenly toast browns
Our equipment then photographs the toasted bread, converts the colouration into a chart representing temperature and analyses objectively how much of the toast meets the desired colouration and, crucially how much difference there is between the most and least coloured parts.
Chicken test
For combi models, we roast a whole chicken. We score each model on speed of cooking, and downgrade any that under- or over-cook, using probes to check the temperature and the evenness of cooking. Our testers also assess skin crispiness and the colour and texture of the meat.
Safety first
We test microwaves for radiation leaks and electrical safety. We also check if they can be damaged if you accidentally run programs without food inside them and whether they can safely contain flames caused from sparking if metal items are put in by mistake.
Ease of use
We assess how easy it is to program microwaves, understand their controls, and do simple tasks such as opening and cleaning them. These tests include a special assessment from the perspective of people with poor vision or dexterity.