≡ Menu

Most people know two things that you should never do to a microwave oven. The first is to run it with something metal inside, and the second is to run one when it’s empty. It’s the second one of those that I’m concerned with right now.

If you do run your microwave with nothing inside, the magnetron (which is the component that produces the microwaves) will overheat, often causing irreparable damage.

There are, believe it or not, some “entry level” microwave ovens that don’t have a start button. The ones that have a keypad are OK. They all have a “start” pad. It’s just the manual ones, with one dial to set the time and another dial for the power level, that are the problem.

Now, you may be wondering how you start a microwave oven with no start button! Well… As you set the cooking time, you simply twist the timer knob and it starts to microwave as you start to twist… So far, so good.

The problem starts when your coffee begins boiling away inside your microwave, before the timer has run down to zero. So you open the door, take out your coffee, shut the door… and what do you suppose happens? You’re right smartypants! The microwave starts cooking again with nothing inside the cavity! Now you may remember to turn the timer dial back to zero, but if you’re busy, you may not… in which case the magnetron will get hotter and hotter until it self destructs!

A better designed machine would have a mechanism that resets when you open the door, preventing the microwave from heating again when the door is closed, until you press the start button.

Daewoo KOM9M11S

If you’re wondering where you can find a microwave like that, look no further than the Daewoo KOM9M11S which is only £249 + VAT

I will sell you one without a start button, if that’s what you really want, but you’re here because you want the best advice… right?

Fire chiefs are urging residents to take care when using wheat bag “hot water bottles” after being called to an increasing number of incidents over recent years.

The warning comes following an incident that occurred in Brough late March, which extensively damaged a kitchen.

A Humberside Fire and Rescue spokesman, Pete Baron, said “most wheat bag fires start in the microwave due to the bag being heated for too long, often devastating the kitchen and sometimes affecting the whole house”.

Wheat bag “hot water bottles” are cushions and soft toys that are filled with wheat. They are designed for comfort and therapy by heating up the wheat in the microwave.

It may be difficult for people to believe that a product designed to offer comfort and therapy could pose a danger. However, the importance of following the manufacturer’s instructions cannot be stressed enough. If wheat bags are not used properly it can have devastating effects.

Ensuring that your product conforms to British Standards is essential. It is equally important not to allow anyone who is not aware, or is unable to understand the instructions, to heat them up.

The instructions should be on the bag itself and any outer covering that it may have. If you are not able to follow the instructions, it must not be used.

Fire and Rescue Services are urging residents to take care when using wheat bags, follow the manufacturer’s instructions and never overheat them.

It is also very important to know that your microwave turntable is working correctly and that oddly shaped items, such as teddy bears, are able to rotate fully in the microwave.

If the wheat bag is not turning properly it can create hot spots caused by uneven heating of the bag.

If the wheat bag is then insulated, for example if it is put under bedding, spontaneous heating can continue, leading to the wheat bag catching fire, which is vividly illustrated in this video.

Homemade wheat bags pose a different type of danger as the exact weight is not known so it is difficult to know how long to heat the product for.

Adding scented oils to wheat bags means that over time the cloth and the grains become saturated, which can lead to overheating of the wheat while the oil provides additional fuel, presenting even more of a risk.

Since 2002 the numbers of incidents involving wheat bags has remained fairly constant but in 2010 the numbers of incidents increased by 500 per cent compared to 2009.

In the UK, fires starting from wheat bags are known to have caused three deaths and injury to an elderly couple.

You have been warned!

A lot of people worry about the safety of microwave ovens and I often receive messages on that subject, so I thought I’d publish this article, in the hope that it’ll put everyone’s mind at rest!

We’re all aware of the light beaming down at us every day from the Sun, and most of us know that white light is made up from different colours, which we can sometimes see in the spectrum of a rainbow.

What fewer people are aware of is that the visible spectrum is just a tiny part of the much bigger electromagnetic spectrum.

Even though we can’t see them because of the limitations of our eyes, a lot of the other frequencies are harmlessly beaming around us all day long, totally invisible.

Now, not all these different frequencies that come from the Sun can get through the Earth’s atmosphere and fortunately most of the harmful ones are stopped before they get here.

I mentioned “harmful ones” and there are some (NO! Not microwaves!) which some of you will already be aware of.

If you look at the illustration below you’ll see the visible spectrum in the middle with red at one end, followed by orange, yellow, green, blue, indigo and violet at the other end.

Electromagnetic Spectrum

As the wavelength gets shorter beyond violet, we get to ultraviolet which is the first of what’s called ionizing radiation. It does have a cumulative effect on the body as you’ll know if you like to lay in the sunshine, as it turns the skin brown. Too much ultraviolet and skin cancer can be the result.

Even shorter wavelengths beyond ultraviolet are X-rays and gamma-rays. X-rays have their uses as we know, but we can only have a limited exposure to them as the cumulative effect on the body is harmful.

So… what you need to remember is, that the electromagnetic spectrum is divided into ionizing and non-ionizing radiation. The dividing line is between violet and ultraviolet. Ultraviolet and shorter wavelengths. (Nasty!) Violet and longer wavelengths. (Nice!)

As the wavelength increases beyond red, we get infrared, microwaves and radio waves which are all harmless to us. At high power levels these do have a heating effect, but NOT a cumulative effect.

So if you could heat up your hand inside your microwave oven, you could damage it in the same way as if you plunged it into boiling fat! However if you just warmed your hand a little and then turned the microwave oven off it would soon cool down again, with NO lasting effect, in the same way as if you took your hand out of warm water.

As a side note, I should say that one of the reasons people worry is the use of the word “radiation” but it’s only used to describe the way the energy travels, in the same way that light radiates from a light bulb and heat radiates from a fire. Remember, there’s good (non-ionizing), as well as bad (ionizing) radiation!

A second side note now, as some people worry that even after you turn off your microwave oven, that somehow microwaves stay inside the food for a while. STOP IT! That’s just silly! That would be like your bedroom taking a few minutes to get dark after you turned off your bedside light.

The bottom line is this … If you’re standing in your kitchen, next to your microwave oven while it’s cooking, you’re in less danger from the microwaves than from the sunlight coming through the window!

Hi! My name’s John and my involvement with commercial catering equipment started in 1993 with the repairing and supplying of commercial microwave ovens. For over sixteen years now, we’ve been supplying equipment on line.

If you’re a professional caterer you’ll find great deals on all makes of commercial microwave ovens!

Check back soon.