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Microwave vs Thermal Cooking

Over 99% of the energy on Earth comes from the sun through light waves. Energy (E) = Planck's constant multiplied by the frequency of the light. Thus, visible light is of higher energy compared to infrared.

Also, microwave energy is lower compared to infrared energy.

Some articles indicate that a thermal oven heats by conduction. This implies that neighboring molecules share energy and heat food from the outside. However, thermal energy is infrared energy. Stand at a distance from a campfire. You feel great warmth. However, the air between yourself and the fire is not that hot. You are being heated by the interaction of the emitted infrared light with your skin. Infrared light can penetrate up to an inch, heating you by absorption (interaction), not just conduction.

Air is not very dense, so it has a low heat capacity and cannot heat your skin very quickly. Try this experiment. Put your stove burner (metal element type) on high until it becomes red hot. Then, pass your hand over the element. You will feel great warmth. But as soon as you pass by the element - even at the very edge - you do not feel the same intense warmth. The air does not carry much heat. It is the invisible infrared light that is doing most of the heating.

Why does your burner turn red - that is, give off visible light? The red color of stove burners results from incandescence, where the heating element emits visible light due to its high temperature. The high temperature promotes electrons to a higher "excited state." The gap between the ground state and this higher excited state is in the visible region.

This shows that, even when you cannot see the infrared light from the heating element, it IS THERE!


Again, microwave energy is lower compared to infrared light. So why might the microwave oven be problematic wrt cooking?

The problem is not the type of light; instead, it is the intensity!

We know not to "char" our food by placing it too close to a hot heating element. When we do, the intensity is increased, and the food becomes sufficiently hot to "burn" it, producing potentially harmful byproducts. The same is true with microwave cooking.

How can a microwave oven with a lower energy source than a thermal (infrared) oven cook more quickly? It uses much higher intensity.

Food and water absorb the infrared light when cooking in a thermal (infrared) oven. In microwave cooking, a claim is made that the microwave energy is tuned to water alone. I doubt this is the case. Like with infrared light, almost all molecules (substances) absorb this form of light.


Here is an article that compares these two types of cooking appliances.

Here are key points from the article.

Conventional and microwave heating were compared, especially the way they affect the acrylamide (toxic substance) formation in food. Available studies demonstrate differences in the mechanisms of microwave and conventional heating.

The mechanistic difference is just the way substances interact with infrared vs microwave energy (light). Infrared light causes molecular vibration, while microwave light causes molecular rotation. Both generate heat.

The published studies showed that microwave heating at a high power level can cause greater AA formation in products than conventional food heat treatment.

How can a lower-energy form of light heat food faster? There is only one answer: the microwave oven uses a higher intensity of a lower-power light. It does this because Americans want their hotdog cooked in 30 seconds, not 5 minutes!

The best way to cook meat in a thermal (infrared) oven is slowly, at low temperatures. Microwave ovens do not (seldom) provide a "temperature" (energy) dial. Instead, the power setting pulses the energy but does not lower or raise it as in a thermal (infrared) oven. You cannot set a microwave oven to 350 F, for example.

"Microwave ovens are also widely used in everyday life for rapid food heating, particularly for so-called “convenient food” [15,20,35,60]."

"Microwave heating is caused by the ability of the products to absorb microwave energy and convert it into heat. Microwave heating of foods mainly occurs due to dipolar and ionic mechanisms. When food is placed in a microwave oven, various food ingredients behave differently. The main ingredient that enables foods to be heated by microwaves is water. The higher the water content of food, the faster the heating rate is [62]."

"Except for water molecules, the polar particles of food ingredients are also subjected to intense microwave field action, resulting in the rotation of the polar molecules. This extremely high rotation rate causes water molecules and the polar particles of food ingredients to collide with each other at a very fast rate. This creates friction between molecules, and it generates heat. The heat flows through the food by conduction, convection, or radiation, and food warms up [63]."

If you read the paper, the next paragraph after the one quoted above states that thermal oven energy is transferred by conduction. This is NOT true. There is conduction between heated molecules in both thermal (infrared) and microwave ovens. However, both heat by interaction with food molecules. In a thermal (infrared) oven, the air is also heated by interaction with the infrared waves. This happens to a lesser extent in microwaves. However, the microwaves heat any moisture in the air, and then that energy is transferred to the food by conduction as well.

"5. Conclusions

On the basis of the available data, it should be concluded that the formation of acrylamide in microwave-heated food, as in the case of conventional heating, depends on the process parameters and the properties of the processed products. The main advantage of microwave heating is the short duration of this process, but due to the possibility of uncontrolled and uneven temperature increase in individual layers of the product, which favors a greater amount of acrylamide forming, further research in this area should be carried out. (typical BS final statement by researchers that get their funding by never solving anything!!!)



  1. Microwave heating is most likely very safe with high-water-content foods and drinks because water's high heat capacity will disperse the heat. For example, heating soups and drinks like coffee will most likely not cause "super heating," which is the problem in solid foods.

  2. High-water-content foods, particularly beverages, are less likely to contain substances that can be converted to toxic byproducts.

  3. Buy and use a cheap, low-power microwave.

  4. Always use the power setting to pulse the microwave energy to reduce the possibility of overheating. I tend to use "50%" or less. The food cooks quite slowly in these settings. I know we have been trained to expect the food from a microwave to be heated very quickly - oh well!

  5. When you use a microwave at a low "power" setting (really, just shorter bursts of the full power of the microwave), the food should cook no more quickly than in a conventional (infrared) oven. Most of us use a microwave to heat faster - this is the problem. However, if you do use the "lower power" setting on your microwave, it will consume less energy compared to your thermal oven.

Some people are concerned that microwaves disrupt the structure of water. I will research this but find it hard to believe. My initial studies indicate it is the intensity of the heating - not the type of light energy.

Both infrared and microwave light (energy) come from God and are natural parts of the electromagnetic spectrum that hit the Earth. Can the lower-energy one really be harmful compared to the higher-energy one?

Answer: The dose makes the poison - so intensity matters - and YOU have control over this (at least to some extent).


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