Physicists explain fireballs erupting from grapes in microwave oven

Proceedings of the National Academy of Sciences (2019).

A trio of researchers with McMaster, Concordia and Trent Universities has solved the mystery of why pairs of grapes ignite into fireballs when cooked together in a microwave oven. In their paper published in Proceedings of the National Academy of Sciences, Hamza Khattak, Pablo Bianucci and Aaron Slepkov claim that the fireball is not the result of heat from the outside of the grapes making its way in, but instead comes about due to hotspots that form in both grapes.

Back in 2011, impressive videos of grapes igniting in microwaves went viral on YouTube. All a person had to do was cut a in half, leaving the two halves connected by a bit of skin at the bottom, and heat them in a —within seconds, a tiny fireball would appear between them. Making things even more exciting was that nobody could explain it. Since that time, many armchair scientists have presented possible explanations—one of the more popular was the suggestion that the grapes somehow form an antenna directing the microwaves across the skin bridge. In this new effort, the physicists in Canada ran multiple tests on the grapes and other similar objects to learn the true reason for the formation of the fireball.

The tests consisted mostly of using to capture the action as the grapes were heated and running simulations. They also tested other similarly sized fruit and plastic balls filled with water.

The researchers found that the formation of the fireball was the result of a simple process. As the microwaves enter the grapes, hot spots form in both pieces at the points where they are closest to one another due to a bond between them. As the hot spots grow hotter, surrounding electrolytes become supercharged, resulting in the formation of a burst of in the form of a small fireball.

The researchers note that the same effect could be produced using similarly sized fruit or water-filled balls. They also found that it is not necessary to maintain any sort of physical connection between the two pieces—all that is required is that they be no more than three millimeters apart.

Studies Show Microwaves Drastically Reduce Nutrients In Food

I can remember the days growing up in the 1950′s and 1960′s, when we prepared foods without a microwave oven. Water was boiled on the stove. Chicken was baked in an oven. Vegetables were steamed, baked, or sautéed. Food was whole and fresh. Even a TV dinner was baked in the oven, which took about 15 minutes to warm. And then, modern science and technology brought us the microwave oven that could heat food rapidly, from 30 seconds to a couple of minutes.

The industry has claimed that microwave cooking protects the nutrient content of foods. Somehow, in tasting foods that came out of a microwave oven, the texture was changed as was the flavor. Foods cooked or reheated in microwave ovens became rubbery and lacked the savory smells and layered flavors that come from cooking foods slower and longer.

Nevertheless, people bought the convenience aspect, the speed, the simplicity of heating and eating prepared foods. The science, which has been supported by the food industry, has continued to claim the health benefits of microwave cooking. Recently, published data from reliable sources questions the health benefits of microwaved food.

Does this mean an occasional microwaved meal will be harmful? Not likely. But what about a steady diet of eating foods cooked at such a high heat? Do the sensitive compounds in food, such as amino acids, fatty acids, vitamins and phytonutrients change? It appears so. Read on to follow the scientific literature surrounding the depletion of our soil, foods, and health as a result of modern farming, food processing, microwave cooking, and not eating enough fresh, natural, uncooked, organic whole foods.

  • Three recent studies of historical food composition have shown 5-40% declines in some of the minerals in fresh produce, and another study found a similar decline in our protein sources (1)
  • A 1999 Scandinavian study of the cooking of asparagus spears found that microwaving caused a reduction in vitamins (3)
  • In a study of garlic, as little as 60 seconds of microwave heating was enough to inactivate its allinase, garlic’s principle active ingredient against cancer (5)
  • A study published in the November 2003 issue of The Journal of the Science of Food and Agriculture found that broccoli “zapped” in the microwave with a little water lost up to 97% of its beneficial antioxidants. By comparison, steamed broccoli lost 11% or fewer of its antioxidants. There were also reductions in phenolic compounds and glucosinolates, but mineral levels remained intact (6).
  • A recent Australian study showed that micro- waves cause a higher degree of “protein unfolding” than conventional heating (2)
  • Microwaving can destroy the essential disease-fighting agents in breast milk that offer protection for your baby. In 1992, Quan found that microwaved breast milk lost lysozyme activity, antibodies, and fostered the growth of more potentially pathogenic bacteria (4).

Quan stated that more damage was done to the milk by microwaving than by other methods of heating, concluding: “Microwaving appears to be contraindicated at high-temperatures, and questions regarding its safety exist even at low temperatures.”

Note: Needless to say, we do not recommend cooking food in microwave ovens, though mildly heating leftovers may not pose the same problems as discussed above. Also, microwaving fatty foods in plastic containers leads to the release of dioxins (known carcinogens) and other toxins into your food. Common microwavable foods include pizzas, chips, and popcorn. Chemicals released include polyethylene terpthalate (PET), benzene, toluene, and xylene.

Additionally, microwaving creates new compounds that are not found in humans or in nature, called radiolytic compounds. We don’t yet know what these compounds are doing to your body, but they are not health-promoting.

Eating fresh, uncooked, or minimally heated fruits and vegetables, nuts and seeds, herbs and spices are the basis of an Eating for Health™ meal plan. With whole grains and legumes, cooking them on a stove top by boiling and simmering them until tender is advised.

For flesh foods, steaming, sautéing, baking, or blending into slow cooked crock pot soups and stews is advised. Dairy products, such as raw milk cheese, from goats, cows, or sheep, are most nutrient-rich when unheated. Raw, organic cheese is best added to salads or warm grains, legumes, or vegetables without heating the dish in a high heat oven, broiler, or microwave oven.

Article Sources

1. Davis D R. (February 1, 2009). Declining fruit and vegetable nutrient composition: What is the evidence? American Society of Horticultural Science.

2. George D F, Bilek M M, and McKenzie D R. Non-thermal effects in the microwave induced unfolding of proteins observed by chaperone binding. Bioelectromagnetics 2008 May;29(4). 324-330.

3. Kidmose U and Kaack K. Acta. Agriculturae Scandinavica B1999:49(2).110-117.

4. Quan R (et al). Effects of microwave radiation on anti- infective factors in human milk. Pediatrics 89(4 part I). 667-669.

5. Song K and Milner J A. The influence of heating on the anticancer properties of garlic. Journal of Nutrition 2001;131(3S).1054S-1057S.

6. Vallejo F, Tomas-Barberan F A, and Garcia-Viguera C. Phenolic compound contents in edible parts of broccoli inflorescences after domestic cooking. Journal of the Science of Food and Agriculture (15 Oct

Haters Are Gonna Hate, Study Confirms.

Haters really are going to hate. A new study published in the Journal of Personality and Social Psychology corroborates the hip-hop and Internet truism that you just can’t win with some people. (No word yet on whether playas gonna play or ballers gonna ball, but we’ll probably find out soon. Researchers gonna research.)  


In their paper “Attitudes Without Objects,” psychologists Justin Hepler and Dolores Albarracin show that those who already hold a lot of negative views are more likely to react negatively to new stimuli. The pair asked a group of 200 men and women to evaluate how they felt about various subjects, such as camping, health care, architecture, taxidermy, crossword puzzles, and Japan. They took note of the respondents who rated many of these unconnected prompts harshly (the haters). Then, a month later, they asked everyone to weigh in again to control for the possibility that the grumps were just in a bad mood the first time.

After marking the dependably hateful haters with a scarlet H, the researchers presented participants with information about a new product: the “Monahan LPI-800 Compact 2/3-Cubic-Foot 700-Watt Microwave Oven.” This elaborately titled microwave oven does not exist (except in Jack Donaghy‘s mind), but participants didn’t know this and were given three glowing fake reviews and three dissatisfied fake reviews. While people who more or less liked taxidermy and crossword puzzles also liked the oven, the haters drenched their fake consumer surveys in haterade. They were also more likely to hate on recycling and vaccine shots. (To be fair, it’s hard to be a ray of sunshine when you’ve got the measles.)

Hepler and Albarracin write:

If individuals differ in the general tendency to like versus dislike objects, an intriguing possibility is that attitudes toward independent objects may actually be related. So someone’s attitude toward architecture may in fact tell us something about their attitude toward health care because both attitudes would be biased by a disposition to like or dislike stimuli.

In other words, although you may be as inoffensive as a Monahan LPI-800 Compact 2/3-Cubic-Foot 700-Watt Microwave Oven, some people will still think you’re the worst. I leave it to this prancing kitten to determine whether such knowledge is liberating or depressing—and to you commenters to continue providing backup for this study’s result every single day.