Nowadays, the common materials used for containing and packaging food items include glass, plastic, paper, ceramic and metal.
However, not all of these materials are suitable for microwave cooking. Some of these materials have elements or coatings that are unstable at higher temperatures and can melt or transfer toxic substances into food during microwaving.
As such, it is important to know the microwave status of any material before putting it in the oven. This will help prevent any chemical migration into food or a possible microwave hazard.
In this article, our focus will be on wax paper and its status in the microwave. We’ll also be providing a list of everyday materials that are safe to use in the microwave and those that aren’t safe to use.
In the end, you’ll also learn how to test any container around the house to find out whether it’s safe to use in the microwave or not.
Can you microwave wax paper?
Wax paper is safe to put in the microwave provided you’re not using it to wrap foods that are extremely high in fat and oil contents.
Wax paper is generally transparent to microwave radiation because its particles cannot absorb it. As a result, it doesn’t heat up directly from the radiation but rather from food sources that have been heated by the radiation.
Some foods that are high in fat and oil can easily reach temperatures above 200°F, which can easily melt the coating on wax paper and even cause ignition of the remaining paper substrate.
Here’s why wax paper is transparent to microwave radiation
The way microwave ovens work is by emitting low energy microwave radiation that is easily absorbed by some molecules in food and converted to heat for cooking.
Microwave radiation generally makes molecules to rotate, so any molecule that is able to absorb it’s energy will rotate and collide with other neighboring molecules (friction) to cause heat.
Water, fats, oils, sugar and salt are typical examples of substances in food that can absorb microwave radiation and convert its energy to heat.
They are able to do so because their molecules fulfill the necessary criteria for microwave absorption in ovens i.e [1] The energy of the microwave radiation exactly matches one of the rotational and vibrational energies of their molecules [2] They have the means to interact with the microwave radiation to absorb it’s energy and produce heat.
For wax paper, most of its particles do not satisfy the microwave absorption criteria [1] [2], so the paper as a whole, appears transparent to the microwave radiation and pass it through with little to no obstruction.
Other materials that also appear transparent to microwave radiation include; microwave air, ice, parchment paper, glass, ceramics, plastics and paper towels. Some of these substances form the basis for the manufacture of microwave safe materials.
Papers, ceramics and other materials employed as food containers or covers in microwave ovens do not get heated directly by the microwave radiation but rather from food sources that have been heated by the microwave radiation.
Therefore, only food and not microwave radiation can actually heat a wax paper to the point where it disintegrates i.e. melting of the wax coating.
But this seldom happens with water based foods since they hardly ever exceed 212°F on their surface. The reason is due to the evaporative cooling of their surface by the cold air in the cavity.
Another thing is the significant moisture accumulation on the surface of the food, which reduced the surface temperature of the food, as well as wet the interior of the wax paper and make it difficult to reach temperatures high enough to trigger any melting of the wax.
As for food items that are extremely high in fatty tissues and oil, even though these natural occurrences are present as a check mechanism, their surface temperatures can still easily surpass 170°F, which is significant enough to melt the wax coating on the paper.
Burnt foods can also raise the temperature of wax paper past its melting point and can even cause instant smoking or burning of the paper. So make sure you never leave food items (covered with wax paper) to the point where they begin to burn in the microwave!
Can wax paper migrate any toxic substance into food during microwaving?
Wax paper is generally made in two variants. The bleached and the unbleached.
If the bleached variant derives its gleaming white appearance from an industrial bleaching process that involves chlorine, chances are, that trace amounts of toxic dioxins created as effluents during the bleaching process have persisted into the final product and can therefore migrate into food during cooking.
According to this old fact sheet and this case study, the amounts of dioxins transferred into food from the chlorine bleached papers are insignificant and their health effects are negligible.
However, the World Health Organization, described dioxins as very persistent and highly toxic chemicals, and also mentioned that these chemicals can cling onto fatty tissues in the body for a period of 7-11 years.
This may imply that the very small amounts of dioxins deposits into food during cooking can potentially accumulate to toxic levels in the body over time and begin to present their health risk to people.
It’s better to err on the side of caution and do away with all chlorine bleached products for the present and future safety of one’s health and the environment.
You can read more on dioxins from this report by the World Health Organization.
Is the wax coating on wax paper harmful?
No it’s not. The wax coating on wax paper is made from food grade wax (soy or paraffin) which means that it’s completely safe when ingested.
The only caveat to the “wax paper migrating into food” thing is the funny taste that it imparts to whatever it is that you’re cooking. So whether it’s a sweet, savory or spice based treat, wax paper can easily tamper with the flavors and render any notes awkward!
Why do Fats and oils reach higher temperatures and melt wax coating?
It’s because of their lower specific heat capacity. This allows them to reach higher temperatures compared to other substances for the same amount of heat generated.
What are the safety tips for using wax paper in the microwave?
Generally speaking, wax paper is most safe when employed as a lid to prevent microwave mess. It hardly makes any contact with food so the risks of melting or burning is greatly reduced.
Moreover, this is how most brands would expect you to use their wax paper! Not by popping them in the oven or wrapping them around high fat contents at microwave HIGH!
But that doesn’t mean wax paper cannot be used to wrap foods for microwave cooking. It just needs to wrap the right kind of food for the right kind of situation.
Water based food like steak, fruits and garlic, at average microwaving conditions, won’t heat up a wax paper to the point where the wax coating begins to melt off. Foods with normal amount of fats or oils would also be fine to wrap in wax paper.
But foods with very high amounts of fats, oils, or salt can easily melt the wax coating on wax paper and transfer it into the food.
A perfect substitute for this scenario would be parchment paper since it has undergone tough treatments and processes and is thus easily able to withstand temperatures upto 450°F. (That’s nearly the cooking temperature for high heat turkey!).
Secondly, make sure to always purchase wax paper from a reliable brand. This will ensure that you’re wrapping the right kind of quality over your cheese or potatoes.
Lastly, avoid using wax paper for too long in the microwave. The wax can eventually melt off. In these situations, it’s best to stick with parchment paper or microwaveable lids.
What to use wax paper for in a microwave oven?
Use wax paper for the following in a microwave oven.
- Reheat leftovers: Place the wax paper over a microwave-safe container to prevent contamination and splatter of food as they cook. This would ease up cleaning by a mileage!
- Use wax paper as a pouch for cooking foods such as salmon, potato, corn, garlic, vegetables, scrambled eggs, banana etc.
- Use wax paper as a lid for cooking in the microwave. This ensures even heating and therefore cooking.
- Use wax paper as a plate liner when cooking greasy foods such as bacon. Be careful though as this is one food item that can easily melt the wax coating on wax paper.
- Use wax paper as a pan liner for baking cakes and bread in the microwave oven.
- Cover foods meant to be defrosted in the microwave oven with a sheet of wax paper to ensure even heating.
What other things can you put in the microwave oven?
Here are everyday materials that can be used in the microwave oven.
- Any utensil, container or wrap labelled safe for microwave use.
- Parchment paper.
- Glass-ceramic material.
- Baking mats.
- Oven cooking bags.
- Glass, ceramics and plastics containers and wraps with a clear microwave safe label.
- White paper plates, towels, napkins, bags and bowls.
- Styrofoam; Do not use Styrofoam for fatty, oily foods, soups, or noodles.
- Pyrex.
- Straw or wooden basket.
What materials are not safe to put in the microwave oven?
Never use the following items in a microwave oven.
- Any utensil, container or wrap labelled not safe for microwave use.
- Thin plastic storage bags.
- Brown paper bags.
- Plastic grocery bags.
- Newspapers.
- Aluminum foil: they are only safe to use in small amounts, like when shielding small areas of poultry food to prevent over cooking.
- Metal pans.
- Recycled materials.
- One time food containers i.e. yogurt cartons and margarine tubs.
- Foam insulated cups, bowls, plates or trays.
- Anything with metallic rim or handles.
- Metal twist ties.
- Warped or melted containers.
How to tell if a container is safe to use in the microwave oven
Use this test to know if a container is safe to use in the microwave oven.
- Pour 1 cup of water in a glass cup.
- Place the glass cup along with the container you want to test side by side in the microwave oven.
- Heat at any setting for 1 minute.
- If the test container ends up warm or hot, do not use it.
