Know Your Microwave Oven

The household microwave oven has been popular due its efficiency & convenience; however, controversial at the same time!

A lab grade microwave (μW) oven has revolutionized chemical synthesis.

A consumer grade μW oven is arguably one of the safest, convenient, fastest heating/reheating household appliances available till date.

There is insufficient scientific evidence that μW might be harmful. μW has low energy (large wavelength, only being shorter than radiowave (RW) when compared to the other waves like IR, UV, X-ray, gamma-ray, cosmic ray); and therefore, low penetration power.

I have been regularly using μW ovens for 22+ years and have not damaged a single device. I can cook/reheat basically anything (including coffee, dal, rice, noodles, pasta, omelet, chicken) using μW.

However, many customers face challenges using it as reading instructions provided by the manufacturers are a little too much difficult for many of us.

Some basics is supposed to be learned before using a μW oven. The goal of this post is to make you gain confidence on the μW ovens if you don't have it already.

Frequently asked questions (FAQs):

#1 How do I know my container (bowl/cup/plate/whatever) is microwave safe?

Answer. If you see a microwave safe icon/description typically at the bottom of the container (like the pictograms on the image provided below; the image on your container may be a bit different but close to one of these), it's μW compatible (wavy lines indicate μW). It means no damage to the container (no cracking, twisting, melting, collapsing, creating spark, catching fire, and/or exploding) and no releasing of the (harmful) container chemicals on to the food and has almost nothing to do with the safety of the μW oven itself although the oven stays protected with such containers. If a container material is transparent to μW, it allows μW to pass through without significantly absorbing/reflecting them. For safety assurance, some of these icons were generated by ISO (international organization for standardization; IEC 60417 - 5615).

#2 Which materials are good to go to a microwave oven?

Answer. Heat-resistant glass/ceramic/plastic/paper bowls/cups/plates/covers. The plastic grades are not quite followed in India or many other countries (although I observe a little change now) and most people are not aware of these grades. A grade 7 plastic is okay for use with μW. These are free of chemicals like BPA (Bisphenol A) that have a tendency to leach when heated. An alloy metal like stainless steel (SS) wrapped by a proper plastic (as shown in the image) is fine as well since these are specifically designed to be μW compatible.

Click/tap to enlarge the image

#3 Which materials are strictly NO to a microwave oven?

Answer. Any metal including (but NOT limited to) aluminum (foil)/SS/copper/silver or metallic accents/decorations. Cheap polybags like the ones provided by the grocery stores or the street vendors. Newspapers or recycled papers (paper towels/napkins). Old, damaged or cracked utensils. Whole eggs with shells or sealer containers.

#4 Which ones should be avoided?

Answer. Styrofoam boxes unless declared microwave safe. Any plastic is prone to leaching at higher temperatures and on repeated uses in practice. The proof is stains and hair cracks/cracks if used for a prolonged period. Many takeaway/parcel containers are claimed to be microwave safe nowadays; so, I don't see a problem in 'one-time' heating unless the claim is false. Thicker and sturdier μW safe paper containers are unsuitable for extended cooking times or high-power settings. If a container is getting too hot as compared to the food in it, it may NOT be microwave safe. Microwave a container with water only to test this. Some containers are microwave safe but their lids are NOT. Look for the symbols/descriptions ALWAYS!

#5 Anything else I should be aware of?

Answer. A μW oven heats the food mainly by heating water in it; so, make sure that the food has enough water/moisture content.

Avoid uneven heating. For instance, if the total heating time is 2 min, stop the μW oven after one minute, stir the food and restart the μW oven. To help uniform heating, most μW ovens nowadays have a rotating glass plate.

Avoid overcooking; else, the food may spatter (and/or burn/become dry/rubbery/nutritionless/tasteless). You may consider using a food-grade dome-shaped plastic lid with a few built-in holes (for venting) to reduce spatter and uneven heating. To avoid overcooking, watch for standing time (or power levels if your μW has this feature), too as the residual heat after the μW timer stops continues heating foods!

As long as the oven door is closed, your microwave consumes negligible power when it is not operating; so, there is no need to turn it off.

Enjoy your food using a microwave oven with safety, convenience and speed.

Disclaimer: This post is written to promote learning and may be used as a guideline. Please follow the safety measures and prevent damage at your own discretion.

Questions❓ Let Chemaficionado know in the comments below or at mychemistryhomework@gmail.com❗

References:

(1)    Iso.org. https://www.iso.org/obp/ui#iec:grs:60417:5615.
(2)    Wikipedia Contributors. Microwave oven. Wikipedia. https://en.wikipedia.org/wiki/Microwave_oven.