Microwaving Bottles: Is It Safe?

Is microwaving a bottle to warm it up risky? And if so, what are those risks?
Are some bottles more “microwaveable” than others?
How can you safely warm up your baby's bottle without using a microwave, and without putting your child at risk?

Young parents ask themselves all of these questions. So we felt it was important to address this topic and help you get a clearer picture! 😉

Baby bottle in the microwave: a risk of micro and nanoplastic particles
Nutrient destruction: this side effect of microwaving…
Which bottles are “safe” for microwaving?
2 alternatives to warming a bottle without your microwave!
- Electric bottle warmer
- Double boiler (Bain-marie)
In summary

Baby bottle in the microwave: a risk of micro and nanoplastic particles

Of course, this only applies if the bottle is made of plastic. This material, when exposed to heat, tends to release microscopic particles that are invisible to the naked eye. These particles can then mix into your baby’s milk.

Because they produce no smell, cannot be seen, and their tiny size doesn’t change the taste of the milk, they are undetectable. 🐱‍👤Yet, there are actually millions of these particles passing into your child’s body during feeding! Plastic bottles can release microparticles even when heated using a double boiler (bain-marie) or bottle warmer.

Remember, these fine particles are considered artificial endocrine disruptors that may affect a child’s endocrine system by adulthood.

Among these plasticizers, Bisphenol A (BPA), and Phthalates have been progressively banned from manufacturing processes according to very strict regulations, including a law passed in France in 2015 prohibiting their use, and being classified as substances of very high concern (SVHC) in 2017.

However, this component was replaced with Bisphenol S (BPS), which apparently has very similar properties.

Nutrient destruction: this side effect of microwaving…

Putting your baby's bottle in the microwave presents another issue: the destruction of nutrients, vitamins, and essential minerals found in milk. Some parents, for this reason, choose to heat only the water first and add the powdered infant formula afterward. 🍼

Obviously, this solution is not possible for parents who have chosen to pump and bottle-feed breast milk, since breast milk, once thawed, doesn't require any extra preparation and must be reheated before being offered to baby!

Which bottles are “safe” for microwaving?

heat or not a baby bottle in the microwave

Not all materials break down or release micro and nanoparticles. Fortunately! You can get microwaveable bottles, such as those made from glass or silicone.

Note that this latter material has the advantage of not breaking when dropped. Since a baby does not yet have precise dexterity, using an unbreakable bottle is often both a time and money saver!

2 alternatives to warming a bottle without your microwave

Heating a bottle in the microwave has other disadvantages, such as uneven heating!

Some areas can end up hotter than others. Even if you mix the milk well, it won’t be enough to cool down the container itself, which can become almost scalding when microwaved, while the milk inside might be barely lukewarm…

This oddity is actually quite simple to explain: a microwave’s action is not continuous. Unlike a conventional heat source which heats steadily, a microwave oven uses electromagnetic waves to stimulate the molecules in the food. This creates molecular motion, thereby generating heat.

However, since these waves are emitted intermittently, the energy is not distributed evenly in the food! Certain spots can absorb more energy than others.

So, we recommend that you heat the bottle using one of these two alternative methods:

Electric bottle warmer

Invest in an electric bottle warmer or a water warmer specifically designed for heating bottles. These devices are designed to heat milk evenly. Just follow the manufacturer's instructions to ensure safe and effective use.

Always test the temperature of the milk before giving the bottle to your baby to avoid any risk of burns.

Did you know?

The Élhée adaptor was designed to allow moms to express, store, and warm their milk directly in the Élhée bottle.

This adaptor screws onto the BibRonds and Élhée Bubble training cups to make them compatible with Philips Avent and Medela breast pumps, as well as with several brands of portable bottle warmers (Munchkin, Mini Cupid, Tommee Tippee, Izybaby)!

Double boiler (Bain-marie)

Use the traditional double boiler method. Fill a saucepan with water and heat it up (don’t let it boil). Then place the bottle in the water, making sure it is well immersed, with no risk of tipping over.

The hot water will slowly transfer heat to the bottle more evenly than the microwave. Be sure to stir the milk regularly to ensure an even temperature.

In summary

Warming a baby bottle in the microwave may carry certain risks, which is why many experts recommend safer alternatives.

As mentioned above, microwave heating is not always even, which can result in hot and cold spots in the bottle’s milk. This may pose a risk of burns for your baby.

Some bottles may release harmful substances when microwaved. If the bottle is made from plastic materials, the risk is especially high, and over the years the child’s endocrine system can be affected.

Glass and silicone bottles are considered to not present this problem. Silicone, however, has the added advantage of not breaking if your baby drops it.

Finally, microwaving a bottle leads to nutrient degradation in breast milk. This is somewhat unfair and paradoxical, as breast milk naturally contains everything an infant needs for proper development!