Introduction: How to Heat Baby Milk/formula in the Microwave.

Picture of How to Heat Baby Milk/formula in the Microwave.

Everybody knows you're not supposed to heat breast milk or formula in the microwave. Why not? The top two reasons usually cited are 1) it kills nutrients, which is scientifically unfounded, unless you're leaving it in there for 20 minutes, or 2) it creates hot spots, which can scald baby, which would be slightly plausible if we weren't talking about a liquid, which is going to have convection currents and is going to be thoroughly mixed long before it gets to baby's mouth.

No, the only real reason not to heat milk in the microwave is also the best one: because if you do, your baby's momma will kill you. She read all those reports on the internets and she doesn't believe your scientific mumbo-jumbo about upwelling for a minute.

So what's Daddy to do when baby is crying for food and Mommy's out at yoga? Just running hot water from the tap over the bottle takes forever and wastes a lot of water. It takes a while for the water to get hot and then most of the heat is just running down the drain.

Step 1: Heat Some Water in a Measuring Cup.

Picture of Heat Some Water in a Measuring Cup.

Grab the nearest Pyrex measuring cup. Put a couple ounces of tap water into it. Use the hot tap but don't wait for it to actually get hot--junior is hungry and time's a' wastin'! Stick the cup in the microwave for 1-2 minutes. You don't need a lot of water, because the bottle is going to displace a lot. You don't need a lot of time because, well, this is what microwaves are made for!

Step 2: Insert Bottle.

Picture of Insert Bottle.

Stick the bottle in the cup of hot water. Swirl it around. After a few minutes, check the temperature by doing that thing they do on TV and in the movies, which you always wanted to do in real life: squirt some milk on your wrist to see how warm it is.

Step 3: Enjoy!

Picture of Enjoy!

Serve warm. Makes 1 serving.


YapH1 (author)2016-06-10

Thank you author..! I couldn't find any article with proper scientific backing for why microwave cannot be used on breast milk either..! but apparently, my wife could flash out a pamphlet from the hospital advises against microwave (yes, lost that one, sigh). My thinking: maybe, microwave damages the immune cells found in beast milk (due to heat spots) believed to be helpful to babies. I think there are many factors in breast milk which are not yet understood (which is why formula milk cannot give babies the same benefits as breast milk - we don't know how to replicate artificial breast milk exactly)

mstone9 (author)2011-09-10

No, the reason for not heating formula in a microwave is because research shows that it can lead to increased risk of severe ear infections in toddlers and infants.

worried123 (author)mstone92016-01-22

what if i mix the formula in 100 degree and let it cool down?

mstone9 (author)2011-09-10

I had 5 sets of ear infections with tubes followed by equilibrium imbalance in the inner ear, when I was little. I am pretty sure that heating formula in a microwave helped that happen.

sgernant (author)mstone92011-10-02

i'm pretty sure you're totally wrong.

jdrago1 (author)sgernant2016-01-16

I'm pretty sure, you are totally correct . The toaster gave me cancer. lol

kelseymh (author)2008-10-27

Before reading my comments below, let me first say this is a good recommendation! Whether you believe in the evils of microwaves or not, this is surely an appropriate way to work around someone else's concerns without dismissing or ignoring them. Having said that...

For one of the "reasons" not to microwave formula, you cited, "it creates hot spots," and debunked with and argument about convection currents in liquid. While quite true in principle, it doesn't necessarily apply to this case.

Microwaving anything will induce hotspots, just because of the way microwaves are generated and bounce around inside the enclosure.
You are (hopefully!) not heating the formula to very much above body temperature (not more than ~100-105F) or you can scald the baby's mouth. In such a case, the temperature differences between hot and cold regions are less likely to induce good convective flow, and so the hotspots can persist for a substantial time. Also, formula is thicker than water, which reduces the development of convection on short timescales (viscous inertia); you can verify this by heating a bowl of canned cream-style soup in a Pyrex cup.

For both reasons, rather than rely on convection, you really do need to manually mix the heated formula, and check the temperature after mixing. A good approach is to heat in very short steps (5-10 seconds at a time), mixing and checking at each step. This is sufficiently slow and awkward, especially when the young one is getting impaTIENT!!! :-O, that it is really not worth the hassle.

crash28 (author)kelseymh2012-07-21

I have a bottle warmer that you plug into the wall .. it has water in it.. when the light goes off I check the formula.... swilr it in the botlte then check again and it's usually always perfect then it warmed and ready AND fully nutritious for our precious one :D thakews about 3 mins.. don't see what all this fuss is about.....

kelseymh (author)crash282012-07-21

Right! That is a proper conduction warmer (it's basically just a double boiler). That is absolutely the best method.

The point of this posting is that microwave ovens do not heat _anything_ uniformly. It's not a big deal for adults, who have (a) better tolerance and take less damage from overly-hot food, and (b) have learned what to do if they eat something too hot. Infants, as you well know, don't have either those skills or that tissue protection.

scrappysue (author)2008-03-31

The last time someone heated a babys bottle in my microwave, the whole thing exploded and blew the door off, very frightening for all concerned since the microwave was on top of the fridge, ie head height, and it was lucky no one was seriously hurt. The explainantion most people have is that the bottles teat got blocked.

crash28 (author)scrappysue2012-07-21

the bottle had the nipple on it in the microwave??? no wonder

jynnavyveart (author)2008-04-20

I agree with the microwave thing, just because it's a funny thing for food to get hot without fiance and I just recently had a baby this winter, and because of chemo and a c-section, I was unable to produce enough milk to breastfeed for more than 3, unfortunately, we had to start her on formula. In the middle of winter when she wakes up hungry, it is hard to wait until the bottle is warm from warming it in the mug(as we started out doing). We then had an epiphany! We live in a big old house with huge square furnace vents on the floor, one being next to her bed. We keep the jugs of Nursery Water sitting on top of the vent, so it's always about 68 degrees when we pour it into the bottle for feeding. No microwave. No waiting. It's always the perfect temp and it makes our lives a whole lot easier when she is demanding the food:) At night, I make up 3-4 bottles with the nursery water already in it (no formula) and set them on top of the furnace they're ready to go when we need them!

crash28 (author)jynnavyveart2012-07-21

BRILLIANT!! and convenient that your house is built that way :D

siriusbarras (author)2009-04-28

What you say is reasonable. But I also find this (without check the source):

Do not heat milk in a microwave oven

Heating or thawing human milk by microwave causes a decrease in the level of anti infective factors in the milk, even when low temperatures (20-53¡C) are used (Pediatrics, 1992; 89: 667-9).

In one study, conducted at Stanford University in California, microwaving at higher than 72¡C was found to cause a considerable decrease in all the tested anti infective factors. The Stanford researchers strongly rejected the use of microwaving, even at low temperatures, of human milk in hospitals.Another study, carried out in Vienna, found that microwave cooking induced high rates of change in food proteins that were not observed after conventional cooking. D-proline and cis-D-hydroxyproline were found in significant quantities in microwave heated infant milk formulas, whereas only L-proline is normally found in biological material.

(L stands for laevo-rotary, D for dextro-rotary, referring to the direction electrons rotate in their plane of optical polarisation.)

Lubec and his colleagues warned that "the conversion of trans to cis forms could be hazardous because when cis-amino acids are incorporated into peptides and proteins instead of their trans isomers, this can lead to structural, functional, and immunological changes" (Lancet, 1989; 9: 1392-3).

Other research has also found that microwaving infant formula can produce molecular changes in the amino acids in milk proteins, causing toxicity or affecting the nutritional value of the milk formula. Nevertheless, the quantity of proteins changed was very small (J Am Coll Nutr, 1994; 13: 209-10).

crash28 (author)siriusbarras2012-07-21

thats for all the hard facts!!!! GREAT info is so refreshing ;)

kactv02 (author)2009-04-30

how bout if you heat the water first in the microwave then add the powdered milk after? is that safe?

crash28 (author)kactv022012-07-21

I beleive so... I don't see why not.. as long as its in a glass bottle ;)

F1X0R (author)2008-04-05

well James, don't give you're Kids/plants remote control cars, play walkie talkies, mobile phones which all use the same part of the electromagnetic spectrum as microwaves, I've set up an actual experimental design to test you're theory (more scientific than anecdotal evidence) , I brought two Peace lilies, feeding them the same amount of water, one i am giving one tap water, and the other the same tap water but put in the microwave on high for 3 minutes FYI I used a 800watt microwave, we are 4 days into the trial now, and no notable difference between the two, after this week i shall next week give the one thats been having regular tap water the microwave water and visa versa, just to see what happens (nothing i suspect)

crash28 (author)F1X0R2012-07-21

Interesting approach to testing the affects of nuking a source of nutrition.... IF I'm not mistaken a plant gets it's nutrition from mostly the soil that it grows in ...... so nuking the water I don't suspect that you WOULD see a different in the growth of your peace lilies... maybe nuking the soil you plant them in would show different results......just saying :)

island_hackster (author)F1X0R2009-05-10

four days? not much time. Now you're gonna switch. of course you won't see results.

F1X0R (author)F1X0R2008-04-05

are you sure you should have given it only a glass a week by the way ?

drougvie (author)2011-10-22

I just use water from the kettle into big mug along with bottle .... few minutes later check on my arm .... ta da done, and i get a cup of coffee at the same time :)
cute kid :)

tvm777 (author)2011-02-05

easy and truly :D

wocket (author)2010-09-27

we always did a 10 sec burst in a glass bottle to warm it, added the milk powder (after 10 months i was unable to breastfeed, long story) and shake vigorously. 10 secs was enough to gently warm the formula but not make it hot.

joejoerowley (author)2008-03-29

Cool! Very, very Cute Baby! :)

J-Five (author)joejoerowley2010-06-21

I agree the baby is so adorable!!!

lowbike1 (author)2010-02-12

yes we had one birth child and then we adopted, perhaps I should have clarified

HuntingWabbits (author)2009-08-31

Or you could just keep a thermos of hot water and a bottle of clean water, and use those to mix said baby drink.

got2bskilled (author)2009-07-23

Good points here. The only reason why I don't use the microwave is the effect on the plastic itself. My daughter could never get rid of Thrush- so I boiled the bottles or nuked the bottle to kill the yeast. Long story short- the doc said plastic bottles become porous when heated and it gives bad things more places to hide. Then shortly all the media about nuked plastic came about. I am pregnant again- THIS TIME I AM USING GLASS! :-) But the nuking water in pyrex is genius!

ibkuhl (author)2009-05-31

It is just like everything else, if you are dumb about it then bad things are going to happen. If you leave anything in the microwave too long, it will lose nutrients, flavor, and be very hot... duh?
The CDC says: "Avoid using a microwave oven to thaw or heat bottles of breast milk" They do not say "don't do it"

zena124 (author)2009-05-11

As a mom of three, i've done this from time to time. In fact, i've never even used the cup of water, just put the bottle in. It doesn't take much sense to know to shake it well before feeding. My boys still have their wits about them, and are doing well, so I don't think i've damaged them *too* badly by throwing the bottle in microwave!

gracielynn (author)2009-05-06

I had to chuckle at this.. I guess if you were born After microwaves.. you wouldn't know , but we always warmed water on the stove. removed the pan from the burner & set the Glass bottle into it .. :-) I'm an oldie I guess .

unseen wombat (author)2009-05-01

I completely agree with the premise of this instructable. It's total baloney that you can't heat the milk in the microwave. I'm lucky that my baby's mother is reasonable enough to realize this and we both warm it up that way. :)

James (pseudo-geek) (author)2008-03-31

If your first paragraph is true, try this. put a glass of water in a microwave for 3 minutes, and water a potted plant with it for a week. I promise you that plant will die. and don't anyone dare anyone spout off about how it was "already dying" because it was perfectly healthy.

My plant didn't die. Then again, it's also a cactus; does that make a difference? :P

I will NEVER feed my children microwaved ANYTHING. And I'm dead serious. My children will breastfeed, and never be given formula.

And what happens if the woman you settle down with with doesn't feel comfortable breastfeeding, or can't produce enough milk? Life doesn't always go according to plan.

my son was adopted, so we fed him formula, my wife tried to breastfeed him but not enough milk came in.... are we bad parents? microwaving food is safe, just dont do it in plastic containers

"But Dad, I'm fifteen years old! All I want is to microwave some pizza!" "No son of mine is eating microwaved food!" :P

Wait...why were you microwaving your plant's water anyway? If it was an experiment to see if microwaved water is bad for you, you should definitely use a control for a more definitive answer.

Microwaves do not chemically alter food items. They heat food using non-ionizing radiation. This means that it won't be cleaving your DNA or irradiating your food. In fact, pan or grill heating things can produce far more toxic substances by creating charred food. Charred food material contains all sorts of carcinogenic molecules (PAH's, PhIP, etc) that can mimic the effects of ionizing radiation. Microwaving food avoids all of this. About the most dangerous part of microwaving food is the occasional super heating of liquids like coffee (causing a boiling eruption that I find very amusing), potatoes, eggs, etc. I can't explain why your plant died but I can safely say that it wasn't because you microwaved the water. All microwaves do to H2O is cause a di-pole shift when microwaves are absorbed and infrared radiation (the kind that heats food and the reason we sit facing the fire during cold winter nights) is then released. Nothing more nothing can actually reduce the dissolved gas in water but this also happens when you heat water on the stove. No difference there.

That's because you're giving a living plant hot, or warm (room tempurature?) water.

Plants get rain water. Rain comes from the sky. The sky is very cold. I know, because I spend allot of time up there. For every one thousand feet of sky, the temperature drops by about two degrees Celsius. Except the first few thousand feet of sky. Those first few thousand feet of sky are much warmer than the rest of the sky, because it is heated by the ground. So after the first few thousand feet of sky, there is a more significant temperature drop. Also, the sky is blue.

actually I've been giving my Lavender plants warm water and they've been growing nicely.

Starbrite (author)2008-05-25

I remember reading somewhere to save some time make a lot of formula and put it in the fridge. at one point I did this but it just wouldn't heat up for the longest time. I always used warm tap water(of course clean tap water) with her powder formula and my daughter drank it all up. No one said the formula has to be really warm. Say your at an appt. and they are hungry if you have a bottle of room temperature water and the formula. mix it and serve. So yeah, thats a good idea for the bottle. when my daughter demanded for her milk to be warmer I bought a warmer. it worked OK but it was a bit confusing. Cute baby!

krista.kellar (author)2008-04-08

This is what I do all the time. I dont know why more people didn't think of this as an alternative to the "dont heat up dangerous plastic" panic.

I'm a baby's mama, two times over... and I never panic. Its the baby's daddy that reads digg feeds and pitches a rockstar fit!! 'Neah nah nah nah nah!'

guerin (author)2008-03-31

I have never heard of these claims in relation to heating formula in a microwave and as such I have been doing so since my daughter was born. I just check that the milk is not overly hot (it is only just not cold). Are there other irrational things I should worry myself about?

SpinWard (author)2008-03-31

What a cutie! I agree with the first paragraph. Why not? At 2am and he's screaming because he's hungry, I didn't care if it was mumbo-jumbo. I made a bottle of formula and stick it in the fridge. At 2am, microwaved that bottle without the top, mixed it up good. Now he's a healthy, fast 3 year old!

loqk (author)2008-03-31

i think one of the greatest problems is with frozen milk. frozen milk won't form convection currents until it becomes mostly liquid. while still mostly solid, the liquid may defrost at hotspots and then overheat. the main problem with overheating is denaturing the protein. just by getting the milk a little too hot in a small area you can break the proteins that make up part of the milk. i believe most of the parts that carry immune protection will be destroyed in this way. in the same way, you can destroy some venoms by heating, but if you have already been bitten, you will probably cook yourself too if you try heating the bite. protecting the milk with the layer of water is great and you can claim you got the idea from a nuclear reactor :-)

Aerospaceman (author)2008-03-30

Microwave the water, NOT formula, for about ten to twelve seconds was good for general use at home to warm the the formula like the above example. You can also do it like Solo says, that works too. Remember that all microwaves heat at different levels so please check to ensure nothing can scold your baby.

joemonkey (author)2008-03-30

what is the baby's name?

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