Baby formula is expensive AF. Even if you’re getting it in bulk, with coupons, you’re having to still justify the cost to feed formula to your baby (especially when you might be seeing or hearing everyone around you saying “breast milk is free!” I experienced this early as a first time mom and even though I struggled with breastfeeding early on there was a part of me that was resistant to wasting any formula.
This is why I did the research so you wouldn’t have to about whether or not it’s safe to reheat formula.
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Is it Safe to Reheat Baby Formula?
It’s not cut and dry yes you can reheat formula.
It’s also not necessary to reheat formula for your baby’s bottle. In fact, offering your baby cold or room temperature formula is perfectly safe according to the CDC.
Formula and Breastmilk can offer similar convenient and nutritional benefits necessary for the healthy development of your baby.
However, how we handle infant formula is a bit different from breast milk, and important for every fearless formula feeder to know.
Bottom line, you just need to follow certain guidelines.
Before we can get into when it is safe to reheat formula, let’s quickly discuss the different reasons why you might consider doing this.
When Is it Safe to Reheat Formula: For Premade Formula Bottles
If you’re making a batch of prepared formula for feeding over the next 24 hours, it is safe to reheat the formula for a later feeding.
You’ll want to follow guidelines on the bottle as far as proper storage and handling to avoid exposing your baby to food-born illnesses.
The CDC generally advises against reusing previously used formula. (More on that below!)
Never attempt to reheat thawed frozen breast milk or previously prepared refrigerated packaged baby formula in a microwave or boiling water.
When Is it Safe to Reheat Formula: Store-Bought Liquid Formula
I was always very stressed out about this type of formula. Because once you open it, you gotta use the entire bottle within 24 hours. Sometimes this was possible if my baby was going through a growth spurt, but often I’d find myself dumping at least a third of the bottle for fears of bacteria growth or exposing my baby to unsafe formula.
However, if you’re using the premade liquid formula, reheating it is safe to do so, as long as you are bringing the formula to a temperature that is safe for your baby. I.e. we don’t want to microwave formula.
My favorite way to reheat formula was to actually microwave a cup of water for about 30seconds to 1 minute (or if you have an electric kettle that works too. Then I’d pour the hot water into a large cup or bowl.
Then I’d pour the cold formula into a baby bottle, place the baby formula bottles into the cup/bowl and wait maybe about 5 minutes for the formula to come to a temperature that my baby would like – which was usually room temp.
The type of water you use is really dependent on the latest data but filtered tap water, or “safe” bottled water should be okay.
If your baby refuses to drink it at this temp, then consider using warmed filtered water to make the baby bottle.
Or a Baby Brezza machine that heats the formula to the perfect temperature.
But be careful – experts warn that scalding or boiling water can potentially kill the nutrients that are in baby formula that are essential to the development of your baby (never mind that it will take a while to cool down to be safe enough to feed to your infant).
How Many Times Can You Reheat Baby Formula: Used/Old Formula
Toss the unused formula and say adios to that formula that cannot be given to your baby safely.
If you need to warm bottles of formula you should plan to do this only once.
According to the CDC: “Throw out any infant formula that is left in the bottle after feeding your baby. The combination of infant formula and your baby’s saliva can cause bacteria to grow. Be sure to clean and sanitize the bottle before its next use.” Be sure to wash bottles between every feeding.
If you’re going to reuse baby formula, general guidelines dictate that you shouldn’t store it in the refrigerator for more than 24 hours—otherwise, harmful bacteria can form and potentially make your baby sick.
How Can you Safely Reheat Baby Formula
It’s not a good idea to warm formula in the microwave for the same reasons it’s not recommended for breastfed babies – it makes it possible for hot spots to develop in baby’s milk.
It may be cliche but be sure to test the warmed milk on the inside of your wrist (which is a delicate area that mimics the baby’s mouth) to make sure the baby’s formula is at the right temperature.
You could also consider exposing your baby to cold formula, or room temp formula. In fact, this is one of my formula feeding hacks to give your baby room temperature formula, as a way of being able to “travel” or be on the go or even in the middle of the night saving you some time to sleep by not heating up the prepared bottle.
That post also has a ton of ways to warm water on the go too, if you’ve got a picky eater…go check it out;). And side note, have you ever wondered why do formula fed babies sleep longer? I got the answer on this article!
You should also shake the container before using it again and then throw out any remaining formula that is left over after one hour of feeding.
In fact, I had a pediatrician warn me early on that if your baby is still working on a bottle of formula, toss it after an hour JUST IN CASE and make a new one with clean water and smaller quantities.
This is helpful during a growth spurt where the baby mimics the “cluster feeding”many breastfeeding moms experience and really the only time I’d make large batches of fresh formula.
This should go without saying but even if you are not reusing your formula, you should still throw away any leftover formula that is left over after a feeding
Can I Reheat Baby Formula More Than Once?
You should only reheat a single-serve container of prepared liquid formula once per day and never heat a second time if any portion goes unused.
As we’ve mentioned, this is because bacteria multiply quickly when stored at room temperature, especially after being warmed up once already earlier in the day.
How Long Can You Keep Formula?
Unopened powdered formula lasts around a year, and ready-to-eat formula lasts around three to four weeks.
Don’t store the powdered or opened ready-to-eat stuff in the fridge, because you run the risk of bacteria growing in it. pay attention to the expiration date of formula powder and be sure to follow all of the manufacturer’s instructions.
After heating and serving, get rid of anything your baby doesn’t drink within an hour. There are probably more germs in your baby’s mouth than anywhere else, so keeping old milk lying around is a bad idea.
Important: Instructions for formula preparation should be provided by the manufacturer of the product you are using and should be followed carefully.
Yes, you can reheat baby formula–but there are a few guidelines you’ll want to follow in order to do so safely.