How to Store Breast Milk (and Not Go Bust)

You know that saying: “There’s no use crying over spilled milk.” Well, it absolutely doesn’t apply if said liquid came from your own body and was inefficiently extracted by a machine that looks like a torture device (i.e., a breast pump). Still, if you are, or plan to be, a breastfeeding mom, there’s a good chance you will have to pump at some point. It isn’t the worst thing in the world, but after breastfeeding two kids and pumping at work for a combined couple of years, I can say that, on more than one occasion, I have improperly stored (or just forgot to put away) my pumped milk and discovered it was no good when I needed it...and I don’t think I have ever wept with such despair. Luckily, this crisis is easy enough to avoid if you know how to store breast milk and get into a rhythm of doing it the right way, every time. Read on for all the information you need to ensure your liquid gold never goes to waste.

Aside from a pump (here are some of our favorites), very few supplies are required to safely store breast milk for your baby. In fact, all you really need are the storage containers—glass or BPA-free plastic bottles and plastic breast milk freezer bags are all good options—and most pumps come with bottles you can pump directly into, then store when you’re done.

Bottles are bulky, though—and if you’re basically surviving on frozen pizza and waffles (just us?) you might not want breast milk to take over all the real estate in your freezer or fridge. Storage bags are extremely helpful space-savers if you’re planning on getting ahead of the game by building up a sizable freezer stash of breast milk--but just be aware that not all plastic bags are created equal. In fact, you should only use storage bags that have been specifically designed for breast milk, as these products boast a safer BPA-free guarantee than the average plastic bag and a better seal, which does a bang up job of protecting breast milk from freezer burn and (gasps) spillage.

Okay, given the shelf life of breast milk at room temperature, ‘store’ is a bit of a misnomer. That said, you might be surprised by how long that milk will stay fresh when just hanging out on the kitchen counter. The good news comes courtesy of The Office on Women’s Health: Breast milk is safe to use for up to four hours after pumping when left at room temperature—and room temperature applies to any spot that reaches up to, but not beyond, 77 degrees Fahrenheit, which is considerably warmer than most of us set our thermostat at home. Room temperature breast milk is ideal if you intend to give it to your baby within a couple of hours, because you’ll likely be able to skip the annoying reheat step (more on that below). Another reason the four hour room temperature window is a big relief? We’re sometimes sleep-deprived, always, er, human—and who hasn’t forgotten to send that stuff to the fridge once or twice?

Freshly expressed breast milk (i.e., not previously frozen) is safe to store in the refrigerator for up to four days, provided it finds its way there within the aforementioned four-hour room temperature window. If you don’t have a freezer stash, and essentially pump today what your child will drink tomorrow, the fridge is a good option because you (or your partner or child care provider) won’t have to pay the steep price of trying to make a hungry child wait for the good stuff to defrost.

To store breast milk in the fridge, simply express or pump into BPA-free bottles and tuck the milk into your refrigerator. Just be sure to date each bottle first, then place the newer bottle towards the back of the fridge, you remember to use the old stuff first. Final pro tip, per the CDC: Don’t put that breast milk in the door of your fridge—a storage spot known for temperature fluctuations that will put your milk at risk of spoiling sooner.

Breast milk might seem like a fickle thing. (I mean, bacon lasts for a full month in the fridge, and that’s meat. Four days doesn’t sound all that impressive!) Enter the freezer option. Believe it or not, the CDC says that breast milk that has been promptly stored in the freezer will taste mama-farm-fresh for six months, but be safe to feed to a baby for up to a full year. In other words, if there could possibly be an appliance that would make you want to get your pump on, it’s the freezer.

But can breast milk go from the fridge to freezer? Yep. As long as you’re in that four-day window, you can change storage locations, but the sooner the better. In fact, if you remain within the recommended time frames, you can go from room temperature to fridge, to freezer—and your baby’s milk will be just fine. The reverse is not true, however, so read on for the more stringent guidelines on how to thaw, heat and feed your child from your breast milk overstock.

So how do you use stored breast milk, ideally for something really fun like an actual date with your partner, a drink with your best friend, a solo movie night, a meditative walk through a park or even just a moment to sit in blissful silence? See below for a simple breakdown that will tell you everything you need to know so someone else can feed your baby the best milk possible.

1. Thaw

Obviously, any milk that has been frozen needs to be thawed before a baby can drink it, and though the process isn’t difficult, it is rather delicate. The best way to thaw frozen milk is in the fridge overnight, and If you have the wherewithal to think ahead every night you deserve serious praise. Forgot to pull that freezer milk for the next day? Don’t despair. It can be thawed fairly quickly (10-20 minutes, depending on the number of ounces) and completely safe in a cold water bath. Hint: This process isn’t that quick when thawing a large amount, which is another reason why you should always store breast milk in single servings.

2. Reheat (or don’t)

It is absolutely unnecessary to heat your baby’s milk...unless it is. Most babies take just fine to cold or room temperature milk, which is perfectly safe to consume. But some who are hooked on body temperature (roughly 99 degrees Fahrenheit) food might revolt. In this case, the CDC says you can spare your provider or partner the stress of a bottle strike by placing a thawed bottle or bag of breast milk in a container and running warm (not hot) water over it to take the chill off. No matter what, do not use direct heat—stove, microwave—to reheat breast milk. Mom tip: You can potentially avoid the whole hassle entirely if you decide not to reheat milk until you know for sure that your tiny tyrant requires it.

3. Do Not Refreeze

Breast milk cannot be sent back to the freezer once it has been there before. The CDC says that previously frozen milk can, however, still be consumed by your baby within two hours of thawing when left at room temperature or up to 24 hours if it has been placed in the fridge.

4. Two-hour Leftover Limit

So, your newborn was shrieking and you coulda sworn he needed milk but maybe it was just reflux..and now you’ve wasted two precious ounces of breastmilk. Nah. Even if your child contaminated the bottle with a touch-and-go feeding, you can still stick it in the fridge where it will stay fresh for another two hours—and there’s a good chance the inscrutable creature will be hungry again in that time.

That’s all you need to know, mamas. Now, may your pumping be productive, if not entirely pleasant. Read: Not for nothin’.