How to Start Building a Milk Stash

Pumped Milk StashIt is such a common question: “How do I start a freezer stash of breastmilk?”

First, if you haven’t done so already, please read “How Much Milk Do You Need in Your Stash When You Return to Work?Even if you aren’t going back to work, this is a helpful read, as you may have an impression that if you don’t have a giant freezer stash of milk that you don’t have enough milk to continue feeding, and that link above can help put that into perspective.

Once you have read that, if you do need or want to store away some milk for going back to work, for date night, for an afternoon out with friends, travel, etc., here’s a good way to go about getting some milk stored.

When to Introduce a Pump

Unless you have a verified low milk supply issue (and need to pump to help establish or increase milk supply) or have an immediate need to stash milk (such as for a necessary medical procedure), I would suggest you start after birth by ignoring the pump and just focusing on establishing the nursing relationship with your baby. There are so many things to adjust to with your new normal of having a newborn, there’s no need to unnecessarily complicate your life right now. As feeding gets easier and faster a couple of months in, then you can think about adding the pump to the equation and starting to save milk.

If you will be returning to work, you can start pumping about 2 weeks before your first day back. Unless you have verified low supply, 2 weeks should be an adequate amount of time to start pumping and stashing. If you have concerns about your supply, please reach out to a lactation professional to assist you.

What Time of Day and How Often to Pump

It is helpful to first understand the body’s cycle of milk making. Our bodies need two hormones to nurse:

  • Prolactin, the hormone that makes the milk, and
  • Oxytocin, the hormone that causes muscles contractions to help push the milk out of the body.

Prolactin highs and lows operate on a 24 hour cycle. Prolactin levels are highest in the wee hours of the morning — it can vary from person to person, but it generally peaks between midnight and 5 a.m. Conversely, the low point is around late afternoon/early evening. (This is one reason why babies may be fussy around that time and wanting to nurse more often; it’s not an indication of overall low supply, its an indication that your supply is at it’s low point in its 24-hour cycle.)

This is why some babies love nursing at night, because there is a lot of milk, while other babies are able to fill up on lots of overnight milk and then have a good sleep — both are normal.

So, if we have lots of prolactin overnight, and then it falls throughout the course of the day until its low point, it makes more sense to try to pump when we can take advantage of higher prolactin levels and you will be more likely to pump more milk. If you feel like getting up in the middle of the night to pump, by all means, I salute you. But I think most of us would rather just nurse and go back to sleep as quickly as possible. So, the next best option for most people is to pump in the morning once or twice, when prolactin levels are still high, but you are awake.

How to Add Pumping into a Schedule Already Full of Nursing

You might be tempted to wait until an hour or so after you nurse and then pump, so that you get more milk. However, that plan can potentially interfere with the amount and flow of milk that your baby is used to and expects. What can happen as a result is that if milk runs low sooner than your baby anticipates, they can get frustrated. And you might then find yourself turning around and feeding the milk you just worked so hard to pump.

Instead, I’d recommend you pump right after nursing. You might not get as much, but as explained in “How Much Milk Do You Need in Your Stash,” small amounts of extra milk add up quickly and you might not need as much stored up as you think you do. Between 0.5 oz. – 2.0 oz. is a normal amount to get after a nursing session — because your body is used to providing a full supply of milk for your baby. More than that might be a sign of over supply, and over supply comes with its own issues.

After about 2 weeks of a consistent routine, your body may adjust and you might be able to pump a bit more, too.

Storing Milk

Because you may only be getting 0.5 oz. to 2.0 oz. per pump session, it can seem like a waste of storage containers to only freeze 0.5 oz in one container. You can combine milk to store in larger batches. Just be aware that you should only combine milk of equal temperature.


Let’s say you just pumped both sides, and you got 1 oz. on one side and 0.5 oz. from the other.

You can combine the milk from both containers into one container, because they are both at body temperature.

You can then put that milk into the fridge.

The next time you pump you get another 1 oz. and 0.5 oz. and combine those together and put that 1.5 oz into the fridge.

Once this second batch of milk is chilled to fridge temp, you can add it to the first container, totaling 3 oz. (a typical amount for one feeding) and freeze it.

How Much Milk to Feed

To make it easy, here’s the calculator for figuring out how much milk you will need based on how long you will be away from your baby.

Since caregivers may be tempted to overfeed if they aren’t familiar with the 1-1.25 oz. per hour since last feeding, it can help to divide up these amounts yourself into bottles based on your anticipation of your baby’s patterns of when they feed. Marking with dry erase marker (or pen on masking tape) which bottle is for what feeding time can take the guesswork out for your care provider and prevent overfeeding and running out of milk too quickly.


Hopefully that takes some of the mystery out of how to start a freezer stash of breastmilk, whether to go back to work, to donate, or just to be able to get out of the house occationally. If you have any follow-up questions, email me at And if you want to get a personalized jumpstart on everything related to pumping, check out our Pump Prep class.













About Becca Marshall

Becca is a postpartum doula and a CLC (Certified Lactation Counselor), offering in-home, customized support for babies and families. She also teaches Pump Prep, a class designed specifically for those who need to pump. She has been with Purple Lotus Doulas since 2013.

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