I am not sure when I should start using my freezer stash... I am an over producer and am pumping more milk than my baby is consuming, so while I am at work I leave bottles of fresh milk for him and freeze the rest. My freezer stash is getting out of control and I have had to buy a separate mini freezer to store it.

I understand that some women start to use their frozen milk when they go out or run out of fresh milk, but if I am producing enough fresh milk when to give him while I am at work and still have extra — when do I start using the frozen milk?

  • Are you rotating your stash? Using the oldest as you replenish it? It doesn't last forever.
    – JPhi1618
    Commented Oct 26, 2015 at 18:28
  • I was for a little bit, then I thought why am I giving my baby old milk when I can give him fresh milk since it is not an issue of not having enough. But I know that the older milk isn't going to keep forever so I am not sure when to start using it...
    – Kmascavage
    Commented Oct 26, 2015 at 20:57

3 Answers 3


When to start using frozen milk depends on when the milk was pumped. This is because of two things:

  1. The nutritional content of milk changes over time. This is most significant when comparing milk from the first couple weeks to milk after a few months (see this more thorough answer), so if you're using milk from when the baby was only days old, you should mix it with "now" milk to get a better nutritional balance.

    NOTE: It's not bad for the baby to drink milk from a different lactation period, it just isn't quite as well-balanced nutritionally. Also, once you're well into the "mature" lactation phase there's not as significant a difference over time (e.g., milk from Month 3 and Month 4 are approximately the same).

  2. More importantly: Milk can spoil, even when frozen. (Depending on the freezer type, 3 to 6 months.) Use the oldest milk first, and discard if it's older.

Aside from that, there's not really a hard and fast rule beyond "what works best for you." When I went back to work with my youngest, I brought along bottles of breastmilk for him that were about 2/3 frozen, 1/3 fresh. That was roughly based on my supply, both what I could pump daily and what I had in my freezer. It would sometimes change over time. For example, Mondays might be as much as 1/3 fresh, 2/3 frozen if I'd had a very productive weekend. There were some days that were all frozen milk because of a storage mishap with the fresh-pumped milk. A half-and-half ratio would allow you to "cycle" your milk (freeze half of what you pump each day, and you'll basically always be feeding half fresh and half two-months-old milk).


Ultimately, you're going to need to either donate or toss some of it.

First, hopefully you're rotating your stock (i.e., sometimes freezing all of it and giving him during the day frozen older milk). Milk in the freezer lasts for a fairly long time, but not indefinitely; Medela for example recommends 6-12 months, and that assumes you followed good practices.

You should also verify from time to time that frozen milk is still acceptable to your child. Various reasons - particularly, lipase levels, poor storage practices, freezer defrost cycles, for example - can cause it to go 'off' faster; and sometimes your child is just more sensitive. Make sure he's still happy to eat your milk frozen - otherwise there's not much value to keeping it in the freezer, is there?

Second, the most likely reason you might need a significant storage quantity is if you get sick. If you catch a sinus infection, for example, both the infection itself and the medicines you may need to take to treat it may reduce your supply - or you may wish to take medicines you'd prefer him not ingest, and then not feed him at all (just pumping and tossing) for the week or so it takes to treat the infection. (Talk to your doctor before taking any medicine that's not approved for breastfeeding mothers, even if you choose to toss the milk - some medicines may have metabolites that last longer than you think.) In any event, that's when you're most likely to need the excess; so I would keep enough for a full week's feeding at least. How much more than that is up to your preference and your storage abilities.

Third, you may wish to think about whether you're likely to take a trip without him - either for work or vacation - which would necessitate using stored milk for an extended period of time while his caretaker (dad, grandma/grandpa, etc.) feeds him from the frozen supply. If you travel regularly, you may need a higher stash than normal to avoid needing to ship milk back (which can get expensive).

But either way, make sure you've got usable milk - it would be very frustrating to finally need it, and find that your son doesn't like it or that you have a higher lipase level than normal and the milk goes off quickly.


I was an over producer at first and when I returned to work I cut out a pump at a time. (Exclusively pumping for other issues). I had over a 1000 ounces in the freezer and am now pumping 3 times a day and getting about 20 ounces (was at 60 ounces per day at my peak) at 7 months postpartum. I am mixing the fresh with the frozen now, about 2 bags per day. I'm not sure what your goal or situation is but getting a lot stored isn't helpful if you aren't planning to use or donate it. Don't waste your time you could be spending with your baby. However, if you are exclusively pumping it's nice to be able to cut down and get your life back a little bit of you have a huge store. :)

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