1. Get the Right Supplies
You need the pump, shields, and all other regular ol’ pump accessories. However, you won’t actually need your bottles! Use milk bags specific for the freezer. Check these out (super common and compatible) or these ones from Lansinoh. Both boxes come with the adaptor part needed.
Some friends absolutely loved these bags because they eliminated the extra step needed with the previous bags mentioned. These bags freeze, then can be directly connected to these parts and the whole thing becomes a bottle! You don’t have to thaw and then pour the breast milk from a freezer bag into a new bottle.
2. Mark It
You’ll need a good sharpie to mark the ounces and date on each packet. I find black the easiest color to read on the bags.
3. Freeze Time
After you pump fresh milk into the bags, label the bag with the date and ounces, seal the bag and let it cool for a bit. Place in the back and/or bottom of the freezer at your freezers coldest areas. Ensure you don’t use the door to storage frozen milk as items on the door or the entry point of the freezer are subjected to the most amount of temperature change.
If you can keep your bags upright to freeze, great! Otherwise seal super, super well! After that, it doesn’t really matter if they are laying down or upside down! Just make sure you keep some sort of order/organization to them so that you can always use the older bags first! I never found the need to use an organizer in my fridge, especially if you have a lot of milk to freeze (then the organizers just overflow and become useless anyway). Some friends found these simple containers useful – these are also similar. This kind appears to be the most space saving.
4. Thaw & Serve
When thawing breast milk bags, try using a cup of water hot or run under the faucet from cool to hot! I find this the easiest route if you can plan ahead for that frozen milk feed. Avoid letting it thaw at room temperature over a longer period of time.
Note: Previously frozen milk may be kept in the refrigerator for up to 24 hours after it has finished thawing. You cannot refreeze the bag of frozen milk.
5. Consider This
Remember that frozen milk will expand so be careful not to fill your bags too much. This might mean switching bags part way through a pump session OR pumping into a large bottle first and then pouring into appropriate freezer bags.
6. Bottle Pumped Milk Can be Transferred
If you pumped into a bottle but changed your mind at the end of the session and want to freeze the milk instead, no problem. Just carefully pour the milk into a pump bag and label appropriately.
You might also be interested in my post about pumping at work!