How to Properly Collect, Store & Prepare Breastmilk

How to Properly Collect, Store & Prepare Breastmilk | Baby Chick

How to Properly Collect, Store & Prepare Breastmilk

Almost every breastfeeding mother has a time when they need to pump, store, and prepare their breastmilk for their baby. If you have to go back to work and want to continue breastfeeding, if you want your partner to help or have to run errands, or any time you have to be away from your little one for several hours at a time, pumping your breastmilk can be very convenient and at times necessary. As a postpartum doula, a lot of my clients that I have helped have often needed advice and assistance on how to properly pump and store, and sometimes preparing the breastmilk isn’t done properly. I wanted to share some tips below to answer any questions that you may have about properly storing and preparing your breastmilk. Hopefully these tips will make this process a lot easier!

Collecting Breastmilk

  • The first thing that you should do is wash your hands with soap and water.
  • Then, make sure that you have washed the bottles and breast pump parts in hot, soapy water. Some people boil water and place the pump parts and bottles to sterilize and others use their dishwasher since the temperature it reaches also helps sterilize as well. Just make sure that the rest of the dishes are pre-rinsed. You don’t want leftovers on them.
    • NOTE: Do NOT wash the tubing in a dishwasher or sterilize in any machine. This can cause water to get into the tubing which can cause water to get into the machine and have it break.
  • You want the parts to air dry so you can lay them out on a clean towel or paper towel. You can also use a drying rack.
  • If you are unsure how to use your pump, read the instructions in the book that comes with your pump and follow the suggestions.  You can also watch some YouTube videos to make sure that you’re assembling and using the pump and parts properly.
  • I like to let people know that you do not have to sterilize your pump parts every time after you use them. It’s recommended that you sterilize the parts once a day but between using them, you can hand wash with soapy hot water.
  • When you are ready to start pumping, be sure that you have the right size breastshields so that your nipple fits comfortably.  The standard kit that most families purchase usually only comes with one size shields but there are different shields available that you can buy separately. Most of my clients experience that the shield it comes with is too small so check if you need to purchase a larger size. Medela makes different size breastshields to fit all nipple sizes, from small to extra large.
  • Lactation consultants recommend that you don’t start introducing a bottle until breastfeeding has been established and is going well. I’ve heard from different lactation consultants many different times to introduce a bottle. Some have said three to four weeks and others have said longer than six weeks. I usually recommend to start of slow and introduce one bottle at two to three weeks and slowly build up from there. I’ve seen many babies only want the boob because their parents never introduced the bottle until later and I have had other babies only want the bottle because they introduced the bottle too soon and for too many feedings.
  • If you are returning to work, you will want to begin pumping to store milk one to two weeks before you return. A lot of working moms use the fresh milk they pump at work for feedings the next day. They bring home that fresh milk and refrigerate it for the next day’s feedings. So Friday’s milk is used for Monday. You want to save your frozen milk for emergencies.


Storing Breastmilk

  • I want you to know that it is normal for pumped milk to vary in color, consistency and scent depending on your diet. When you pump your milk, you will notice when it’s sitting for a little while that your milk will separate into layers. The cream will rise to the top and be a lighter color.
  • A lot of people wonder if they can combine breastmilk together. You can continue to add small amounts of cooled breastmilk to the same refrigerated container throughout the day, but you don’t want to add warm milk to already cooled milk.
  • For storing, pour your milk in breastmilk collection bottles or in disposable bags specifically designed for breastmilk. The bottle must be a clean, capped glass or hard plastic, BPA-free container. Warning: Breastmilk storage bags might tear, leak and become contaminated more easily than hard-sided containers. For extra protection, place the bags in a hard plastic food storage container with a tightly sealed lid. Even though the disposable bags are made for breastmilk, these things still happen. I have definitely seen several mothers cry over their spilt milk so make sure that you store it carefully.
  • To easily find the oldest bag of stored breastmilk, check out Milkies’ The Freeze.


  • Again, seal containers tightly to prevent any leaking and write the date and time on a piece of tape on the bag or bottle. This way you will know which is the oldest since you want to use the oldest milk first.
  • You also want to place the containers in the back of the refrigerator or freezer, where the temperature is the coolest. If you don’t have access to a fridge or freezer, store the milk temporarily in an insulated cooler.
  • I recommend that you freeze your breastmilk in two to five ounce portions. Small amounts thaw faster so you will waste less milk this way, save more time, and will avoid over-feeding your baby. A lot of parents want their babies to finish the whole bottle since they don’t want to waste a drop, but you do not want to overfeed your baby. Also, be sure to leave some extra room at the top of the container or bag since the liquid will expand when frozen. You don’t want the bottle or bag to burst.
  • Read my Breastmilk Storage chart to learn how to store breastmilk.

If your baby was born premature, these guidelines may differ slightly.  You should check with your health care provider for the recommended storage guidelines for your specific situation.

Preparing Breastmilk

  • When you are ready to prepare the breast milk, you want to gently swirl the warmed bottle to mix the milk layers. Do NOT shake the milk. That damages the milk.
  • If your breastmilk has been in stored in your fridge, to warm the bag or bottle you can either use a bottle warmer or place it under running hot water, in a cup or bowl full of hot water. Do NOT microwave your breastmilk or heat quickly on the stove. This also damages the composition of the milk and can create hot spots which can scald your baby’s mouth. No fun.
  • If you’re trying to thaw your frozen breastmilk, first move your milk to your fridge the night before. If you need it sooner than that, you can hold the bag or bottle under warm running water. It will obviously take a longer to thaw and warm than a cool/cold bag of breastmilk that was stored in the fridge. When you have a hungry baby, that might not be ideal.
  • Another major question that I get asked is if you can refreeze your breastmilk. No, you can’t. Do NOT refreeze. Once it’s frozen and then thawed, you must use it within 24-hours (which that is how long it is safe in the refrigerator.)

So there it is! My advice on how to properly collect, store, and prepare your breastmilk. I hope it helps! 🙂

About the Author /

Nina is The Baby Chick® & CEO of Baby Chick®. She is a baby planner, birth doula, postpartum doula, childbirth educator, newborn care specialist, and a mother. With over eight years of experience, she has supported hundreds of families during their pregnancies, births, and postpartum journeys.

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