Woman pumps milk with manual breast pump

Breastfeeding & Feeding

Breast Milk Storage Guidelines

Pumping, Storing, and Heating Breast Milk Correctly

Breast milk is precious and strengthens your baby's immune system. It is worth having some on hand for greater flexibility and to be prepared for emergencies such as illnesses requiring medication. There are a few things to consider: how to express breast milk correctly, how long it can be stored for, and what should never be done when heating it. Read on to find out all this and more!

1. What is the best way to express breast milk?

Milk can generally be expressed by hand, but many breastfeeding women prefer to use a breast pump with which the breast can be emptied quickly and easily. The same applies here as with breastfeeding: practice makes perfect! It is not unusual for there to be just a small quantity of milk at the beginning, or for the quantity to vary greatly from time to time.

There are both economical manual breast pumps, which are used to express milk by hand, as well as double electric breast pumps, that can empty both breasts at the same time. Electric breast pumps are even available to hire in some regions or the costs are sometimes covered by the health insurer. Under certain circumstances, for example with a premature baby, breast pumps may be available free of charge on prescription – it is best to ask your doctor or insurance company.

Either way, if you are planning to express milk, make sure you get the right breast pump before the birth, so that you have it to hand when you need it. If you have access to midwives or lactation consultants, they can inform you about all the options at an early stage. Talking to experienced mothers can also help you to find the right pump.

What do you need besides the pump?

In addition to the pump, you also need something to store the milk in. It must be food-safe, sterile, and possibly suitable for freezing. Special containers suitable for sterilizing are ideal for this purpose. It is important that plastics are BPA-free. Also helpful: an ointment for your nipples and nursing pads in case your breasts are prone to leaking.

When should I express milk?

There is no such thing as THE perfect time to express breast milk. Simply give it a try when the time suits you. For many breastfeeding mothers, expressing is easiest in the morning after baby has fed for the first time, because more milk usually builds up overnight. Some women express after breastfeeding or, if it is easier (because the let-down reflex has already been triggered), from the other breast during breastfeeding. Don't worry about leaving too little for your baby: the breast "boosts production" when the demand is greater.

The best way to express is to create a pleasant environment so that you can relax and express in peace. Always make sure that you are well hydrated and that there is a glass of water close by. If you have difficulty triggering the let-down reflex, stay close to your baby – it sometimes even helps to look at a photo of your baby. Whatever happens, don't worry if it doesn't go perfectly in the beginning or if you only express small quantities. Expressing effectively requires lots of practice!

MAM Storage Solution cup in the refrigerator, close up

2. How long does breast milk last how should I store it?

Breast milk should only be stored in a sterile beaker or in breast milk bags. You can also express breast milk directly into a sterilized bottle, store it in the refrigerator, then heat it to the right temperature for feeding, using a water bath or bottle warmer.

Overview: storing breast milk

  • At room temperature for 4 hours
  • In the refrigerator (32-39°F) for up to 3 days
  • In a freezer compartment with separate door (-4°F) for 3 months


  • Do not refreeze milk after defrosting!
  • Hygiene is extremely important for babies, so make sure that all containers are completely clean.

Freezing and defrosting breast milk correctly

As described above, breast milk can also be frozen and kept in the freezer for up to 3 months. However, check the actual temperature of your freezer: freezer compartments integrated in refrigerators are sometimes not as cold as they should be (-4°F is ideal). Breast milk expands like any other liquid when it is frozen, so do not fill the container to the brim.

3. How should I heat breast milk?

In order to retain as many vitamins and essential fatty acids as possible, the milk should only be heated gently. You can do this in a water bath or in a separate bottle warmer that does not heat to higher than 98.6°F.

Important when warming and defrosting breast milk:

  • Breast milk should not be heated in the microwave or directly in a pan on the stove.
  • Germs grow particularly quickly in warm milk: it should therefore be consumed immediately.
  • Defrost frozen breast milk correctly: overnight in the refrigerator or under increasingly warm running water – do not allow the milk to defrost at room temperature!
  • Leftover milk in the bottle must be poured away.

Things to be aware of with frozen breast milk:

  • Frozen breast milk looks different depending on its composition – a yellowish, brownish, or bluish color is therefore not unusual. Freezing can change the smell and flavor of the milk.
  • It is best to freeze breast milk in small portions of approx. 2–4 ounces and label containers with the date.
  • It is a good idea to freeze a small quantity initially in order to find out whether your baby will accept defrosted milk.
  • Defrosted milk can be kept in the refrigerator for another 24 hours. However, it must not be frozen again!

And one final tip: the production of so-called "mature" breast milk only starts around two weeks after the baby's birth. In the first two weeks you should therefore not start stocking up on larger supplies for later, because the composition of breast milk changes considerably during this period.

Good luck expressing!