Is It Safe to Refrigerate Formula?

Medically Reviewed by Dan Brennan, MD on April 18, 2023
3 min read

Having a new baby comes with a whole new routine. This includes the frequent feeding of your baby. If you choose not to breastfeed and opt for formula instead, there are some things you need to know about formula preparation and storage.

Water for Formula Bottles. Never use tap water to mix formula bottles unless you’ve sterilized it first. Tap water contains additives that may be harmful to infants. Using only bottled water to mix formula is the safest choice for your child.

Remove the water from your heat source. Allow it to cool completely before mixing in the formula. Water that is too hot can harm your baby. Once you boil water, use or refrigerate it within 1 hour. If it stays out longer than an hour, pour it out and start with fresh water for your next bottles. Alternatively, you can purchase purified water in jugs at your local grocery store.

Preparing Bottles. Each brand of formula has instructions for how much formula to mix in per ounce. Follow this guideline strictly. Mixing in too much water can fill your baby up without providing adequate nutrients. Mixing in too much formula may lead to dehydration or constipation.

Be sure to use a clean bottle for each feeding. To keep your baby healthy, wash bottles between uses with hot, soapy water and sterilize them as needed.

Storing Bottles. You can prepare formula bottles one at a time according to how often your baby is hungry. Formula will stay good in the fridge for up to 24 hours, so many parents prefer to mix enough formula for an entire day. Consider how many ounces your baby drinks per feeding session, and then mix a pitcher of formula or individual bottles for each feeding.

To avoid waste, don’t mix more formula than your baby will drink in a 24-hour period. Once a bottle is prepared or taken from the fridge for feeding, use the formula within 1 hour or throw it out. You cannot re-refrigerate formula once it has been warmed or reaches room temperature.

The reason experts recommend you throw away unused formula is because bacteria can begin to grow. Babies are much more sensitive to the dangers posed by bacteria than adults are. Their immune systems haven’t yet had a chance to build up the antibodies used to fight off illness and infection.

Bonding with Baby. There is a misconception that you will not bond with your baby as well if you feed them with formula instead of breastfeeding. This is not true. Cuddle close to your baby when you bottle-feed, and share the love! Make eye contact and use a soft voice to talk to your baby while you feed them.

Breastfeeding gives you a chance to bond with your baby, but formula-feeding gives everyone in your family a chance to bond! Encourage dad, siblings, and grandparents to hold and feed your baby. This will help your baby to feel connected and more comfortable with each member of your family. It will also ease the transition of your baby being away from you if and when you return to work.

Offering Bottles. Start out feeding your infant with bottles that are cold or at room temperature instead of heated. Your baby will never know the difference if you begin this way. However, they may refuse cold or room temperature bottles if you begin by giving warm ones.

If your baby prefers warm bottles, invest in a bottle warmer rather than using boiling water or a microwave. Bottle warmers are safer because they are specifically designed for baby bottles and provide a more consistent temperature.

Test the temperature of your child’s formula on the back of your hand before offering the bottle to your baby. If it feels too warm on your wrist, it could burn your baby’s mouth.

Diapers. The poop of a breastfed infant is very different from that of a formula-fed infant. Your baby on formula may have dark, smelly feces. This should not be cause for concern and is very normal. Generally speaking, your baby’s diapers will be smellier and firmer than if your baby was breastfed.