How to safely prepare formula for your baby


Being pro breastfeeding does not mean being anti formula. As an IBCLC lactation consultant, my job actually includes education on feeding infant formula. This includes helping families choose an infant formula that is right for them based on solid evidence based research, bottle selection and techniques for bottle feeding. It also includes how to safely prepare formula. If there was more education and less demonizing of formula, families would feel less guilt and stigma around just trying to feed their babies while feeling more confident in the process. Let’s talk about safely preparing formula.

Formula-to-water ratio:  Follow the directions on your particular can of formula. For most powdered formula, the recommendation is 1 level scoop of formula (not packed down) per 2 fl oz of water. Be careful not to add too much water as this dilutes essential nutrients and can affect baby’s nutrition. Too little water may cause baby’s kidneys and digestive system to work too hard and may cause baby to become dehydrated. You also do not want to use breast milk to make formula unless under the direct supervision of a pediatrician or pediatric dietician as this hyper concentrates certain nutrients and can lead to medical complications.

Reminder: Powdered infant formula is NOT sterile and should not be fed to premature babies or babies with compromised immunity unless directed and supervised by your doctor. Typically most pediatricians will recommend ready-to-feed formula (already a liquid) for babies under 2 months. When preparing baby’s powdered infant formula, it is important to know that recommendations can differ based on several factors including  baby’s age and the safety of the water. Your pediatrician should be guiding you on formula preparation based on your unique baby’s health. For infants under 2-4 months of age, those who were born prematurely and those who have a weakened immune system, hot water should be used to prepare formula to kill any microbes. To do this, boil the water and let it cool for about 5 minutes, and then wait for the mixed formula to cool down before giving it to baby. After 2-4 months, it’s safe to prepare powdered infant formula by mixing it with tap water (filtered or unfiltered) and following the manufacturer’s instructions on the container.

Preparing formula with boiled water:

Ask your baby’s doctor if you need to use cooled, boiled water for mixing and if you need to boil (sterilize) bottles, nipples, and rings before use. If you choose to boil, follow these steps:

1. Bring water to a rolling boil for 1 minute, then turn off the heat.

2. Let the water cool for about 5 minutes before adding the powdered formula. Making formula with boiling water can cause clumping and decrease the nutritional value. The hot water, though, is what kills harmful bacteria in the formula.

3. Once the formula is mixed, run it under cold water or leave it on the counter for a few minutes to cool down to the right temperature for baby. Before feeding, put a few drops on the inside of your wrist to make sure it is not too hot. Do not offer the bottle immediately after mixing.

4. Feed or refrigerate the prepared formula.

Note: If you are concerned about lead or other harmful substances in your water, talk to your healthcare professional before making formula with tap water. Bottled or filtered water can contain bacteria and should still be boiled.

Mixing Tips for Powdered Formula

Single bottle instructions

1. Wash your hands thoroughly with soap and warm water.

2. Measure and pour desired amount of water into the baby bottle. Make sure to measure the water FIRST.

3. Add unpacked, level scoop(s) of powder formula to the bottle as directed. Return dry scoop to can. (1 scoop of formula per 2 fl oz of water is a typical recipe.)

4. Put the cap on the bottle and gently swirl or shake. Stirring often causes less bubbles to be formed which if swallowed can make baby gassy.

Tip: Moving your wrist in a twisting motion helps powder formula mix more quickly and more thoroughly.

5. Feed or store immediately in refrigerator. You can mix 24 hours worth of formula in a pitcher and keep it in the fridge to pour out and feed to baby. Pour the correct amount from the pitcher into a clean bottle and either feed cold or reheat.

The can of powdered formula can be used for one month after it has been opened. Manufacturers don't recommend using the formula after the 30 days of opening because the nutrients start to degrade. Store powdered formula with the lid tightly shut in a cool, dry place – but NOT in the refrigerator.