How to Warm Up Formula

Tips for Preparing Your Baby's Formula

Your baby is finally here, and with his arrival comes all sorts of new tasks such as preparing and warming up formula. Handling the job safely means your little one gets the yummy warm formula he needs without getting sick or burning his delicate little mouth. Proper storage and handling are also important to protect your little one’s immature immune system from foodborne illnesses.

Preparing Formula

Woman feeding a newborn baby from a bottle

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Before you handle the formula or any feeding items, it’s essential that you first thoroughly wash your hands with warm water and soap. Bacteria from diapers, food, pets and other common sources can get into the formula if you forget to wash.

Check the “Use by” date on the formula before you open it. Mix the formula using the instructions on the container. Tap water should be safe to use if you are connected to a public water source. If you’re unsure about your water, use bottled water to make the formula. You can also boil your tap water, and let it cool to room temperature before making the formula.

Warming Up Formula

Your baby can drink formula at any temperature. It doesn’t need to be warmed for safety purposes. But some babies prefer a slightly warmed version of their main nutrient source. Warming the formula evenly without getting it too hot is the key.

One safe way to warm formula is to hold the bottle full of prepared formula under hot running tap water for a few minutes, or fill a bowl with the hot tap water and place the bottle in it.

You also can use the stove to heat up the formula, but don’t put the bottle directly over the heat source. Start by warming water in a pan on the stove burner. Slide the pan off the heat source before popping the prepared bottle in the hot water. Let it sit until the formula is lukewarm.

Another safe option is a bottle warmer. Follow the instructions with the machine to heat the bottles of formula properly.

Avoid the microwave for heating baby formula. The microwave tends to heat food unevenly. Even if you shake or swirl the formula in the bottle, certain spots may still be much hotter than the rest. When your baby gets to those spots, the hot formula could scald her mouth.

Testing the Warmed Formula

Woman feeding a newborn baby from a bottle

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Formula is ready for your baby when it’s lukewarm. It shouldn’t be hot because it can scald her delicate mouth. Swirl the formula in the bottle after warming it to distribute the heat evenly. Test the warmed formula on your own skin. Put a few drops of the formula on the back of your hand where your skin is sensitive. If it feels hot to you, let it cool down before feeding your baby. Test it again after a few minutes. The liquid should just feel lukewarm.

Storing Unused Formula

It’s best to mix just enough formula for one feeding. Storing prepared formula increases the risk of bacterial growth that can make your little one sick. Toss any leftover formula in the bottle that your baby doesn’t drink. Bacteria from his mouth can contaminate the formula, which multiplies as it sits.

If you do mix multiple bottles of powdered formula in advance, you can safely store them in the refrigerator for up to 24 hours. Once you open a container of ready-made formula, concentrated formula or prepared formula made from concentrate, you can keep it in the refrigerator for up to 48 hours. Use the open containers first before opening or mixing new formula.

Unlike breast milk, you shouldn’t freeze formula. The freezing process can break down the components of the liquid. To ensure your little one gets the necessary nutrients without getting sick, use the formula within the safe refrigeration window or toss it.

Formula Safety Tips

Formula feeding is relatively straightforward, but you should keep a few important points in mind to keep your little one safe.

  • Sterilize bottles and nipples before the first use by boiling them for five minutes or in a bottle sterilizer.
  • Wash bottles in hot, soapy water or in the dishwasher after every use.
  • Store prepared formula at room temperature for no longer than one hour. The warm room temperature is ideal for bacterial growth, which can make your baby sick. Use the formula, or put it in the refrigerator before the hour passes.
  • Label prepared bottles or opened ready-to-use formula with the date and time, so you can track it easily. Toss the formula after it passes the 24-hour or 48-hour mark, depending on the type of formula used.