Why is Baby Bottle Foaming? [PLUS Tips for Preventing Foamy Formula]

Balint Horvath, PhD

Writer, parent, and veteran of baby feeding battles.


Preparing your baby’s bottle should be as simple as 1-2-3 and in most cases it is, until you see bubbles and foam in the mixture! You start asking why your baby bottle is foaming and if it’s something you should be concerned about. Could there be something wrong with the formula or even the water?

The quality, ingredients, method of dilution, and temperature of the water influence how much infant formula foams during preparation. Soap residue left behind in bottles that haven’t been rinsed well after washing can cause foamy formula while some brands foam more than others!

Key takeaways

  • Soap residue, the formula’s recipe, and natural state as well as air bubbles are all reasons why your baby bottle is foaming.
  • It’s not unusual to have some well-known baby formula brands foaming during bottle preparation!
  • While foamy infant formula is unharmful it can result in unpleasant symptoms such as gassiness, reflux, or colic.
  • My simple guide to preventing baby bottle foaming is easy to follow and use when preparing for your bottle-fed infant. 

Why is the formula in a baby bottle foaming? 

Let’s talk about some of the reasons why the formula in your baby’s bottle is foaming.

Soap left inside the bottle 

A simple culprit for foaming baby bottles is soap residue! If you’ve been handwashing the bottles, some detergent may stay behind if you don’t give them a thorough rinse. If your baby bottle smells of soap, get rid of it by rinsing well before using it for feeding again.  

The following could be the reason why soap is left inside the bottle when cleaned in the dishwasher:

  • Using the wrong detergent
  • The water in your area is “hard” making it more difficult to rinse off the soap
  • The rinse cycle wasn’t used
  • The bottles are drained properly after the wash cycle

Soap left inside the baby bottles not only increases bubbles and foam in the formula but it’ll impact the taste of the milk. It’ll also make bottles cloudy. Using Dawn dish soap to wash baby bottles won’t leave behind residue when rinsing the feeding items well. 

The natural state of the formula 

Infant formula comes in powder form, as a concentrate, or in a ready-to-drink formulation. Most parents are familiar with powder formula which is mixed together with water before feeding their baby. In order to dilute the formula and water, the bottle has to be shaken vigorously and this action alone will cause some foaming to take place. 

Foaminess in formulas is generally not something to get overly concerned about but reducing it will give your baby a more comfortable feeding experience. While foaming is the natural state of most infant formulas, premium-quality brands are less likely to make bubbles when the contents are shaken in the bottle. 

Air bubbles when you shake the milk 

Most liquids that are shaken will have some air bubbles in them and this is no different when preparing infant formula in bottles. However, vigorous shaking of the bottle to ensure the formula and water is well-combined can result in air being trapped in the mixture. 

Experienced bottle-feeding parents know what happens when babies ingest air with their formula! Your baby becomes colicky, battles reflux, or struggles with gassiness, all conditions that make your little one uncomfortable and fussy. 

Well-known formula brands notorious for foaming

Enfamil formula foamy

If your baby’s Enfamil formula is foamy, you could be preparing it the wrong way around. The manufacturer’s guidelines recommend adding water to the bottle first before scooping in the formula. Make sure you use the right quantities of each before giving the bottle a good shake to dilute the contents. 

Aptamil formula foamy

If you’re battling with frothy Aptamil formula, consider using boiled water that has been cooled down for 30 minutes before mixing with the powder. This can reduce the number of air bubbles trapped during the dilution process. 

Following the preparation instructions should help to eliminate foam when using Aptamil but if you’re still getting it, let the bottle sit a few minutes before feeding your little one.  

Watch this video demonstrating how to prepare a bottle using the Aptamil formula.

Similac (Gentlease) formula foamy

Ingredients such as corn syrup and palm oil can make infant formula foamy. Both of these ingredients are found in Similac (Gentlease) formula so it’s not unusual to see it foaming up when shaking the bottle. 

If you’re worried it’ll give your baby more gas, let the bottle sit for a few minutes before feeding. This helps to reduce the bubbles and in turn, calm down the foaminess. 

Kendamil formula foamy

If you’re wondering why your Kendamil formula is frothier than other milk brands, don’t stress! The manufacturer uses whole milk in the recipe which causes the formula to froth up as soon as you shake the bottle. 

Instead of shaking the bottle vigorously to dilute the contents, the manufacturer recommends mixing the formula by stirring it to reduce the frothiness. Swirling the bottle is another way of decreasing the foaminess. 

Bobbie formula foamy

It’s a rare occasion when organic Bobbie formula foams when diluted with water! If you’re struggling with foaminess when preparing for bottle feeding, make sure you follow the instructions on the packaging which are as follows:

  • Wash hands, bottles, and accessories before making up the mixture.
  • Add warm water to the bottle (recommended temperature is 100°F)
  • Scoop the right quantity of formula into the bottle and water.
  • Seal the bottle and shake well.

Following this preparation guideline should reduce any signs of bubbles or foam in the bottle.

Earth’s Best formula foamy

Earth’s Best is another organic formula that can foam if shaken too much during preparation. However, letting it sit or putting the prepared mix into the refrigerator for a few hours settles the foam down. Many parents using this formula prepare in batches and leave them in the fridge before feeding their babies. 

Is foamy baby formula unhealthy?

While foaming baby formula doesn’t look great, it’s not unhealthy or dangerous for your bottle-fed infant. No matter how carefully you prepare your baby’s formula, there’s going to be some foam but it’s not harmful.

However, eliminating the bubbles beforehand helps to reduce gassiness, colic, or spit-up when feeding foamy formula to your baby with a sensitive tum. 

Does foamy baby formula cause gas? 

Foamy baby formula can cause gas if your baby has a delicate digestive system. While it can make your baby uncomfortable, don’t panic! Burping your baby, laying them on their back and moving their legs in gentle bicycle motions, or giving them some tummy time will help reduce the gas buildup

How to prevent the baby formula from foaming

There are some simple ways to prevent your baby formula from foaming and I’ve listed them below for you:

  • Preparation: Water should be added to the bottle first before scooping in the powder. Following the manufacturer’s instructions when preparing your baby’s bottle is highly recommended!
  • Dilution method: Most baby formula manufacturers recommend shaking the bottle well to dilute the contents. However, stirring or swirling the mixture can reduce foaminess while sufficiently combining the formula and water. 
  • Remove the foam: Before giving your baby their bottle, scoop out the foam at the top of the milk with a spoon. 
  • Prepare in advance: Preparing your baby’s bottles in advance allows the mixture to settle, reducing the number of air bubbles in the formula. 
  • Use hot water: Hot water makes the frothiness dissipate faster than cold or lukewarm liquid. However, make sure the formula has cooled down before feeding your baby. 
  • Quality: Top-quality infant formula brands or those specially formulated to reduce gas and reflux in babies tend to foam less when mixed with water. Consider Dr. Brown or MAM anti-colic bottles to reduce foam production as well. 
  • Concentrated or ready-to-drink formulas: These formulations don’t froth as much as their powdered counterpart but check the list of ingredients for additives before deciding to use them. 

Using a fork instead of a spoon when stirring the formula in the water helps to reduce foaminess. A vented bottle design helps to prevent infant formula from foaming and when all else fails, consider using a mixing pitcher designed to prevent clumping and frothing of the milk. 

Final Thoughts

While it’s not unusual for the formula to foam in your baby’s bottle, reducing it is recommended if you want to give your infant a happy feeding experience. Using my tips for prevention in this article plus a great dishwasher for baby bottles will eliminate any reasons for foaming formula! This way, you can relax knowing your baby is drinking foam-free formula!

Photo of author


I’m Balint, founder of this site and a father (and dad) to a baby-turned toddler. I found the world of babies so fascinating that I started a blog dedicated only to that topic. By the way, I studied physics, engineering (PhD, MSc), and therefore I do a thorough research when I write about something. Since it’s a blog, of course I also write about my personal experiences.

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