A bunch of baby bottles in a basin, being washed

How To Get The Smell Out Of Baby Bottles: Nasty Odors, Begone!

Every parent is a warrior in the battle against nasty smells. The enemy is found in diapers, spit up, and of course the dreaded used bottles during that bottle feeding phase.

Bacteria which feast on the leftovers from your baby’s meal are to blame for the horrible odors.

There are many factors determining how difficult it will be to remove smells from baby bottles and bottle nipples. When the bottles are half full and curdled or simply seasoned veterans who laugh in the face of ordinary cleaning techniques, it may be time to bring in the heavy artillery.

A bunch of baby bottles in a basin, being washed

This article will go over everything from bottle basic training to the most elite cleaning tips.

By the time we’re through, no nasty bottles that smell like sour milk will stand a chance against you. You’ll know everything you need to do to get rid of sour milk smells.

Breast Milk Smells Vs. Baby Formula Smells

So, breast milk or formula? What’s the difference?

The first thing to figure out is the source of the foul odor. While most breast milk has little or no smell, some may develop an unpleasant odor or sour milk smell.

This does not always mean the milk has gone bad, though! Unlike formula, breast milk undergoes subtle changes depending on the mother’s diet as well as any medications she may be taking at the time.

If you check and the bad smell is not present in freshly expressed milk, only then will you know if the milk has indeed gone bad.

Many parents are also not aware of the difference between breast milk and formula when it comes to how long it takes for it to go bad.

While formula must be used within a couple hours of being at room temperature before it begins to curdle, breast milk is able to last four to six hours under the same conditions.

Breast milk is able to stay fresh so much longer because it is a live food, full of antibodies and other ingredients which fight off bacteria.

Glass Vs. Plastic Bottles

The material from which a bottle is made can affect how quickly bad smells build up.

This may come as a surprise to younger parents, but baby bottles and nipples were once exclusively made from glass.

Nowadays glass baby bottles are experiencing a bit of a revival due to fears of BPA, a harmful chemical that used to be found in plastic bottles. However, glass is still only a niche market.

While both glass and plastic have their advantages, glass is the clear winner if you want to prevent bad smells from taking hold again in the future.

Plastic surfaces have microscopic textures which offers bacteria endless places to set up shop and begin to multiply. A glass bottle almost always has a much smoother surface, and so bacteria have a harder time grabbing a foothold.

The less spots there are for bacteria to begin growing, the longer it takes for the resulting smell to develop.

How To Get The Smell Out Of Baby Bottles

If you’re trying to get those nasty smells out of your baby’s bottles, here’s a list of solutions you need to know about:

Soap And Water

Once a sour smell has set in, the harder it will be for you to remove it – so the best defense is a good offense. The sooner you get to it, the easier removing milk odor will be.

Since the bacteria which cause the smell need food to really start multiplying, concentrate first on eliminating the food source.

Every time your baby is finished with a bottle, go rinse it out with warm water (not cold water) and leave the bottle lid off. Yes, I know that there’s always something else happening to distract you, or it’s 3 A.M and you’re stumbling around in the dark. Still do it, every time.

Make it a habit to rinse out your baby’s bottles and you’ve already done 90% of the cleaning process.

When you eventually come back to more fully clean all the bottles from the day, all you’ll need is some mild dish soap and hot water, as well as a bottle brush. Use water as warm or hot as your hands are able to withstand and get scrubbing.

Depending on the bottle, you may have many little pieces to clean. Just make sure you get in every little nook and cranny, then rinse out the bottle very well. If you use a soap that leaves little to no residue, then rinsing shouldn’t take too long.

Let all the pieces dry completely before reassembling or else you’ll be trapping moisture and increasing bacteria growth.

Time For Some Chemical Warfare

Try as we might to keep up with our regular inside of the bottle cleaning, eventually all of them begin to stink.

If regular rinsing with soap and water simply isn’t getting the job done anymore, it may be time to use some different techniques.

Fortunately, there are a number of options for you to choose from.

Rubbing Alcohol

Isopropyl alcohol is great for cleaning all sorts of household messes, and bottles are no exception.

  1. Take your smelly bottles one by one, and fill the bottle all up halfway with rubbing alcohol.
  2. Go back and top off each one with water.
  3. For small pieces and nipples, put them in a bowl or deep pan. Pour the rubbing alcohol and water mixture over the pieces until they are all submerged.
  4. Let everything soak like that overnight.
  5. Empty the bottles and let them air dry.
  6. Rinse thoroughly with soap and water to get all the rubbing alcohol out of any tiny holes and crevices in the pieces.

White Vinegar

The process with white vinegar is identical to rubbing alcohol.

Make a 50/50 mix and let it sit overnight, then pour out and air dry. Always make sure you’ve rinsed the bottle as well as any pieces with a lingering vinegar smell.

The solutions do a great job at pulling out any bacteria from their microscopic hiding spots along the surfaces of bottle parts.


Many people are understandably nervous to use anything as harsh as bleach on bottles their kids use for drinking. After all, the whole bottle industry was changed because of similar concerns over what chemicals can leach their way into drinks.

But don’t be scared away from using bleach, as even the CDC agrees it is perfectly safe when used correctly.

  1. First clean any soap or other chemical residues off the bottle parts. This prevents anything from chemically reacting with the bleach.
  2. Follow the instructions on the bleach container for mixing a cleaning solution. Usually it will be about 2 teaspoons of bleach for every gallon of water being used.
  3. Soak the bottle pieces for a few minutes, then drain them and let them air dry. The diluted bleach will evaporate, leaving a spotless and smell free bottle. Rinse off any pieces that don’t air dry fully.

Drinking Alcohol

No, we don’t mean for you.

When you’re in pinch and out of other cleaning supplies, try making a raid on the liquor cabinet instead. While anything with a high ethanol content will work for cleaning, vodka is probably the best option.

You don’t want a liquor with lots of added flavors like bourbon or rum, as these might leave another unwanted smell lingering after you’re done. Vodka is nearly odorless and will work well.

  1. In the same way you used rubbing alcohol, make a 50/50 mix with vodka and water.
  2. Let the bottles soak overnight.
  3. Pour out and rinse with soap and water.

Sterilizing Tablets

Another convenient option for parents who want to stay ahead of the bad odors is to use sterilizing tablets.

These tablets have been around for 100 years, and are a safe way to sterilize the bottle when you’re not at home.

All you need is cold clean water and a container with a lid.

Instructions vary between products, but the general steps are as follows:

  1. You drop one or two tablets into about a gallon of clean water.
  2. Close the lid on the container with the solution and wait 15 minutes.
  3. Fill with hot soapy water, and wash baby bottles with hot water and dish soap while you wait.
  4. The solution is ready to clean your bottles. Soak the parts in the solution for 15 minutes.

That’s it. They’re ready to use with no rinsing needed. You can also buy premade sterilizing solutions, in which case skip right to step four.

If you have particularly stubborn smells, let the bottles soak all day.

Turn Up The Heat

When chemicals aren’t able to fully eradicate the funk, maybe you need to heat things up.

Most bacteria can only thrive in a certain range of temperatures. This Temperature Danger Zone is listed by the USDA as being between 40°-140°F. Any bacteria kept within this range will be multiplying rapidly, and often producing bad smells along with them.

In order to sanitize bottles and remove the smell, you must find ways to heat everything to over 160°F.

There are a number of different ways to do this. Use whichever one is easiest for you.


One of the oldest and most reliable methods for sterilizing bottles is to use boiling water.

By definition, water boils at 212°F at sea level. (Fun fact: due to the elevation change, water boils at 202°F in Denver, and a measly 162°F on top of Mt. Everest!)

Regardless of location, all boiling water is hotter than the Temperature Danger Zone.

  1. Boil water in a large saucepan.
  2. While the water heats up, wash your bottles with soap and water.
  3. Use tongs or a slotted spoon to carefully place all your bottle pieces into the boiling water.
  4. Make sure there are no trapped air bubbles by gently flipping the pieces.
  5. After 5 minutes or so, remove the pieces and let them air dry.


If boiling water is not your cup of tea, then try using your dishwasher instead.

Most dishwashers even have a setting for sterilizing. It produces super hot steam that really gets into the hard to reach places. If you plan on running the dishwasher anyway, this is a great time saver.

You should still wash the bottle with soap and water first. Make sure all the pieces are safe to use in the dishwasher, then put them in a basket where none of the pieces will slip out.

A stray bottle piece can wreak havoc if it gets down into the motor.


Perhaps you’ve heard of using your microwave to sterilize sponges. Well, you can sterilize your baby bottles too, but you need to take an extra step or two.

Microwaves work by heating up water (technically any electric dipoles), and a sponge typically already has residual water inside of it.

For the bottles to be cleaned, we need to add some water into the mix.

  1. Find a large microwave safe bowl.
  2. Put in all your bottle parts, making sure they too are made from microwave safe material.
  3. Add either 2 cups of water, or a cup each of water and white vinegar.
  4. Heat on the High setting for 2-4 minutes, depending on the strength of your microwave.
  5. The resulting steam from the boiling water and/or vinegar will sterilize everything.
  6. Carefully remove all the hot pieces and let them air dry.

UV Sterilizer

A new and more expensive way to go about destroying those nasty bottle smells employs ultraviolet (UV) light and mild heating.

Until recently, the machines on the market which could do this were only large enough for a pacifier or perhaps one bottle.

Nowadays, counter-top versions are available which are capable of sterilizing multiple bottles at once.

The UV light is a higher frequency form of light, and is able to kill almost all kinds of bacteria, molds, and spores.

Simply load the machine with your washed bottles and let the magic begin.

Don’t Put The Smells On Ice

There are two edges to the Temperature Danger Zone, at 140°F and also down at °40F.

So it might seem reasonable to conclude that getting your smelly bottles cold enough will be equally effective at killing bacteria, right?

Wrong. While high temperatures can kill bacteria, cold temperatures only stop bacteria from multiplying!

Contrary to the assurances of Levi Strauss, the fad of putting smelly jeans in the freezer does little except produce cold smelly jeans.

Putting smelly bottles in the freezer will only halt the growth of new bacteria. Any funky smells or harmful pathogens will be waiting for you once they thaw out again.

Shake Away The Odors

This last method is one in which grandmothers around the world all have their own unique recipe for success.

The basic principle is to use something abrasive enough to scrape milk residue off, and small enough to fit into all the tiny crevices of hard to clean containers.

Some common choices include uncooked rice, coffee grounds, and activated charcoal powder.

  1. Take your chosen substance and pour it into the bottles.
  2. Add a few drops of mild dishwashing soap and a little water.
  3. Put the lid on the bottle or cover the top with your hand.
  4. Shake vigorously, letting the mixture scrape away and absorb any grime hiding on the inner surfaces.
  5. Dispose of the mixture and wash with soap and water as usual.

Wrapping It Up

There are plenty more ways people have figured out how to fight bad baby bottle smells.

Try one of the numerous examples listed above, or come up with your own unique method – but only after doing the necessary research beforehand so you know what you’re doing. We’re all for trial and error, but only when you know you’re not putting your little one’s safety at risk.

It’s not just about what you can do after the bottles smell terrible, there’s also lots you can do to prevent odors from coming up again in the future.

The important thing to remember is that we’re all in this battle together, and it is a battle that we can most certainly win!

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