5 Reasons Why Baby Bottles Go Cloudy PLUS How to Stop It!

Balint Horvath, PhD

Writer, parent, and veteran of baby feeding battles.


Show me a parent who doesn’t occasionally question why baby bottles become cloudy when they’re cleaned well every time! There are a number of reasons why this happens and it’s not always because you do a bad job at washing them!

Baby bottles are prone to cloudiness when exposed to intense heat, drying cycles in sterilizers or dishwashers, and harsh cleaning agents. Hard water is another culprit for cloudy baby bottles. Washing with other dirty dishes can stain your baby bottles, resulting in cloudiness.

Key takeaways

  • Heat stress, scratches, soap scum, milk residue, and low-quality material all result in baby bottles becoming cloudy
  • Cloudy baby bottles can be prevented by using mild soap, washing after every feed, using glass instead of plastic products, rinsing in cold water, and avoiding the dishwasher
  • Plastic bottles normally discolor over time and unless they show signs of damage, they don’t need to be thrown away because of their cloudy appearance

Reasons why baby bottles are cloudy 

Plastic baby bottles are prone to going cloudy over time. While it’s not always a cause for concern, cloudiness can be avoided by minimizing the reasons that caused the problem in the first place!

1. Heat stress 

Exposing baby bottles to high temperatures is one of the most common reasons for them going cloudy. Introducing extreme heat to plastic material causes its components to react in a certain way and slowly lose their clear appearance. 

High temperatures alter the composition of molecules, making the material go soft while changing the original transparency of the plastic. Baby bottles are exposed to intense heat when placed in boiling water, washed in the dishwasher at high temperatures, or when sanitized in sterilizers. 

Avoiding high temperatures is the best way to maintain the bottle’s material composition. This can be done in the following ways:

  • Heat milk in a different container and let it cool down slightly before transferring it to the baby bottle.
  • Using lukewarm water to clean baby bottles.
  • Reducing the dishwasher wash cycle temperature. 
  • Avoiding using the microwave to heat up milk or to sanitize bottles. 

Purchasing top-quality baby bottles made with premium plastic makes them more resistant to heat stress as well. 

2. Scratches 

Scratches in baby bottles cause the plastic’s chemical properties to change and break down quicker, making it less transparent over time. 

Using harsh bottle brushes is one of the reasons the interior becomes scratched. Rough handling of baby bottles and improper storage are other reasons for scratches. 

All of this can be avoided by using brushes with soft silicone bristles and handling the bottle carefully. Knowing how to store baby bottles properly will extend their lifespan too!

3. Low-quality material 

Baby bottles and nipples made with low-quality material are more likely to lose their transparency than those made with premium plastic or other materials. Cheaper baby bottles often turn cloudy faster than better-quality products at a slightly higher cost. 

Using popular baby bottle brands often means you get a superior quality product that can handle high temperatures especially if they’re dishwasher- or microwave-safe. 

Better quality baby bottles and nipples are often scratch-resistant, giving you more life out of them. 

4. Build-up of milk residue 

Infant formula and breast milk contain fats and proteins that happily stick to plastic! What’s more, if the bottle is scratched it becomes even easier for milk residue to cling to the plastic. If this is happening to your baby bottles it won’t take long for them to lose their clear appearance. 

Incorrect washing of bottles leaves a build-up of milk residue which eventually causes cloudiness of the plastic material. Milk proteins also get clingier to plastic when exposed to heat stress, resulting in a less-than-transparent baby bottle. 

5. Soap scum

Another common reason for murky baby bottles and nipples is the build-up of soap scum. This often happens when you use harsh or low-quality cleaning agents when hand washing or using the dishwasher to clean bottles.  

Soap scum also comes about when the bottles aren’t rinsed properly after being washed. If the bottles are damaged or scratched, soap residue will stick to the plastic as well. 

How to prevent baby bottles from going cloudy 

Are cloudy baby bottles safe? Most times yes if the bottle material isn’t damaged or scratched. However, one can’t help but feel a bit icky using cloudy bottles to feed your baby while wondering how hygienic they actually are!

Knowing how to stop baby bottles from going cloudy will prolong the lifespan of these feeding items and give you peace of mind that they’re not harming your baby’s health. 

Use a mild soap 

Using a premium-quality mild soap is one of the best ways to prevent your baby bottle from going cloudy. Mild soap won’t cause the plastic composition to degrade rapidly, maintaining the transparency of the bottle as well. It’s easier to rinse gentle soap as well, preventing scum from clinging to the bottle.

Always rinse the bottles before washing them to remove milk residue. 

This video demonstrates how to wash baby bottles with Dawn dish soap.

Wash bottles after every feed

Washing baby bottles after every feed prevents milk fats and proteins from clinging to the plastic material. Regular cleaning also prevents milk residue build-up in bottles and nipples. If you don’t have time to wash them after every feed, give the bottles a good rinse and leave them in the sink until you’re ready to clean them. 

Soaking rinsed baby bottles in a solution of water and white vinegar helps to keep stains at bay and can be done after a feed. When you’re ready to wash them properly, make sure you rinse them thoroughly as vinegar does cause milk to curdle! 

Use glass bottles instead of plastic ones

Using glass bottles instead of plastic ones is a better option if you want to avoid cloudiness. Glass baby bottles don’t discolor even when exposed to high temperatures. However, soap scum and milk residue can cause temporary murkiness if the bottles aren’t thoroughly rinsed before and after a wash.

Avoid using the dishwasher 

If you’re concerned about your plastic baby bottles deteriorating faster than normal, avoid using the dishwasher especially if you use high temperatures to run a wash cycle. Certain dishwasher detergents can be too harsh for the bottles and nipples causing them to disintegrate faster. However, if you really want to keep using a dishwasher, make sure to choose some special dishwasher detergent made for washing baby bottles.

If you have to use this appliance, make sure you get baby bottles that are dishwasher-safe and always place them and their parts on the top rack for extra protection. 

Rinse with cold water instead of hot water

Rinsing with cold water instead of hot water reduces the amount of time the plastic material is exposed to high temperatures. This helps to keep the chemical properties intact and prevent cloudiness from happening too quickly.  Keep in mind that you should use bottled water or water from a water filtration system – just avoid well water if possible.

Don’t clean bottles with other utensils

It’s very tempting to clean baby bottles with other dirty utensils to save time but this often results in discoloration from stains. Dirty utensils and crockery may be coated with strong-colored food leftovers such as tomato sauce, carrot, or beetroot juices. 

Bonus method – washing your baby bottle with baby shampoo

Another method you can try which worked for me is washing your bottle with baby shampoo which is less harsh than regular dish soap. This is a handy solution as you should always have baby shampoo on stock, whenever you have a baby at home, so no need to go to the shop to look for an extra product. 🙂

Should you throw cloudy bottles away?

Throwing away cloudy baby bottles is often the only solution if they’re damaged. Otherwise, they can still be used safely when bottle-feeding your baby. In fact, in most cases, it’s normal for baby bottles to discolor over time. 

Infant formula ingredients, juices, artificial dyes in cleaning agents, and hard water deposits along with daily use are all reasons plastic baby bottles become cloudy. But, they’re still safe to use.

Discoloration or cloudiness doesn’t impact the overall performance of your baby bottle and nipples. However, if the cloudiness is caused by scratches or other damage to the bottle, you must throw it away for health and safety reasons.  


How to fix cloudy bottles is easy enough once you know the reasons for causing the problem in the first place! Preventing cloudiness or discoloration in baby bottles and nipples is simple when using my tips. 

Another similar problem you might have run into is seeing white residue on your bottle. Luckily, I’ve found some easy ways to get rid of that.

Did you know that another problem parents are suffering from is having a baby bottle that is foaming? That’s another topic I covered in a separate article.

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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