Why Do Bottle Nipples Get Clogged? – 7 Reasons and Solutions

Balint Horvath, PhD

Writer, parent, and veteran of baby feeding battles.


Have you ever wondered why bottle nipples get clogged? If you’re a parent, you’ve probably experienced the frustration of dealing with clogged bottle nipples. No matter how hard you try to keep them clean, they always end up getting blocked. In this article I’ll provide 7 reasons and solutions. 

One of the more common reasons why baby bottle nipples get blocked is because the formula isn’t mixed correctly. You’ll also find that some nipple holes are too small and sometimes thick food doesn’t go through the opening. 

Key takeaways

  • Mix your baby formula correctly in water that’s at a temperature of 158°F.
  • Wash bottle nipples thoroughly in warm soapy water after every feed. 
  • Add the right ratios of formula to water to prevent clogging. 
  • Don’t feed your baby porridge or oatmeal in a bottle. 
  • Get y-cut baby bottle nipples for thicker formula.
  • Use a pin to make the nipple hole bigger to prevent clogging. 
  • Mold growth can clog nipples. Use vinegar to remove the mold. 

1. Baby formula isn’t mixed

Baby formula is a cow’s milk that has been treated and turned into powder form to make it more suitable for babies. To make the formula, you have to scoop the right ratios of the formula into a bottle of hot water. Sometimes you may not mix the formula properly and the powder can form into a clump and block the nipple.   

Solution – Make sure you mix the formula correctly

Make sure the water that you’re adding the formula into is at a temperature of around 158°F to kill the bacteria inside the formula. The hot water will also dissolve the powder. Then shake the bottle about 10 to 15 times before cooling the milk down to ensure the formula is mixed properly. Here’s a quick demonstration of how to do it.

2. The nipple wasn’t washed properly

In some cases, you may forget to wash your baby bottle nipples after it’s been used. Or you failed to wash them properly. This will result in a build-up of formula or food that will clog the opening of the nipple.  

Solution – Wash nipples after every use 

To prevent the build-up of fat from breast milk or the powder from formula, you must wash your baby bottle nipples after every feed. You can first soak the nipples in hot water with a bit of baking soda. Then use warm soapy water to get dirt out of the crevices of the nipples.  

3. The baby formula is too thick 

Make sure you use the right ratios of formula when making your baby’s bottle. Mixing in too much formula powder can cause the liquid to become too thick which can clog the nipples.  Adding too much formula can also cause many side effects such as dehydration and fatigue.  

Solution – Use the right formula measurements 

It’s recommended that you add 1 level scoop of formula for every 2 ounces of water to prevent clogging nipples and causing unwanted side effects. 

4. You’ve tried feeding your baby oatmeal or porridge

When your baby reaches 6 months of age it’s time to start introducing him or her to solids. In this case, you may have tried putting porridge or oatmeal inside the bottle. The thickness of the food can cause the nipples to clog up because it can’t go through the opening.  

Solution – Don’t put thick food in the bottle

It’s recommended that you don’t put thick foods inside baby bottles because they can damage the nipples. Instead, place cereals and oatmeal in a small bowl and feed your baby using a spoon.  

5. The nipple is faulty

There are situations where you’ve bought baby nipples but there isn’t a hole or opening. Or the flow rate of the nipple is too low. These are signs that your baby bottle nipples have a defect where food can’t pass through them properly which is causing them to clog up. 

Solution – Buy the right nipples 

It’s essential to inspect your baby bottle nipples first before you buy them. Make sure there are no tears in the material. Consider also buying higher-brand nipples like Dr Brown’s that have various shapes like the y-cut for better flow rates for thick liquids. Here’s a video on how to choose the right level nipple for Dr Brown’s.

6. The nipple hole isn’t big enough

You may have gotten bottle nipples with a lower flow rate without realizing it. Or the hole in the nipple simply isn’t big enough. This can cause thick food to accumulate in the nipple which can clog the hole.  

Solution – Make the nipple hole bigger 

If the nipple hole isn’t big enough, you can expand it using a thick needle. Poke the needle through the exact spot where the original hole is from the inside of the nipple to make it bigger. This will improve the flow rate and prevent liquids from getting clogged in the nipple. 

7. Mold growth 

There will be times when your baby bottles and nipples will grow mold. This is a result of not washing and sterilizing your bottles correctly. Food can accumulate inside the nipples and start to ferment, causing the growth of mold and bacteria that can clog the nipple’s opening. 

Solution – Use vinegar to remove mold growth

Black or dark green spots present inside the nipples are a sign you’re dealing with mold growth. To eliminate the mold and kill the bacteria, you must clean your nipples and bottles in vinegar. Leave them to soak for 10 minutes then wash them thoroughly with warm soapy water.   


As you can see there are several reasons why your bottle nipples might be clogged. The good news is that most nipples (silicone) these days are transparent so you can see if there is anything clogging up the hole. For a comparison between the 2 most common nipples, you may want to read my article on silicone vs latext nipples.

I recommend that you clean your baby bottle nipples in a dishwasher after every feed or use the ideal nipples for thickened formula. Use the tips I’ve provided in this article to ensure you don’t ever have to deal with clogged-up baby bottle nipples again!

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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