How to Sterilise Baby Bottles: A Complete Guide

Why sterilising baby bottles still matters (yes, even in 2025)

It’s true – we live in a world of hand sanitisers, antibacterial everything, and dishwashers with more cycles than we’ll ever understand. But when it comes to your baby, how you sterilise baby bottles matters. Why? Because tiny immune systems need all the help they can get, especially in the first 12 months when they’re still building up defences.

Milk (especially formula) can be a breeding ground for bacteria if bottles aren’t properly cleaned. And unlike a quick rinse or even a dishwasher cycle, sterilising is the gold standard for killing off the kinds of germs that can cause tummy bugs and infections.

So whether you’re combi-feeding, bottle-feeding from the start, or expressing, this guide is here to make sterilising feel less overwhelming and more doable.

How to sterilise baby bottles: your options

There’s no one-size-fits-all method. It’s about what fits best into your routine, your space, and your baby’s needs. Here are the main methods, with pros and cons for each.

1. Steam Sterilising (Electric or Microwave)

This is the most popular option these days – quick, chemical-free, and easy.

How it works:
Steam sterilising uses high-temperature steam to kill bacteria. You can get plug-in electric sterilisers or microwave ones (just add water and zap).

Pros:

• Fast – usually takes 4–10 minutes
• No chemicals needed
• Most models hold multiple bottles at once

Cons:

• Takes up counter or microwave space
• Not all bottles or parts are microwave-safe

Tip: Always double-check that your bottles are BPA-free and labelled as microwave-safe before using this method.

2. Cold Water Sterilising (Chemical Method)

If you’re travelling, have limited space, or just want a no-fuss option, cold water sterilising might be for you.

How it works:
Sterilising tablets or solution are mixed with cold water in a dedicated container. Bottles soak for at least 30 minutes.

Pros:

• Doesn’t need electricity or heat
• Great for on-the-go or overnight sterilising
• Affordable and accessible

Cons:

• Takes longer (30 minutes minimum)
• Has a mild chlorine smell
• Needs to be changed every 24 hours

Tip: Make sure there are no air bubbles trapped inside bottles or teats – these can prevent full sterilisation.

3. Boiling

The old-school method that still works – as long as you do it right.

How it works:
Place bottles in a large pan of water, bring to the boil, and keep boiling for 10 minutes.

Pros:

• No special equipment needed
• Kills germs effectively

Cons:

• Can damage some bottles or teats over time
• Needs constant supervision (boiling water = hazard zone)

Tip: Set a timer and don’t over-boil – repeated exposure to high heat can make plastic brittle or warp teats. Consider whether glass or plastic baby bottles are right for you.

4. Dishwasher (with caveats)

Some modern dishwashers have a sterilising cycle, or reach high enough temperatures to sanitise bottles.

How it works:
Use a hot wash cycle (above 70°C), place bottles on the top rack, and use a bottle-safe basket for small parts.

Pros:

• Hands-off and convenient
• Ideal if you already run a daily load

Cons:

• Not all dishwashers get hot enough
• Still not a complete sterilisation method for newborns

Tip: If using a dishwasher, always follow up with steam or cold water sterilising for babies under 6 months.

Cleaning before sterilising: don’t skip this step

Sterilising only works if your bottles are thoroughly cleaned first. That means:

• Rinsing out any milk or formula immediately after use
• Washing with hot soapy water and a bottle brush
• Paying attention to hard-to-reach areas like teats and lids

Sterilising doesn’t remove milk residue – it kills bacteria. So think of it as step two in the cleaning process.

How long are bottles sterile for?

This varies by method:

• Steam sterilising: bottles stay sterile for up to 24 hours if the lid is kept closed
• Cold water method: bottles remain sterile in the solution for up to 24 hours
• Boiling: must be used immediately after cooling
• Dishwasher: treat as clean, not sterile, unless used in combination with another method

When can you stop sterilising baby bottles?

The NHS recommends sterilising bottles until your baby is at least 12 months old. After that, their immune system is usually strong enough to handle normal levels of bacteria, provided bottles are thoroughly cleaned.

Final thoughts: make it work for you

There’s no perfect method to sterilise baby bottles, only what works best in your home and your routine. Whether you’re steaming, soaking, or boiling, the goal is the same: protecting your baby from unnecessary germs while feeding.

Some parents go all-in on electric sterilisers. Others manage perfectly well with cold water and tablets. What matters most is consistency and cleanliness – not how fancy the method is.

And if you’re feeling the pressure, you’re not alone. You’re doing great, and this phase won’t last forever.

Sources and further reading

• NHS – How to Sterilise Baby Bottles
• Tommee Tippee – Sterilising Bottles Guide
• BabyCentre UK – Sterilising Baby Bottles
• Which? – Best Steriliser Reviews