Baby bottles and teats: choosing and sterilising

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How many bottles and teats do I need?

This will depend on how many times the baby is fed.

• Newborn babies generally feed between 10 and 14 times in 24 hours, with feeds becoming less frequent as they grow.
• If exclusively bottle-feeding, whether formula or expressed milk, four to six bottles and teats is a good starting point.
• If bottle-feeding is planned once a day, only one bottle might be needed.

What bottle size will I need?

Bottles come in two sizes, small ones which hold 150mls (5 fl oz) and large ones which hold 250mls (9 fl oz).

Newborns feed little and often as their stomachs are so small, so the smaller size is more suitable.

Parents might then find they need to move onto bigger bottles as their babies grow and their milk consumption increases. Every baby is different so there isn’t a set age when this should happen. 

It’s important to follow the baby’s feeding cues and signs they need more milk. These include:

• Finishing a feed
• Seeming to want more

Which type of feeding bottle is best?

There’s no one ‘best’ brand of bottle – it depends on what works for you and your baby. One that has a simple design and is easiest to clean and sterilise is probably the best option (NHS, 2024).

Basic bottles

These are the standard bottles, often narrow and cylindrical in shape. They’ll usually come with their own teats and lids and are reasonably priced. They are readily available but it can be harder to fill these narrow-necked bottles.

Anti-colic bottles

These are pricier bottles and their design is supposed to reduce the likelihood of colic symptoms. There is no evidence that this is the case, but they may reduce wind (Maxwell et al, 2025).

Wide-necked bottles

These bottles are shorter and fatter than the basic ones, but you can put the same amount of milk in them. The wider neck can make it simpler to put formula milk powder in. These bottles can be easier to clean, but take up more space in the steriliser.

Ready-to-feed bottles

‘Ready to feed’ bottles contain formula milk that is already sterilised. These can be a convenient short-term solution for one-off or occasional use.

They are more expensive and because they are single use, they are not good for the environment.

BPA and microplastics

Since 2011, the European Commission has banned the use of Bisphenol A (BPA) in baby bottles. This was because chemicals could leach out of the plastic and be absorbed by babies. None of the bottles for sale in the UK should have BPA.

More research is needed into whether cleaning baby bottles made from polypropolyne at the high temperatures needed to sterilise them releases microplastics (iHV, 2020). 

Glass bottles

Glass bottles can be easier to clean and are longer lasting than plastic bottles (Chen and Kuan, 2014). So although more expensive to buy, they can save money in the long run.

However they are usually heavier than plastic bottles.

Which teat should I use?

Teats are made from silicone or latex. Silicone is less flexible but longer lasting than latex, which needs to be replaced regularly when it becomes sticky, cracked or shows signs of wear.

Teats vary in the width of the base and the length of the nipple. Some are marketed as being more breast-like, or as mimicking the breastfeeding experience, but there is little evidence to support this (Maxwell et al, 2025).

Consider using a teat that is more suited to paced bottle feeding. This means it will hold enough milk when held in a horizontal position, rather than having to be tipped. When a bottle has to be tipped more steeply, the milk flows faster, giving the baby less control over the pace of feeding.

Which flow rate is best?

Flow rates of teats refer to the size or number of holes in the teat. This affects how quickly milk ‘flows’ from the teat to your baby’s mouth. The main categories are slow, medium and fast, with some extra variations depending on the brand (such as extra slow).

Slow flow is generally preferable for newborns, while you’re both learning how to feed.

If the flow rate is too fast:

• it makes paced feeding more difficult
• babies have very little control over how they feed as milk flows into their mouth faster than they can swallow it
• this might make your baby cough or splutter, or struggle to keep up with the flow of the milk so it dribbles to the side of their mouth
• this could also mean they get upset, get indigestion and bring up lots of milk (NHS, 2024)
• it can lead to overfeeding (NHS, 2024)

However, some research has shown that there is a lot of variability over teats marked ‘slow’ or ‘extra-slow’ even within the same brand (Marshall et al, 2021). So you may need to try different teats to get the flow which is right for your baby.

Read more about making up a feed and bottle feeding.

How do I sterilise baby bottles, teats and breast pumps?

It is important to wash then sterilise bottles and teats after they’ve been used, to make sure any bacteria is killed before they’re used again (NHS, 2023). A baby’s immune system is not as developed as an adult’s, so they could become ill if they drink milk contaminated with bacteria.

First, wash bottles and teats in hot soapy water to clean away any milk residue. Do this with a bottle brush that you only use for this (NHS, 2023). Then sterilise the bottles and teats (details below).

Sterilising a baby’s bottles and teats until they are 12 months old will reduce the risk of infections, especially diarrhoea and vomiting (NHS, 2023).

Is a dishwasher enough to sterilise bottles and teats?

Washing bottles and teats in a dishwasher may clean them, but it won’t sterilise them. They will need to be sterilised afterwards. If using a dishwasher, make sure bottles and teats are facing down so water doesn’t collect in them (NHS, 2023).

There are three main ways to sterilise bottles and teats, below.

Cold water sterilising

Cold water sterilisers use chemicals, which are mixed with cold water, to sterilise feeding equipment. They can be bought in tablet or concentrated liquid form, which are added to cold water. They are also available as a ready-to-use sterilising solution.

Items being sterilised need to be submerged in the cold water solution for at least 30 minutes before use (NHS, 2023).

It’s important that there aren’t any air bubbles trapped in the bottles and teats when they’re under the water as this will stop them being properly sterilised. Most cold water sterilisers have a cover to make sure the bottles and teats are kept under water (NHS, 2023).

After sterlising, rinse the bottles with cool boiled water. Always use cold water sterilisers in accordance with manufacturer’s instructions, as these may vary.

Boiling

The majority of bacteria are killed at 100°C (the boiling point of water) for 10 minutes. This method is particularly useful if only sterilising occasionally as specialised equipment isn’t needed.

If this method is used regularly, some items may be damaged by the heat so may need replacing more regularly (NHS, 2023).

How to sterilise baby-feeding equipment by boiling (NHS, 2023)

• Check that the item is safe to boil.
• Bring a saucepan of water to the boil.
• Submerge the items to be sterilised in the boiling water, making sure they are completely covered. Don’t put fingers into the water – a pair of sterile tongs used just for this purpose is ideal.
• Continue to boil for 10 minutes. After 10 minutes, turn the heat off and cover the pan.
• Keep the items covered and remove them just before use.

Steam sterilising

This works on the same principle as boiling. Water is added to the sterilising unit and the water boils, creating steam that kills the bacteria.

Several different types of steam steriliser are on the market. Some steam sterilisers are used in the microwave, while others are stand-alone units that plug into the mains. Some microwave steam sterilisers can also be used as cold-water sterilisers.

How to steam sterilise baby-feeding equipment

• Follow the manufacturer’s instructions, which normally involve adding a specific amount of water to the unit and running it for a given period of time.
• The length of time can vary from one steam steriliser to another.
• Make sure the openings of the bottles and teats are facing downwards in the steriliser.
• Check the manufacturer’s instructions for information about how long items can be left in the steriliser before using them.

Self-sterilising bottles

Some parents find self-sterilising bottles are useful when using the occasional bottle or when out and about. However, there is currently no independent research to suggest that this sterilisation method is as effective as the methods above.

Sterilising breast pumps (CDC, 2024; NHS Start for Life, no date)

Wash hands before expressing milk, and always store expressed milk in a sterile container with a lid (Breastfeeding Network, 2019).

• As soon as possible after using the pump, take apart the pump kit.
• Wash all the parts that have come into contact with the breast or breastmilk (including the bottle, valves and funnel) in warm soapy water, in a clean wash basin with a clean bottle brush.
• Sterilise the parts in the same way that you sterilise bottles and teats. Sterilising after each use is especially important if the baby is less than two months old or premature.
• After sterilising, leave parts on a clean tea towel or piece of kitchen towel to air dry thoroughly.

If the breast pump has tubing:

• Replace tubing if some milk has got into it, as it is hard to clean properly.
• If there are some condensation bubbles in the tubing, turn on the pump for a few minutes until it dries.
• Check that tubing is not mouldy before each use, and replace immediately if it is.

What to do after sterilising (CDC, 2024; NHS, 2023)

• Sterilised items can be left in the steriliser or pan until needed, but the majority of manufacturers advise using or re-sterilising after 24 hours.
• Hands should be washed and dried before handling sterilised equipment.
• Sterile tongs can also be used.
• If sterilised items are taken out, the teats and lids will need to be put on the bottles immediately.
• Don’t use a tea towel to dry items, as this might transfer germs. They can be left on a clean tea towel to air dry.
• The area being used to prepare the feed or assemble the pump will need to be cleaned and disinfected, or the upturned lid of the steriliser can be used.

See our articles on preparing a feed with expressed breastmilk or formula milk. 

When should I throw away the bottle and teats?

Make sure you change the teats regularly and check them for damage. Once the baby’s teeth start coming through, they can damage teats by chewing them which is a potential hazard.

In the same way, if you notice that the baby’s bottle is damaged, scratched or cracked, it should be replaced.