Does the water for formula need to be heated?

One of the most common practical questions about formula feeding is:
"Does the water have to be warm or is it okay to offer the baby a cooler bottle, especially if that's more comfortable for her?"

The key difference is between:

• water temperature when you MIX the powder

• the temperature of the bottle when the baby DRINKS it

Below is an overview of expert recommendations and how to turn them into a feasible daily routine.

Why is hot water insisted on at all?

Powdered infant formula is not sterile . It can occasionally contain bacteria such as Cronobacter (formerly Enterobacter sakazakii ) and Salmonella , which in rare cases can cause serious infections in infants. That is why international guidelines emphasize three pillars of security:

1. Hygiene – clean hands, clean bottles and pacifiers, proper sterilization.

2. Safe water – drinkable, boiled if necessary, used properly.

3. The right water temperature when mixing the powder - ≥ 70 °C is most often recommended precisely to reduce the risk of bacteria in the powder.

Feeding Bottle with Temperature Sensor – Wide Neck, Anti-Colic, Silicone

Basic recommendations: how to prepare formula as safely as possible

Numerous health institutions and professional bodies suggest a very similar, “conservative” protocol for preparing powdered formula:

1. Use fresh drinking water (tap or suitable bottled water).

2. Boil the water .

3. Leave it to cool for no longer than 30 minutes , so that the temperature remains around 70 °C or higher .

4. Pour the required amount of water into a sterile bottle.

5. Add the correct number of scoops of powder, close the bottle and shake well.

6. Then cool the bottle (under a cold water tap or in a bowl of cold water) until it is safe to drink.

7. Ideally, you should offer the bottle immediately; prepared formula should not sit at room temperature for longer than about 2 hours , and it is recommended to throw away any leftovers.

This regimen is particularly recommended for:

• newborns,

• premature babies,

• children with low birth weight,

• babies with chronic illnesses or weakened immunity.

Can the bottle be colder when the baby drinks from it?

Yes. Guidelines usually state that the formula for the drink should be:

• lukewarm or

• room temperature ,

and always tested with a few drops on the inside of your wrist – it should be pleasantly warm or neutral, never hot .

Many babies do well with a room temperature bottle, and some even prefer something colder than “standard lukewarm.” Some national health platforms openly state that it is okay to offer chilled formula if the baby tolerates it well.

It is important to understand:

• The temperature when MIXING the powder affects microbiological safety ;

• The temperature of the DRINK is primarily a matter of baby's comfort – as long as the milk is not ice cold straight from the fridge.

Can I skip heating and mix directly with cold water?

Here we enter the gray area and the difference between ideal and acceptable .

Strict, “safety” approach

WHO, EFSA, national food safety agencies and numerous health services still recommend mixing the powdered formula with water around 70 °C , precisely to reduce the risk of bacteria in the powder.

According to this approach:

It is not recommended to mix the powder directly into completely cold water – even if the water is declared as “suitable for infants” – especially not for younger and at-risk infants.

More flexible interpretation for healthy, full-term infants

Some newer guidelines and pediatric practices leave a little more room: for a healthy baby born at term, with strict hygiene and prompt feeding, some experts accept the use of previously boiled water cooled to room temperature during preparation.

However, even in such "more lenient" scenarios, the following applies:

• The water should be boiled at least once ,

• The formula is prepared fresh before feeding,

• Leftovers do not keep for long at room temperature.

What about "baby water" and bottled water in general?

For bottled water, including those specifically labeled as suitable for infants, guidelines typically emphasize: checking the label (mineral, sodium, sulfate levels),

• that when preparing formula, water is treated the same as tap water – i.e., it is generally boiled and cooled before mixing, especially for children under 12 months old.

When it comes to additional drinking water (without powder), that is a separate issue - many guidelines do not recommend giving additional water until about 6 months of age, if the child is fed exclusively with formula in the recommended concentration.

Practical tips if your baby prefers a “colder” bottle

If your baby clearly prefers a cooler bottle, and you want to stay as close to expert recommendations as possible, a practical compromise might look like this:

1. Prepare the formula according to the manufacturer's instructions and national guidelines:

   • fresh water,

   • boiled,

   • preferably mixing at at least ~70 °C. After mixing, cool the bottle more quickly :

   • under a stream of cold water,

   • or in a bowl of cold water, turning the bottle occasionally.

2. Test on your wrist – the bottle can be lukewarm or at room temperature , if that's more comfortable for your baby.

3. Throw away anything your baby doesn't drink within about 2 hours of preparation.

This way you combine:

• high level of safety (boiled water, freshly prepared formula),

• comfort for the baby (not necessarily "warm", but as cool as it suits them).

When should you stick to the strictest rules without compromise?

The strictest preparation rules (hot water, high level of hygiene, very fast feeding) are primarily addressed to babies who are:

• younger than 2 months ,

• prematurely born ,

• low birth weight ,

• have chronic illnesses or weakened immunity .

For this group, any deviation from official guidelines should first undergo an individual assessment by a pediatrician.

Conclusion: what is "ideal" and what is "realistically acceptable"?

• Ideally (safest scenario):
  The powdered formula is mixed with boiled water that is still hot enough (around 70°C) to reduce the risk of bacteria, then cooled in a controlled manner to drinking temperature.

• Realistically acceptable for a healthy, full-term baby (with consultation with a pediatrician):
  Use pre-boiled water , possibly cooled to room temperature, with strict hygiene and quick feeding, following the instructions on the package.

• Drinking temperature:
  It doesn't have to be "perfectly lukewarm" - the formula can be lukewarm or at room temperature, if the baby tolerates it well and is progressing normally.

Important note

This text provides general informational guidelines and does not replace individual advice from a pediatrician.
For any permanent deviation from the manufacturer's instructions and national recommendations - especially in very small or high-risk babies - it is advisable to make the decision in consultation with the responsible pediatrician.

Sources

1. World Health Organization (WHO). Safe preparation, storage and handling of powdered infant formula: Guidelines. in 2007

2. National Health Service (NHS). How to make up baby formula / How to make up a bottle feed.

3. European Food Safety Authority (EFSA). Microbiological risks in infant formulas and follow-on formulas.

4. Centers for Disease Control and Prevention (CDC). Infant Formula Preparation and Storage and Preventing Cronobacter in Infants.

5. German Federal Institute for Risk Assessment (BfR). Recommendations for the hygienic preparation of powdered infant formula. in 2022

6. Losio, MN et al. Preparation of Powdered Infant Formula: Could Product's Safety Be Improved? (Review paper on microbiological risks in PIF).

7. Raising Children Network (Australia). Infant formula: making, storing and transporting it.