Making up a feed — and the four places the published guidance does not agree.
Nine feeding pages on this site, and not one of them told you how to actually make up a powdered formula feed. This page is the act: the never-do list first, then the method quoted step by step from the sources that publish it. Then the four places those sources genuinely disagree — the water temperature NHS publishes for everyone and the FDA publishes only for higher-risk babies, whether bottles must be sterilised, how long a made-up feed may be kept, and which tap water to use.
The things the sources say never to do.
This section is first on the page on purpose. These are not this page’s opinions — every one is quoted from the source that publishes it, and unlike the disagreements further down, no source dissents on any of them.
Making up a powdered feed, step by step.
Quoted from the source that publishes each step, not reworded. The two sources run the same order — clean hands and surface, water in first while it is hot, then the powder, then shake — and differ on one thing, the water temperature, which is the first disagreement below.
- Clean the surface and your hands firstFDA: “Wash hands with soap and water before preparing infant formula.” and “Clean work surfaces, such as countertops and sinks with soap and water… Do not place feeding items directly in the sink, because germs in sinks or drains could contaminate these items.” NHS step 3 and 4 say the same: “Clean and disinfect the surface you are going to use.”Source: FDA / NHS (Making up baby formula)
- Boil fresh water, then let it cool — and watch the clockNHS: “Fill the kettle with at least 1 litre of fresh tap water (do not use water that has been boiled before). Boil the water. Then leave the water to cool for no more than 30 minutes, so that it remains at a temperature of at least 70C.” This is the step the two authorities scope differently — see the first disagreement below.Source: NHS (Making up baby formula)
- Water goes into the bottle first, while it is still hotNHS: “Always put the water in the bottle first, while it is still hot, before adding the powdered formula.” and “Double check that the water level is correct.”Source: NHS (Making up baby formula)
- Add the exact amount of powder the pack saysFDA: “Add the exact amount of formula listed on the container.” NHS: “Loosely fill the scoop with formula powder, according to the manufacturer’s instructions, then level it using either the flat edge of a clean, dry knife or the leveller provided.” The AAP gives the ratio most powdered formula uses: “1 scoop of powder to every 2 fluid ounces of water” — with the warning that scoops differ by product.Source: FDA / NHS / AAP HealthyChildren
- Cap it and shake, rather than stirFDA: “Carefully shake the capped bottle rather than stirring the mixture.” NHS step 10: “Cover the teat with the cap and shake the bottle until the powder is dissolved.”Source: FDA / NHS
- Cool it under cold running water, then test it on your wristNHS: “It’s important to cool the formula so it’s not too hot to drink. Do this by holding the bottle (with the lid on) under cold running water.” then “Test the temperature of the formula on the inside of your wrist before giving it to your baby.” FDA: “test the formula’s temperature by putting a few drops on the inside of your wrist. It should feel warm, not hot.”Source: NHS / FDA (both, independently)
- Know the clock before you start feedingFDA: “Use prepared infant formula within 1 hour from start of feeding and within 2 hours of preparing it.” That is the figure this page’s tool below is built on.Source: FDA (Help Prevent Cronobacter Illness)
The four places the published advice splits.
Each side is quoted from the source that publishes it, with that source’s own scope attached. Nothing here is averaged into a single rule, because averaging two different scopes produces a rule that neither source publishes.
1. The water temperature: one universal rule, one conditional one
This is the sharpest split on the page, and it is a split about who the rule is for — not about the number. The number is the same on both sides.
Boil fresh tap water, cool “no more than 30 minutes”, mix while hot. NHS gives the reason: “Water at 70C or more will kill any harmful bacteria.” No group is carved out.
“if your baby is less than 2 months old, was born prematurely, or has a weakened immune system, you may want to take the following extra steps to prepare your formula with hot water.” The FDA’s default is the opposite: “In most cases, it is safe to mix powdered infant formula following manufacturer’s instructions.”
2. Sterilising: until 12 months, or not necessary
“It’s important to sterilise all your baby’s feeding equipment, including bottles and teats, until they’re at least 12 months old.” NHS also rules out relying on a dishwasher: “Putting feeding equipment through the dishwasher will clean it but it does not sterilise it.”
“For most healthy, full-term infants, it is not necessary to sterilize bottles or nipples, especially if they are washed in a dishwasher.” The AAP attaches its own scope to its own advice; it does not claim this holds for every baby.
3. How long a made-up feed may be kept
| Question | FDA — publishes a figure | NHS — publishes no figure |
|---|---|---|
| From the start of feeding | “Use prepared infant formula within 1 hour from start of feeding…” | no hour figure published; “If there is any made-up formula left in the bottle after a feed, throw it away.” |
| From preparing it | “…and within 2 hours of preparing it.” | not published by this source |
| In the refrigerator | “Use refrigerated formula within 24 hours.” | no hour figure published; NHS advises making up feeds one at a time |
| Standing at room temperature | no hour figure published | no hour figure published |
4. Which tap water
“Most municipal tap water is safe, but use cold water from the faucet. Warm tap water may contain softener salt that can pull impurities from pipes.” If bacteria in the water is a community concern: “bring water to a rolling boil for 1 minute and then cool it to room temperature before using.”
“Use freshly boiled drinking water from the tap to make up a feed. Do not use artificially softened water or water that has been boiled before.” The reason differs from the AAP’s: NHS is managing bacteria and mineral content, the AAP is managing what the pipes contribute.
One named exception, published by NHS
NHS publishes a case where the 70 °C rule is deliberately departed from, and it is the pack that governs:
- Anti-reflux formulaNHS: “Some manufacturers of anti-reflux formula recommend making it up at lower temperatures than are usually recommended. Otherwise it may get lumpy.” NHS’s instruction for that case: “Follow the instructions on the pack or speak to a health professional for advice.”Source: NHS (Types of formula milk)
When to use it, and when to throw it away.
Enter the time you prepared the feed, and this writes out the FDA’s two published keep-by points as clock times — 1 hour from the start of feeding and 2 hours from preparing — plus the separate 24-hour refrigerated window. It reads nothing but the time you type. It does not decide anything about your baby, and it will not invent the room-temperature limit neither source publishes.
FDA. The clock this tool counts down from the prepared time.
FDA. A separate clock that starts when feeding starts — not when the feed is made.
FDA, for a feed you refrigerate immediately because you are not starting it right away. NHS publishes no hour figure here and advises making up feeds one at a time.
Neither source publishes one. The tool will say so rather than show a number.
The same thing, on one card.
Print it and leave it where the feeds happen. It restates what the sources above publish — not a schedule, and not a set of numbers to hit.
| Surface and hands | clean the counter, wash your hands — do not stand items in the sink |
|---|---|
| Water | freshly boiled, cooled no more than 30 minutes (NHS) — or per pack and pediatrician (FDA scope) |
| Order | water into the bottle first, while hot, then the powder |
| Powder | exact amount on the pack · only the scoop that came with it |
| Then | cap and shake · cool under cold running water · test on your wrist |
| Never | microwave · extra powder · extra water · a feed left over from a feed |
| From preparing it (FDA) | use within 2 hours |
| From start of feeding (FDA) | use within 1 hour |
| Refrigerated (FDA) | use within 24 hours |
| Room temperature | no hour figure published by either source |
| Question for the care team |
Method restated from NHS (How to make up baby formula; Sterilising baby bottles; Types of formula), AAP HealthyChildren (How do I mix and serve infant formula; Forms of Baby Formula) and the US FDA (Help Prevent Cronobacter Illness). This card is a reminder of what those sources publish, not an instruction to hit a time.
What people ask before the first feed.
Every quotation above is taken from one of these.
Published by DadYolked · Updated October 2, 2026 · Editorial standards and corrections · The baby feeding hub · Bottle feeding, step by step. Guidance on this page is restated from the cited sources and is general information, not medical advice for your baby; your care team’s instructions override it. This page is not medically reviewed and does not diagnose anything.