Bottle warmers and sterilizers: what you need, and what you don't

You probably need less of this than you think

This is the category with the most gear and the least necessity, so we will start where most guides will not: a lot of parents do not need a bottle warmer, and a lot do not need a sterilizer either.

Milk does not have to be warm. Plenty of babies drink it straight from the fridge quite happily, and if yours does, a warmer is a gadget rather than a necessity. On sterilizing, CDC guidance on infant feeding items is to clean items after every use, and to sanitize daily only if your baby is under two months old, was born premature, or has a weakened immune system. A dishwasher run hot with a heated drying or sanitizing cycle already does that job.

So before you buy anything here, read do you need a bottle warmer? and bottle sterilizer vs dishwasher. Between them they will save a good number of readers a hundred dollars and a square foot of counter, and we would rather do that than sell you both.

How the category actually divides

There are four distinct machines here, and they do different jobs:

• A bottle warmer brings a cold bottle up to feeding temperature. The good ones control the temperature rather than blasting steam. Our warmer picks lead with the one that fits nearly every bottle shape.
• A sterilizer kills germs on clean items using steam. The version worth paying for also dries, because wet parts are the actual daily annoyance. The sterilizer round-up explains why the drying cycle is the feature.
• A bottle washer washes, sterilizes and dries in one machine. It is expensive and large, and it earns its place only if you are running a lot of bottles every day. The washer picks say who that actually is.
• A portable warmer solves warming milk in a car, on a plane or at a playground. A cheap insulated flask does the same job for a tenth of the money — see portable warmer picks.

What to buy, in what order

If you are buying nothing else, buy a microwave steam sterilizer for the first two months and a good bottle brush. That covers the period when daily sanitizing is actually recommended, costs very little, and takes no counter space when it is not in use.

Add a bottle warmer if your baby turns out to object to cold milk, or if you are exclusively pumping and reheating stored milk several times a day. Add an electric sterilizer with a drying cycle if you are exclusively pumping, because pump parts plus bottles is genuinely a lot of washing. Add a bottle washer only if you have done the first two things and still feel like you live at the sink.

Warming milk safely

Two rules, and the first one is not negotiable. Never microwave milk or formula. It heats unevenly and creates hot spots that can scald a baby's mouth, even when the bottle feels fine to your hand. Use a warmer or a jug of warm water, and always test the temperature on the inside of your wrist. The method is in how to warm breast milk.

Second: milk that has been warmed does not go back in the fridge indefinitely. CDC storage guidance gives freshly expressed milk up to four hours on a countertop at room temperature and up to four days in a fridge at 40°F, and milk left over after a feed should be used within two hours. Every number is in one table in how long can breast milk sit out?

If you use glass bottles, check the fit

Squat, wide glass bottles do not fit a lot of warmer wells, and you find that out at the worst possible time. We cover which warmers cope in bottle warmers that fit glass bottles, and the bottles themselves are in the glass bottle round-up.