Bottle warmers can provide a fast and easy way to warm your baby's formula or your breast milk. They're safer than using the microwave, which can cause uneven heating and increase the risk of burns, although bottle warmers also present risks. Unfortunately, not all bottles fit into all bottle warmers. If you're using a baby bottle that's a different size or shape than most, make sure the bottle warmer and bottle are compatible before buying.
Factors That Affect Fit
If a baby bottle has a wider than normal base, it might not fit into a standard bottle warmer, BabyGearLab.com found after testing seven name-brand bottle warmers. Using a smaller-model bottle warmer with a wider-than-average bottle could make the bottle more difficult to remove, increasing the risk of burns. Some units hold baskets that make removing bottles easier; if your bottle fits too snugly in a bottle warmer, removing the basket might make it fit better.
Bottle warmers work in several different ways. Many work by producing steam that heats the milk inside the bottle. Others use a circulating warm-water bath to heat the bottle. It can take anywhere from two to eight minutes for milk to reach the desired temperature, BabyGearLab.com reports. Most, but not all, have a safety valve that shuts off heat production once the milk reaches the desired temperature, an important safety feature.
Choosing a Bottle Warmer
Some manufacturers make both bottles and bottle warmers. If you buy a baby bottle that differs from most, buying the bottle warmer made specifically for that bottle is probably your best bet. If the bottle manufacturer you've chosen doesn't make a bottle warmer, test your bottle in the warmer before you buy. Some models are more complicated to assemble or use than others; reading reviews of specific bottle warmers can give you firsthand information from other parents on a unit's ease of use.
Bottle warmers, like microwaves, can overheat milk. In some cases, bottle warmers can cause burns. In 2010, Williams-Sonoma recalled baby bottle warmers that caused finger burns to an adult who removed a bottle from the warmer, the Consumer Product Safety Commission reports. This unit used steam to heat the bottle. When BabyGearLab.com tested bottle warmers, they found that some were messy to fill, while others overheated the milk, causing a burn risk and destroying nutrients in milk, especially breast milk.