Here are step-by-step instructions on how to prepare bottles of formula.

• Boil the nipples and other bottle parts before the first use (this both sterilizes them and gets rid of the plastic flavor). You don't really have to sterilize them again after that if you had a healthy, full-term infant, as long as you have a chlorinated water supply. (Well water can be a concern. Have your water tested for safety or boil the bottles in a pot for five minutes prior to each use.) For all subsequent washings, a run through the dishwasher or hand washing in hot, soapy water will get them sufficiently clean. You'll find it's best to wash or soak bottles soon after using, as curdled milk can be difficult to scrub out.

• Wash your hands, wipe off the top of the formula can, and mix the formula exactly according to the directions (unless you're using a ready-to-use formula). Too little water can cause dehydration while too much means your baby won't be getting enough calories. If you are concerned about the amount of chlorine in your tap water, use bottled water. It isn't necessary to boil the water unless the available water supply has known problems.

• Pour the formula into the bottle. You probably think the next thing you need to do is to warm the bottle and then shake a few drops on your wrist to check the temperature, just like you've seen on TV. Wrong. In fact, unless your baby is used to a warm bottle, he probably won't care if you serve it to him at room temperature or straight out of the refrigerator, although he may get used to (and come to prefer) the bottle temperature he gets most often. Think of the advantages of a baby who will drink a cold bottle. There's no struggling to warm a bottle while holding a hungry, crying, and increasingly agitated baby and no looking for hot water while on a trip. You can put a bottle in a cooler of ice right next to your bed for nighttime feedings.

If your gourmet child insists on warm bottles, go ahead and do that little wrist ritual — if the milk feels at all hot, it is too hot. If you've microwaved the bottle to heat it, shake it well so there are no hot spots. Most experts recommend against microwaving because of the danger of hot spots, but most formula-feeding mothers end up using the microwave. If you do microwave, however, stick to plain plastic bottles; bottle liners can explode and glass bottles can crack. Never microwave breastmilk because it contains too many fragile antibodies. Put a bottle of breastmilk in a cup of warm water if you want to warm it.