The Difference Between Powder, Concentrated Liquid, and Ready-to-Use Formulas

You've finally chosen a brand of formula for your baby, but there's still one more decision to make: Should you use powdered, concentrated liquid, or ready-to-use formula?

"All three preparations are the same from a nutritional standpoint," says Jennifer Shu, MD, co-author of Heading Home With Your Newborn. "The choice you make will be based on personal preference and cost."

There's a lot to consider when deciding between powdered versus liquid formula. Read on to compare the cost, convenience, and preparation of each kind of formula.

Comparing Powder vs. Liquid Formula

The main difference between powder and liquid formulas is the consistency. In addition, you must always mix powder formula with water. Some liquid formula is ready-to-use, while others are concentrated, which you must dilute with water.

Powder formula

Powder formula comes in a canister with a little scoop and in little packets for travel. It must be mixed with water before feeding it to your baby.

Powder formula is the most economical formula on the market, but it can be constipating to some babies, Dr. Shu says. (That may be due to mixing errors, though, rather than the formula itself.) And you'll need to lug along safe, clean water with the powdered formula when you hit the road.

Powder formula is not more filling than liquid formula. However, mixing errors can cause you to give calorically dense or diluted formula, which could result in under or overfeeding (with regard to calories given) or electrolyte abnormalities.

Concentrated liquid formula

You pour concentrated liquid formula from a container. It is more expensive than powder formula but less messy to prepare. You still need to add some water to it before you give it to your baby, so bring a water bottle if you're going to be out and about.

Ready-to-use formula

Ready-to-use formula is the most convenient type of formula. It's rich and thick, and you don't need to add water to it before feeding. Of the three preparations of formula, though, ready-to-use is the most expensive.

How to Choose Powder vs. Liquid Formula

Choosing the right formula for your baby usually comes down to a personal preference. Considerations most parents and caregivers consider include budget, time commitment, and their baby's risk factors.

Powder baby formulas are the most economical; however, unlike liquid formulas, powder formula is not sterile. This could result in a baby getting an infection from a germ in the powder formula.

According to the Centers for Disease Control and Prevention (CDC), babies at greatest risk of sickness from powder formula contamination include:

• Newborns under 2 months old
• Premature infants
• Babies with weakened immune systems

Some parents use powder formula as an everyday feeding method but use a liquid formula when they travel or go out.

How to Use Powder and Liquid Formula

Always follow the package directions for how to mix and feed infant formula. Most formulas follow the same instruction to avoid confusion. However, never presume they are the same, and always follow directions exactly. Over- or under-mixing infant formula can result in dehydration or too much or too little weight gain.

In addition, regardless of whether you use a powder or liquid formula, always follow excellent sanitation guidelines, including the following from the CDC:

• Clean and sanitize baby bottles and all parts.
• Before preparing a bottle, clean surfaces with soap and water and wash your hands.
• Avoid setting formula scoops on the counter.
• Close formula containers immediately after use.
• If your baby is at higher risk for infection, mix powder formula with boiling water, then cool to room temperature (test the temperature on the inside of your wrist before offering it to your baby).

Never microwave a bottle because it can heat the formula unevenly. Instead, warm a bottle by placing it under warm water or in a bottle warmer.

Powder formula preparation

Mix the powder formula with water according to the package directions. According to the American Academy of Pediatrics (AAP), this is usually one scoop of powder for every 2 ounces of water.

Some people mix each bottle as needed, while others prepare enough for the entire day and refrigerate it until use. While this may save time in the long run, keep in mind storage guidelines so you're less likely to waste leftovers. Unused prepared formula can be kept refrigerated for 24 hours. After that, it must be thrown out.

Liquid concentrate formula preparation

Like powder formula, most brands of liquid concentrate have the same mixing directions. According to the AAP, these instructions are usually to mix the same amount of liquid concentrate with water. So, for example, if you want to end up with a 4-ounce bottle, you would mix 2 ounces of liquid formula with 2 ounces of water.

If you mix a day's worth of formula, you can keep mixed liquid formula in the refrigerator for up to 48 hours. The same applies to opened ready-to-use formula: Discard unused refrigerated formula after 48 hours.

If your baby doesn't finish a bottle—whether it's powder or liquid formula—never reuse the bottle or mix it with more formula later. That's because your baby's saliva gets introduced into the formula during feeding and can cause germs to grow, which could make your baby sick.