I have a water warmer it’s set to 30/100 the water is perfect and the formula mixes better I have tried it with cold water but you have to stir more.

Hi Angela! We recommend mixing with warm water to ensure it dissolves quickly, easily, and with as little foam as possible (although foam is totally safe for baby and normal!), but ultimately, you can use whatever temperature water baby prefers. If you do heat the water before, just be sure that it cools before feeding to ensure baby's safety.