How do I prepare a bottle of ByHeart? Alexandra May 06, 2022 18:41 Updated Please see the mixing instructions here, or on each ByHeart can (it’s on the back!). Related articles Is it ok to give my baby ByHeart formula if I am still breastfeeding? Can I use warm water? Can I use ByHeart with Baby Breeza? What's the shelf life? Do I need to give my baby any extra water? Comments 0 comments Article is closed for comments.