Every few days I prepare a new batch of hide glue. Granules of dry glue swell up as they soak up water overnight. The glue is ready for heating the following morning. I use distilled water when using hide glue to avoid minerals that can discolor the wood.
The jar sits in water heated to 140°F inside the small crock-pot. My current glue pot is a small, inexpensive crock-pot that keeps the water at just the right temperature.