What is the initial mixture of warm liquid and yeast called?

The initial mixture of warm liquid and yeast is called a yeast slurry. It is important to use warm liquid when activating yeast, as this helps to dissolve the yeast's cell walls and allows them to become hydrated. The ideal temperature for activating yeast is between 105-115 degrees Fahrenheit. Any hotter and the yeast will die, any colder and the yeast will take longer to activate. Once the yeast has been activated, it can then be added to the rest of the ingredients in the recipe.