Making a Yeast Starter  
Cover with sanitized foil and let ferment for a day or two.  Refridgerate if not using soon.  Optionally pour off most of the liquid, stir up the yeast slurry, and pitch cold.

Cover with sanitized foil and let ferment for a day or two. Refridgerate if not using soon. Optionally pour off most of the liquid, stir up the yeast slurry, and pitch cold.