King Arthur Baking Company Glass Sourdough Crock stores and allows you to easily monitor the growth of your sourdough starter. The stainless steel lid fits loosely to allow gasses to escape and the non-reactive borosilicate glass is ideal for sourdough starter. The clear glass crock with red 0.25-inch markings helps to easily monitor if the starter has reached its highest point ready for use or if it is time for another feeding. Its 1.5-quart capacity holds enough starter for several loaves of bread. Made from borosilicate glass and stainless steel, King Arthur Baking Company Glass Sourdough Crock is free from lead, cadmium, BPA, and PFAS, and hand washable.