What is spring of starter?

"Spring of starter" typically refers to a method in baking, particularly in sourdough bread making, where a small amount of mature starter (a mixture of flour and water fermented with wild yeast and bacteria) is combined with fresh flour and water to create a new batch of starter. This process helps to ensure the starter remains active and healthy for leavening dough. It can also refer to the refreshing of a sourdough starter by feeding it with new flour and water, promoting yeast activity and flavor development.