I'm following the instructions in The Rye Baker to start a rye sour culture. After the first week of daily refreshing, it says it can be left in the refrigerator and fed once or twice a week. There are proportions for a "maintenance refresh", but no specific instructions for feeding. Am I just supposed to dump flour on top? With water?
Specifics: The first step is 70g whole-grain rye flour and 70g warm water. Daily for the next week is 70g of preceding culture mixed with equal amounts flour and water. (I'm using King Arthur Pumpernickel flour.) The maintenance refresh is 7g sour culture and 70g each of flour and water, which seems to be rather wasteful for "feeding".
In searching this site, this question got the closest to an answer, but it's asking about feeding after taking some out for bread; I'm not sure if regular not-baking-anything feeding is different, or if an all-rye culture is different.