Normally I use small mason jars to store my starters in in the fridge (I have three of them). At first, a few years ago, I kept more starter around, in a quart size jar and fed it at least 1/4 cup flour and water each week, but now that I have more practice with the starters and have a better idea of what recipes I use most regularly, I tend to keep a smaller quantity around and store them in pint size jars, for the most part. If I’m just feeding them and not planning on using them the next day or two, I feed them a small amount (a Tablespoon each of flour and water) and stir it directly in the jar, then leave it out for eight to twelve hours for wheat based starters, and only an hour on the counter for my rye sourdough, before capping and putting back in the fridge.

If I plan on using the starter to bake within the next day or two, I tend to remove it from the jar, feed it larger amounts in a bowl (to allow for easier expansion) then measure out what I need to bake and store the rest in a new, clean jar.

I haven’t had the problem of over-expansion for a long time, not since I began keeping less around and feeding it smaller amounts if not in use. If you keep a large quantity around, it will get too sour without an equally large feeding as the yeast will overpower the food. If you keep a smaller amount around, and feed it appropriately, it won’t get quite as sour which actually makes it easier to maintain, in my opinion. Your bread will still be sourdough, and you can certainly augment your recipe/proofing time, etc. based upon the amount of time allowed to proof, maintaining the dough for days in the fridge before baking, adding more starter to the dough, etc to make that specific loaf more sour, if you so prefer, without making the entire starter super sour, which in turn makes it more acidic and more prone to die.

Oh, and in regard to how I cover the starters, when they’re sitting on the counter after being fed, I tend to loosely drape over some plastic wrap or even a coffee filter (over the jars) and then I cap them with plastic caps for storage in the fridge.

I hope this answers your questions! Please let me know if you have any more! Good luck!

Best,
Sarah

Thanks!