Look at all those bubbles! That's a wide-mouth quart mason jar and the starter is all the way up to the top lip. That's a lot of growth. Right after I feed the jar, I split it into 2. If all goes well, I'll have 2 starters to work from for those occasions when I'm doing a lot of baking. Just a few more feedings (and thin-ings) and we're on our way to dough. Lots and lots of dough.