All the recipes I find are using 4 quart crockpots. I've seen them. They are "cute" and all, but hardly anything remotely practical for THIS family!
Maybe for Miss Emily's play kitchen, but I'm a 7 or 8 quart crocker myself (3 of them actually). Those little 4 quarts are barely a side-dish around here!
Not one site I've found doing the crockpot yogurt has discussed doubling the recipe. Perhaps it just doesn't lend itself to doubling. Some recipes are like that.
Has anyone made yogurt in a larger crock and had success? I'm concerned with the heating qualities being different between the smaller units and the larger ones. Anyone has personal experience or shall I count this a learning curve and just go for it? It isn't as though I couldn't affords to louse up a gallon of milk here :)