let's pile rocks for miso

one of okazaki's famous features is its miso factory. here they still make it in the traditional way, and this means putting a ridiculous amount of beans and salt and a few other other things into an enormous barrel, then piling 2 tons of rocks on top and leaving it for 2 years. after that you get your premium hacho miso soup. after the tour we had miso ramen, miso soup, miso ice cream, and miso beer. i like the way these guys think. actually, the beer didn't taste that much different from normal beer. another bizarre thing to tick off the list of things i never thought i'd try.
my big question was, where do they get all the rocks from? i mean, with all those barrels - and another storehouse next door - that's a lot of rocks. apparently the river nearby yields enough rocks to go around. it must be some poor sap's full time job to select only the finest rocks from the riverbed and haul them out.