The way I've seen it done is with one of those massive plastic commercial kitchen lidded containers, and a softball sized teabag of coffee sold by the restauran

The way I've seen it done is with one of those massive plastic commercial kitchen lidded containers, and a softball sized teabag of coffee sold by the restaurant supply company specifically for cold brewing like this. Then they put it in the walk in for a while to steep and sell it after a certain number of hours.