You are taken out back behind the building to a locked cellar door nearby. After pulling out a key and unlocking it, he opens the door and leads you into an old cellar. Just as he described, it's about half-full with dry goods saved up for the orphanage.
"You generous donation, of course, will greatly fill our stocks. We'll probably be full for a while after they get back from the shopping trip. I believe now you've seen the whole place, from celllar to attic. Unless you wish to inspect the rafters?"