Step 1: Tools and materials
You also need beer. To fill 3 crates, I bought 6 mixed cases of West Coast craft beer (2x Phillips, Vancouver Island Brewery, Granville Island, Tree, and Big Rock), which got me (three lots of) 24 different microbrews. Yum.
Step 2: Design
It occurred to me afterwards that stackable crates might be handy if you wanted multiples (e.g. for homebrewers), so I modified the plans to allow this (second figure). The SketchUp file is attached, if you want to take a closer look, or modify it further. Basically, the verticals have been made slightly longer and dropped 10 mm, so each crate has short legs that slot into the crate below. If the crates don't slot together nicely, sand the insides of the legs down a little.