Racking

Racking is the process of moving beer, wine, or cider from one container to another without disturbing the layer of trub or spent yeast that has settled at the bottom. It is most often done with an auto-siphon or a length of tubing, drawing liquid gently from just above the sediment rather than pouring, which would stir everything back into suspension.

Brewers rack for a few reasons: moving to a secondary vessel for clearing or aging, transferring to a bottling bucket where priming sugar is mixed in evenly, or moving finished beer into a keg. Doing it with minimal splashing matters at every stage after fermentation, since beer exposed to oxygen at this point can pick up stale, cardboard-like flavors over time that were not present when it was actively fermenting.

A common mistake is racking too aggressively, letting the transfer tube stir up trub from the bottom, or letting the receiving end of the tube splash into the new vessel and introduce oxygen. Keeping the siphon's intake positioned just above the sediment and running the outflow down the inside wall of the receiving vessel, or below the liquid surface once there is enough to submerge it, keeps the transfer as gentle and low-oxygen as possible.