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Universal Carboy Cap

universal carboy cap


This Carboy Cap fits 3, 5, and 6 gallon carboys (does not fit 6.5 gallon carboys). It fits tightly around the carboy mouth, and the two openings are convenient for attaching or inserting tubes, airlocks, siphons, or racking canes. Caps for both openings are included.

More than meets the eye! Of course the Carboy Cap is a cap, and can be used as such. But the beauty of this item is its flexibility and usefulness in combination with other equipment. See our recommendations below, or engineer your own!

Starting a Siphon…

Put your racking cane into the middle hole of the cap. Then, to start the siphon, blow into the other hole. Air pressure on the liquid will force it up the racking cane, thus starting your siphon!

Capturing Yeast or Fermentation Overflow…

Want to avoid spills from a vigorous fermentation or collect top-fermenting yeast for re-use in another batch? Insert a racking cane into your carboy through the center hole of your Carboy Cap, keeping the other hole closed. Cap a small overflow vessel (like a 3 gallon carboy) and run a tube from the racking cane into the side hole on of the cap on the smaller container. Insert your airlock into the center hole of the overflow vessel’s cap.