Coldbreak Brewing Equipment CBBTC Carboy Blow Off Tube for 5-6.5 gal Glass Carboys (Pack of 3) Review (2026)

Who this blow off tube suits

This Coldbreak Brewing Equipment product is a pack of three stainless steel blow off tubes, each with a 0.375 inch outside diameter, built to fit the drilled stopper or bung used on 5 to 6.5 gallon glass carboys rather than sitting loose in an open neck. Unlike flexible vinyl tubing, a rigid metal tube holds its bend permanently once shaped, which suits brewers who want a blow off setup that does not sag, kink, or need to be repositioned each time it is used. Because it comes as a pack of three, it also works well for brewers running multiple carboys at once or who want spares on hand.

Material and fit

The tubes are stainless steel, a material that resists corrosion and does not degrade with repeated sanitizing the way some plastics can over years of reuse, and the metal's rigidity means each tube keeps whatever bend a brewer gives it rather than flexing back to straight. The 0.375 inch outside diameter is sized to seat into the same drilled stopper or bung opening used on plastic and glass carboys sized for wide mouth fermenters like a Big Mouth Bubbler or Fermonster, based on reports from brewers who have used these tubes, though the packaging specifically lists 5 to 6.5 gallon glass carboys as the intended fit.

Everyday handling and cleaning

Because the tube is metal rather than flexible vinyl, sanitizing it is generally simpler, since a stiff stainless tube can be run through a bottle brush or soaked without the tube collapsing or trapping residue in folds the way soft tubing sometimes can. The rigid shape does mean it will not conform to unusual bung sizes the way flexible tubing can, so a correct match between the tube's diameter and the stopper's drilled hole matters more here than with a compressible vinyl hose. Brewers who need to bend the tube to route foam toward a particular direction can shape stainless tubing once and expect it to hold that shape through repeated use.

How it compares with vinyl blow off tubing

Against a length of 1 inch inside diameter vinyl tubing meant to sit directly in a carboy neck, this stainless tube is thinner and depends on a drilled stopper to hold it in place, rather than sealing against the neck opening itself. That makes the two products suited to different carboy setups: the vinyl tube for an open neck carboy, and this stainless tube for a carboy sealed with a drilled bung. Against THORIUM's silicone carboy caps, which offer a soft flexible seal with spouts for tubing, the stainless tube offers a more rigid, shape holding option but depends on that separate stopper or cap to create the seal.

Verdict and who should pick something else

Choose this pack if your carboy uses a drilled stopper or bung and you want a rigid, easy to sanitize blow off tube that holds its shape and comes with two spares. Brewers whose carboys have an open neck without a drilled stopper should look at a vinyl tube sized to fit the neck directly instead, since this stainless tube is not designed to seal an open opening on its own. Anyone using plastic fermentation buckets rather than glass carboys should also check Coldbreak's separate bucket specific blow off tube, since this listing is scoped to 5 to 6.5 gallon glass carboys.

Frequently asked questions