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carboy caps



I just discovered the versatility of carboy caps for closed transfer.  I'm usually the last one to the party, some of you may have tried them and set them aside for better methods.  If you have let me know. At 2-3 bucks per cap and 20 some bucks for a cane its not a lot.

Transfer carboy to carboy:  2 caps with 2 ss canes inserted in the big hole of the carboy cap.  canes connected with tubing.  no clamps needed.  blow thru sterile filter to start siphon or suck air from the lower carboy (I didn't do it this way cause I'd likely pass out but 'they' say it works) .  Its a much slower transfer than a 1/2" autosiphon but its peaceful and closed.

Transfer carboy to keg:  1 cap with 1 ss cane with tubing connected to liquid out black ball connect.  blow thru the filter.  it transfers. calibration stick for carboy tells you when you need to stop.  connect gas in ball lock without tubing to release pressure or open & twist the pressure release valve in the lid. I did both.

A liquid-liquid keg jumper to sanitize and CO2 blanket at the same time keeps your kegs closed.  Yes it gets all the starsan.  Add a gas in connector without tubing to the keg to ease the pressure.

Ferment:  carboy cap with thermowell in the big hole, blowoff tube on the small teat.

transfer from chilled kettle:  1/2" silicone tubing fits good over the large hole of the carboy cap.  but you want to hold it there and it doesn't leak even with a pump.  If your pumping you will  oxygenate like never before.  Sadly, it cant be measured with my equipment. Don't forget to remove the small carboy teat cover or it will end up in the woods.  And it makes a noise on exit.

If I could figure a way to pitch yeast without opening anything would be great.  Maybe a Nalgene bottle with a funnel tip into the big teat of the carboy cap?  More thought required. 

I don't like the blowing thru a sterile filter so I have a CO2 purge kit on its way from Williams brewing to stop that.  The sterile filters always manage to get wet somehow and rendered useless and at 5 dollars that gets old.

the 'universal caps" on some websites wont fit a threaded neck acid carboy.  that one is special.  make sure it says 6.5 gallon threaded neck.  the 5 gal caps are pretty easy to snap on & off.  The 6.5 gal are a bee-otch at first but just need to get 'broken in'.



Grandmaster Brewer
Oct 4, 2013
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Thanks for the review KernelCrush.  Very informative.



The co2 purge kit fits the small teat of the carboy cap perfectly and pushes the beer.  Carboy caps can keep you closed from BK to glass.


The stainless oxygenation wands fit these carboy caps too.  If you've lost a few of the vinyl covers for the spouts like I have  they are McMasterCarr #091113 for the small ones and 031661 for the large.  Your color choices are black.  For the cost of a replacement carboy cap you can get a bag of 100.  They have white FDA versions, they are on the same catalog page at twice the money.