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Standard Carboy Cap

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Standard Carboy Cap

SKU: 7044

Fits standard 3, 5, or 6 gallon glass carboys. Put a racking tube through the center spout, fit the cap over the mouth of the full carboy, then blow hard into the second hole to prime a siphon.


To use the Carboy Cap: Push a racking cane through the center tube, place on the top of your carboy, blow into the other tube, and a siphon is easily started. May also be used for blow-off when fermenting. Attach a length of 3/8" ID tubing to the hood, and run the tubing into a bucket of water. When used this way, the carboy cap takes the place of an airlock.

Note: This item is only compatible with glass carboys in 3, 5, 6 or non-acid 6.5 gallon sizes.
Details & Instructions

Additional Information

4.8 / 5.0
33 Reviews
5 Stars
4 Stars
3 Stars
2 Stars
1 Star
Makes siphoning a lot easier
Using a racking cane, I use a quick blast of CO2 to get the siphon going rather than blowing into the tube.
January 29, 2014
Invaluable multi-purpose carboy tool
I used one of these when aerating wort by puting a racking cane through it with a stone on the bottom which keeps the stone in place and keeps airborn contaminents out of the carboy. I also hook up CO2 to the small post and push beer out to help limit oxegen contact post ferment._x000D__x000D_to the previous reviewer Mark that said it is a poor design... you have your carboy handle located too high on the carboy neck, move the handle down and it will fit fine. That being said this is not as air tight as a stopper but it has more functionality and is an invaluable tool.
July 19, 2011
Decent for price
Not a tight fit but I still like to use it. I just use a zip tie to get it snug on the carboy.
May 24, 2012
Seems to be working as intended.
I am using the cap in place of an airlock with a tube going into a gallon of water to prevent a blow over. It seems to be working as intended although it is only the 2nd day of fermentation._x000D__x000D_The last batch of beer had a blow over and I am hoping this will cure that problem. _x000D__x000D_
May 26, 2012
Makes Transferring fun !!!
Like the ad says, just insert your racking cane in one hole, blow in the other, and racking to secondary is one breath away......Fun and easy......The way it should be !!.......Oh, and you can use it as a cap too........
September 24, 2012
So many ways to use it.
First got two so I could do sterile transfers, then i started replacing bung/air locks for these caps and air locks. I also toasted an oak dowel and stuck that in the center hole and now using that in a sour beer to see how it does with air exchange. FYI you can boil these too, I do lots of sours and then clean and boil the caps afterwards.
October 9, 2012
Less slip than a bung
I found that sanitized carboy bungs have a tendency to slip quite a bit when placed while wet, so I tried this out for use with an airlock and it did the job.
November 5, 2012
Perfect for transfer
I use this for transfer out of secondary, and this works perfect. Just put the racking cane in the one tube, give a short puff into the other tube, and siphoning goes like a snap. I primarily use my two carboys that I leave handles on, and i haven't had any issue with the cap fitting snug enough to siphon transfer. I prefer to use this cap instead of the auto siphon, as it's easier to position to a side and avoid siphoning up too much trub, without the outer tube of the auto siphon holding some of the beer._x000D__x000D_I have done primary in a 6-gallon carboy and found that my racking cane in the carboy cap doesn't reach all the way to the bottom and I had to switch to the auto-siphon in order to transfer the last couple inches of beer. Easily overcome, just didn't think about it before I started siphoning.
December 10, 2012
I love these caps. No more risk of pushing a rubber stopper into your fermentation vessel! Simple to start a siphon, as well as creating a blow-off. I ordered 2 of these for my primary vessels!
December 16, 2012
not good on better bottles
Works great on glass carboy. Bought for better bottle that came with starter kit. Will be getting a glass carboy for long secondary fermen- tations and this should work well with good seal. Just needed to read item descriptions better where it states about problem with the plastic carboy...Cheers
December 21, 2012
Customer Q&A
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Browse 2 questions Browse 2 questions and 3 answers
How well will this fit a one gallon carboy?
M J on Feb 7, 2016
BEST ANSWER: Hello Mike,

Thank you for choosing Midwest Supplies! That cap will not fit on a 1 gallon jug/carboy. It is designed to slip over the rounded top of a traditional carboy, and the 1 gallon fermenters do not have this style top, and they are also smaller in diameter. I hope that this helps!
Will these fit the 18.9 liter water bottles? Will you ship internationally?
R J on Feb 13, 2016
BEST ANSWER: They should fit 18.9 L bottles, but I'm sorry to say that we do not ship outside the US.

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