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How to Fill a PET Bottle with a Carbonation Cap

PostPosted: Tue Jan 05, 2016 15:44
by GrahamT
I'm going to a homebrew club meeting tonight, so it's time to fill a plastic screw cap bottle with some clear beer from the corny keg. This has proved to be really handy for when I want clear beer on arrival at a party or whatever. Suitable mainly for the odd bottle, rather than whole batches, for which you're probably better with a beer gun of some kind.

I am using (with minimal equipment):

Screw cap PET bottle
Carbonation cap from Aliexpress, under a tenner delivered
Short length of narrow, silicon tubing to reach the bottom of the bottle
3ft or so of 3/8 beer/gas line and a separate short gas line from the CO2 tank
2x ball lock disconnects, one gas, one beer
Corny keg of beer, sat long enough to have cleared down well
CO2 bottle and regulator

Step 1
Sanitise all equipment. With the keg nice and cold (it was below 8C here), check the pressure in the keg.

Step 2
Dip the small tube into the bottle, connected to the spur of the carbonation cap, and tighten the cap on. Attach the gas and set the pressure slightly above the keg pressure. Unscrew the cap a little to allow air to escape and purge the bottle with CO2 for a few seconds, and retighten. NB you can attach gas and beer disconnects to the carbonation cap.

Step 3
Remove the gas line. Attach a beer line to the keg (first) and then to the bottle. Slowly untighten the cap until beer just starts to flow in, while gas escapes from the top.

With practice, you can get minimal foam and a good fill. Slow down the flow (tighten a little) as it approaches the top, then close fully and disconnect. This 1L pour took around 2 minutes.

Step 4
Retain beer in line. Decant into glass and sup! :drink:

Step 5
Stick the bottle in the freezer for a bit and have a bite to eat.

I'm having beans on toast here, but eggs or cheese are acceptable alternatives.

Step 6
Remove bottle from freezer. Gently remove the carbonation cap with tubing and replace promptly with the original cap.


That's it, you're done! Clear beer in a bottle. :drink: :cheers:

The spur can be unscrewed from the carbonation cap for easy cleaning, especially if the tubing is hard to remove (as mine is). ;)


Re: How to Fill a PET Bottle with a Carbonation Cap

PostPosted: Wed Jan 06, 2016 08:27
With the addition of an inline tap near to the bottle it is a little easier to operate.

Re: How to Fill a PET Bottle with a Carbonation Cap

PostPosted: Wed Mar 23, 2016 16:17
by MrBoy
Just to clarify, the whole point is all the CO2 dissolves at the lower temperature? How cold do you have to get it, given that you may want to serve the beer fairly cool depending on type?