Homebrewing Blog and Resource

The hobby of homebrewing beer

Carbonator Cap

I’ve probably looked at the carbonator caps in the brew shop 100 times and thought “I’d really like to try that”. This week, we finally turn dreams into reality and we test out the Carbonator Cap on my American Blonde Ale.

Have you ever had a beer finish primary and wonder if it’s really done?

Have you ever thought, “How is this beer going to taste when it’s fully carbonated?

Maybe you wanted to take a half gallon of porter and add some pie spice to it to see how that would taste.

All of those questions and ideas can be resolved with the Carbonator Cap.

The premise of the Carbonator Cap is that you can draw off a small amount of still beer from the fermentor and put it in the plastic bottle. I used a cleaned out 2 liter soda bottle for this experiment. I applied pressure from a CO2 source and purged the air from the bottle a few times.

Once the beer is chilled, I used the Carbonator Cap and applied between 10-20 PSI of head pressure and shook it up gently.

The agitation helped to drive the CO2 into the solution pretty quickly and we were sampling carbonated within moments.

Bottom line:

The Carbonator Cap allows you to understand how the finished beer is going to taste without waiting to carbonate an entire keg’s worth or wait two weeks for yeast to eat priming sugar to carbonated your beer.

You can also use the Carbonator Cap as a way of transporting some beer cheaply from your kegs to another location.

Using the 2 litter soda bottles, you can take that beer anywhere, like the beach, places where glass is frowned upon.

You can put carbonated beer in the bottle add some CO2 to maintain the carbonation and off you go. Unlike a growler where you have to rely on the some of the residual CO2 from the beer to keep the pressure up.

If you don’t have a full on draft setup at your house, you can still use the Carbonator Cap.

Using a standard ball lock fitting, you can get CO2 injectors that operate off of small 16g CO2 cartridges.

Something like this from MOREBEER.

With this injector, you can easily carb up a bottle of brew for sampling long before the bottle’s naturally carbonate themselves with priming sugar.

I thought the Carbonator Cap was pretty easy to use.

Now, I only wish I had gotten one a lot sooner.


Check out some beer bottle capper machines. You can read more on the 52brews site.


Brewers Ledger Product Review


English Ordinary Bitter Tasting and Notes


  1. Another awesome video, thank you for taking the time to post these. Do you guys do many homebrewing recipe reviews?

  2. Neighbor Jeff

    I just got a stainless steel carbonation cap that also had a small hose barb on the non-ball-lock post side. Like this: https://www.brewhardware.com/product_p/carbonatorssbarb.htm

    The post works with liquid and gas quick disconnects, so not only can you use that to carbonate, you can hook up a cheap aquarium pump to the other side to help clean your draft lines. Pretty sweet.

  3. Hi Steve – we have not done many homebrewing recipe review but we can. Send one over if you’d like our opinion.

  4. Thanks Jeff – that is pretty sweet. Let’s have a sour beer tasting!

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