Be your own carbonated water manufacturer!

Enter the Carbonator Cap

In the mid 1990s, a fellow patented an invention that would turn the home carbonating game on its head, as far as water is concerned. That patent is for the carbonator cap. It’s entire purpose was to turn commonly used C02 tank / regulator rigs used for beer serving (a much simpler system than soft drink delivery systems) into a carbonation system for water, using standard 2l PET bottles (those high pressure plastic bottles all soft drinks are sold in). It’s taken a long time for this patented idea to become a product, but it started showing up in the late 1990s with limited production runs. Today, other similar devices have come out, including steel ones, but you can still buy the original Carbonator Cap. You can also build your own filling system using ball lock filling caps and tire inflation valves (though they can make everything smell like rubber).

The original Carbonator Cap

Let’s Look at the Math

Before I get into how to use the above-described system in your home, let’s look at the current ways to get soda water in your home and how much they cost — and I provide a percentage comparison to a home keg C02 system.

Becoming a Home Carbonated Water Manufacturer

So you bought (or leased, or borrowed, with deposit) a nice C02 tank. It could be a mega-sized paintball gun tank (some people claim they can get the tanks refilled for free at paintball gun places!), a 5lb, 10lb, 20lb, 30lb, or even 50lb tank. Full, it holds C02 at 900psi or higher. Because your PET bottle would explode at that pressure, you also bought a keg system regulator for the tank, one that allows you to dial up or down the pressure you fill your bottles at (these usually will regulate the pressure down, delivering 5psi to 60psi which you can adjust). You bought a simple pressurized line and ball-lock filling cap used for home and mobile beer keg systems. You bought a Carbonator Cap. And you bought your last half dozen (or so) Club Soda 2l bottles (at least for the next six months!). Here’s how it all works together:

  1. take the bottle, attach the carbonator cap to the bottle, squeezing out all the air in the PET bottle before making the cap air tight.
  2. Check your Co2 rig, you want the regulator to be set at around 35–55psi (depending how strong you want the fizz — start at 35psi and adjust after sampling your beverage).
  3. Make sure your Co2’s tank main valve is off, and your safety release lever on the regulator is in the off position
  4. Attach the ball lock cap to the carbonator cap. Some residual Co2 will make its way into the bottle, but it won’t be full, or pressurized yet.
  5. Unscrew the tank’s main pressure valve to open, then slowly move the regulator’s safety release lever to the on position to fill and pressurize your PET bottle of water (key word: slowly).
  6. Once the PET bottle is filled with pressurized Co2, start shaking the bottle rapidly. C02 will only dissolve into water it is actually touching; if you don’t shake the bottle, it will take an hour to fully dissolve into water; shaking rapidly will constantly expose new water to the Co2 “gas”, speeding up the Co2’s incorporation into the H20.
  7. Shake the bottle for about 20–30 seconds. If you listen carefully, at some point, you’ll stop hearing the “hiss” of the pressurized C02 moving from the tank to the PET bottle — at this point, your water is nearly fully saturated with all the C02 it can handle — but not quite. There’s still some oxygen and other elements of “air” in there.
  8. Optionally, you can do a second C02 introduction; flip the regulator valve’s safety latch to off, and remove the ball cap from the carbonator cap on your bottle. Slowly unscrew the carbonator cap, and you’ll release all the pressure in the PET bottle (careful, it will bubble up and can spray you if you do it too fast). Let the bubbles settle for 10 seconds, then put the Carbonator cap back on, squeezing the bottle again to remove all (most) of the air inside as you tighten it. The bottle will continue to fill with gas (C02 at this point) once the cap is on securely. Reattach the ball lock cap from your tank, and flip the safety lever on the regulator back to “on” to re-pressurize the PET bottle. Shake like crazy again for 5–10 seconds. All of this optional secondary amount will remove remaining oxygen etc from the bottle and just keep it a full h20/c02 environment, making the water even more fizzy.
Here’s a video look at the process of making carbonated water.

Some Considerations

PET Bottles are built to withstand well over 125psi (failure rate is rated at 150psi), and they are a wonder of modern engineering, but they do not last forever. Count on replacing yours every 250–500 uses. (sidenote: isn’t it amazing this product people normally use once and dispose of / recycle has such a long lifespan of usefulness?) You can prolong the life of your PET bottles by controlling how fast you pressurize them: don’t just jam the regulator’s safety lever open, but slowly do it. Ditto with releasing pressure. I’ve used bottles for as long as 500 refills, but I get a bit nervous by that point. The super safe will replace bottles every six months or so (but I’ve heard of people using the same PET bottles for years). If they fail, the worst that can happen is you’ll get a high pressurized soak of ice cold water.

Become Your Own Fancy Mineral Water Manufacturer!

About 75% of the time I make my home is a homemade version of the famed natural Seltzer Waters of Germany, which don’t have any major minerals of note. So I guess I could say I am a Seltzer Water Manufacturer. But I also make my own version of Club Soda. What is Club Soda? In short, it’s an artificial version of waters like Perrier or Gerolsteiner,

  • 1/8tsp baking soda,
  • 1/8tsp potassium sulfate,
  • 1/16tsp sodium citrate,
  • 1/16tsp calcium chloride.

Make Your Own Soft Drinks!

The beauty of being your own seltzer water manufacturer is you can also be your own soft drink maker, making them at any strength or sweetness you desire! You can buy concentrated syrups all over the place: even Ikea has some — their lingonberry syrup and elderberry syrups work great in making home soft drinks. If you visit Italian delis and grocery stores, you’ll probably find shelves full of concentrated fruit syrups (blood orange, mmmm!) that are commonly used in making Italian Sodas.



Hello there. I like espresso. And coffee. And photography. And cocktails. And topical news. And espresso.

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Hello there. I like espresso. And coffee. And photography. And cocktails. And topical news. And espresso.