Introduction: Home Carbonation System for Water, Beer, and More

By
About: PhD Student and Home Brewer. Think your place is to small to brew? I currently home brew in a 350 sq ft apartment that also houses my wife and 2 dogs.

Thanks to all who voted. This instructable won Runner Up in the 2017 First Time Author Challenge.

This project was born partly out of necessity and mostly out of wanting to build something useful (and awesome).

My wife is an avid carbonated water drinker, often going through 2 bottles a day. While carbonated water is not the most expensive thing, it can add up. I have also been craving a forced carbonation system for my home brewed beer, and who really wants to wait 2 weeks for bottle conditioning. Why not kill two birds with one stone?

This system is perfect for home carbonation of water, beer, wine, or pretty much any liquid you can think of.

Step 1: DIY Vs Commercial

One of the first question I am asked when I talked about this project is "why should I build one when there are so many commercial options out there?" (think SodaStream). Besides the enjoyment and sense of pride that comes with building things by hand, there are a few main reasons why I would choose a DIY Carbonation System over a commercial one.

Cost: It is true that DIY systems cost more up front (my build was $150 in total vs $70 for the low end SodaStream), depending on how often you use it it can save in the long run. Most of the commercial options have proprietary CO2 bottles designs, requiring replacements over refilling. SodaStream tanks are also only 14.5 oz and vary widely in cost depending on where you pick them up ($15-$40). My current setup uses a 5 lb tank, holding 80 oz, and cost $18 to refill at my local home brew supply store. And another plus; it's reusable. Winner: DIY.

Safety: Having CO2 under pressure is always a safety concern. I have no children and my dogs can't access the tank, so I have no worries about accidental tip overs. I do live in a high earthquake zone, but I have secured my tank so it is unlikely to fall. In general, as long as you are smart about turning off the tank, checking for leaks, and making sure your safety release vales work, a DIY option is no more dangerous than a commercial options. Winner: Tie.

Looks & Capacity: Commercial brands come in a nice, sleek package that fit snugly on your counter top. However, I live in a 350 sq ft apartment and am lacking in counter space. My DIY system fits nicely under my sink, and since it can't be seen, I don't worry to much about it looking pretty. Winner: DIY.

Versatility: This is where a DIY system really shines. Most commercial systems warranties are voided if you you use it for anything but water. However, I built my DIY system to force carbonate beer, make cheap sparkling wine, and all kinds of carbonated soda, water, and teas. On top of that, I can adjust the carbonation for each drink, meaning my wife can have her highly carbonated water while I use a lower setting to gently carbonate my beer. I can also use this system for other things -- such as tapping a keg the right way and carbon sealing products that spoil in oxygen (hops, malts, etc.). Winner: DIY.

For me, a DIY system was a no-brainer over a commercial setup. Evaluate your needs and abilities to decide what is best for you.




Step 2: Parts and Tools

Most of my parts came from Amazon, though I did pick up a few things at local hardware stores (Home Depot, Orchards, Ace). The total cost for the required parts was $130, however total prices will vary for some of the pricier items. I have also listed some optional parts and tools to add a one-way check valve and to secure your CO2 tank.

Required:

Materials

  • Ball Lock (Gas) - $7.99 (Check that this comes with hose clamps, if not, you will need to purchase some)
  • Stainless Carbonation Cap* - $10.99
  • Dual Gauge CO2 Regulator - $39.99 (regularly $43.99)
  • 5 lb CO2 Tank - $64.99
  • Gas Tubing - $0.49/ft (make sure this fits your regulator and ball lock barbs, mine where 5/16" ID)
  • Thread Tape (Gas) - $3.49**
  • A Plastic Bottle that has contained a carbonated beverage (soda, fizzy water, etc.)

*A quick update on the Carbonation Cap. I have noticed after a few weeks of using that my Ball Lock does not fit snugly onto the Stainless Carbonation Cap and I can hear hissing when I shake the bottle. Consider buying a plastic one, and let me know if the seal holds better!

**As noted in the comments I refer to this tape as Teflon tape throughout the writeup. This is not Teflon tape, but in fact Thread Sealing tape used for Gas purposes. In general, this tape is yellow, however, read the packaging to make sure you are buying the proper item!

Tools

  • Wrench(s) (prefer adjustable to fit all sizes)
  • Screw Driver
  • Spray Bottle (or some other method of adding soapy water to connections)

Optional - Check Valve:

Materials

Tools

  • Wrench(s)
  • Thread Tape (Gas)
  • Scissors
  • Screw Driver

Optional - Securing Tank:

Materials

  • Ratchet Strap - $2.50
  • Ratchet Brace - $1.00

Tools

  • Power Drill or Screw Driver




Step 3: Choosing and Filling a CO2 Tank

I consider this step to be the most important as choosing which CO2 tank to buy will depending primarily on where you can get it filled and the space (inside your home) that you have available. Before purchasing a tank, it is best to call around to find a place that can fill tanks and what their requirements are. In particularly, look for home brew supply shops (shout out to Culver City Home Brewing), air supply companies (such as AirGas), welding shops, sports equipment stores, or even paintball supply stores.

Typically, these places will have one of two ways in which they refill CO2 tanks; either they refill your tank and give it back, or swap your tank out for a pre-filled one of the same size. If they refill the tank you bring in, you are likely best off buying a new tank to get the most mileage out of a it (as I did). CO2 tanks have to be re-certified every 5-years, so buying a new one with recent certification gives you many years of use. However, if the store has a swapping policy, you are best finding a used tank that is still within its certification limit. This way you don't lose your shiny new tank and can save an the initial cost to buy a tank (used tanks often run about half the price of new). For used tanks, checks Craigslist or Ebay. Some stores may even let you buy-in to their swapping system, usually at a discounted rate.

Since my local home brew store has a refill policy, I opted to buy a new tank for $65 off Amazon and have it refilled for $18.

Once you have decided on where you will get it refilled, you should evaluate the size of tank you need. Most stores will fill tanks up to 20 lbs, but check with your supplier first. If you plan on carbonating a lot of beer, using the tank to also feed a tap system, or in general have more space -- a large tank might be for you. Just remember, you will have to transport the tank to get it filled. Since my system is being built under my kitchen sink, a 5 lb tank fit perfectly and should last me, at my current use rate, well over a year.

Note on Shipping CO2 Tanks: By U.S. law, CO2 tanks are shipped empty. If you do not purchase your tank in store, you will need to find a place to get it refilled. My $18 fill cost is a bit high from what I gather online (I live in California), most people can get a 5 lb tank filled fro $10-12.

Note on "Food Grade" CO2: There is some worry about "non-food grade CO2" that might come from refilling your tank at a welding shop or paintball store. From what I gather, this is not a real issue you should contend with, but if you are concerned, get your tank filled from a brew store or restaurant supplier.

Step 4: Choosing and Connecting a Regulator

There are two primary types of CO2 regulators on the market – single and dual gauge. While a single gauge will run a few dollars cheaper, they do not allow you to see the pressure in your tank. I like having a dual gauge to monitor how much CO2 is left in my tank and plan my trips to get it refilled.

You can also buy multi-outlet regulators. These allow you to hook a single CO2 tank up to multiple output sources. If you plan on having multiple kegs attached to this system it might be worthwhile, but since I am just using this for a force carbonation system I do not need a multi-outlet regulator.

Another thing to think about is the adjustment knob. The regulator I am using has an easy adjust knob, I can fine tune my CO2 outlet PSI with just my hands, whereas some regulator require a screw driver or an inaccurate valve. While this is up to personal preference, the one I linked has great reviews and seems to work great.

Steps for Connecting the Regulator to CO2 Tank:

  1. Make sure all of your valves are in the off position. This should be apparent for your CO2 tank (else it would be leaking), however, it might be a tad more complicated for your regulator. In general -- righty tighty, lefty loosey.
  2. Clean the threads on your CO2 tank with a wet cloth. Let dry.
  3. Starting at the edge of your threads, wrap the tape around the end a few times, going in the direction of the thread. Wrapping opposite of the threads may result in the tape coming loose while tightening on the regulator.
  4. Insert the Compression ring into the Regulator Screw.
  5. Screw on the regulator by hand, then tighten using a wrench.

Step 5: Adding Ball Lock and Hose

Steps for Adding Ball Lock and Hose:

  1. Add tape to your Ball Lock threads, again following the direction of the threads.
  2. Screw on the 5/16" barb by hand, then use a wrench to tighten the rest of the way.
  3. Cut a length of hose to go from the Regulator to the Ball Lock, I choose about 6' so that it would reach from under my sink to wherever I was standing in my kitchen. Regular scissors will work, however, it can be difficult to cut.
  4. Add a hose clamp to each end of the hose, slide them back a few inches for now.
  5. Connect one end of the hose to the barb on your Regulator making sure to press the hose all the way onto the barb. Tip: If you are having trouble doing this, run the hose under hot water for 10 seconds to make it more pliable.
  6. Push the hose clamp to the end of your hose, tightening it as much as possible using a screw driver. If you feel the clamp begin to "slip" from the holes as you tighten, it is likely at tight as it will go. If it is still loose, you need a smaller hose clamp size.
  7. Repeat 5 & 6 on the Ball Lock barb.

Step 6: Testing the System and Checking for Leaks

At this point, it is very important to test your setup and check for any leaks. First, turn the knob on your CO2 to the on position. Listen for leaks (hissing) in the connection between the CO2 tank and the Regulator. Spray the connection with soapy water, and look for any bubbling of the soap. If you see bubbles, this indicates there might be a leak. Turn off the CO2 tank, and attempt to reinstall your regulator.

After fixing and leaks between the tank and the regulator, test for leaks in the hose connections. First you need to turn on your tank and adjust the outflow from your regulator. If your regulator is like mine, you will need to "burp" the regulator -- pulling and releasing the pressure release valve -- to get an accurate outflow reading. I adjusted my knob until the PSI outflow was around 40 PSI. Now, turn on the regulator outflow valve and listen for leaks at the regulator barb and at the ball lock barb. Next, spray soapy water on each connection and again check for bubbles. If you see any bubbles, try reattaching the parts and redo all checks.

Once you have assured that all connections are leak free, you are ready to use your home carbonation system. The next step will walk you through the process of using the carbonation cap.

Step 7: Carbonating a Beverage

In this example we will use an old soda bottle to show the steps for carbonating water. However, this process works with any liquid you want to carbonate. A quick note, it is best to carbonate cold liquids that do not contain any solids. Being cold allows the liquid to absorb CO2 more quickly. Having any solids in your liquid (such as pulp from orange juice, undissolved sugars) allows CO2 to attach its self to the solids, preventing it from absorbing into the liquid.

Steps for Carbonating a Beverage:

  1. Chill your water. Overnight in the fridge does wonders, but a few minutes in the freezer with a paper towel wrapped around it will do just fine.
  2. Turn on your CO2 tank and regulator, adjusting the outflow PSI to your desired amount (I use 40 PSI for water).
  3. Add water to the plastic bottle, leaving some room for air. A good rule of thumb is to never fill it more than the container would have been filled when carbonated. Note: Do not use a regular water bottle or a bottle that has not held a carbonated beverage. These containers are often not meant to hold pressure and the bottom is likely to blow out when you pressurize it. Along the same lines, bottles that have been crinkled, folded, or otherwise damaged may also burst. Make sure to use a relatively new bottle and to switch them out from time to time.
  4. Squeeze the bottle until the water is aligned with the top edge, then screw on your carbonation cap. By squeezing the bottle, we are forcing as much oxygen out of the bottle as possible. This allows the CO2 to more readily dissolve into the water.
  5. Lifting up on the bottom ring of your Ball Lock, press the Ball Lock over the Carbonation Cap. Right away the bottle should expand.
  6. Holding onto the ball lock and cap, turn the bottle upside down. This allows the CO2 to flow through the water, helping it to absorb more quickly.
  7. Shake the bottle for approximately 30 seconds, or until you see little to no bubbles flowing through the water. Little or no bubbles indicates that the water has absorbed as much CO2 as it can.
  8. Turn the bottle right side up and, lifting the bottom ring of the Ball Lock, remove the ball lock from the carbonation cap.
  9. Remove the carbonation cap and enjoy.

Step 8: Store Bought Carbonated Water Vs Home Carbonation System

In the video I attempt to show the difference in carbonation between a store bought bottle (the first pour), a bottle that has been carbonated once (second pour), and a bottle that has been double carbonated -- carbonate it once, release carbonation by unscrewing the carbonation cap, and than carbonated again (third pour).

As you can see in the video, the store bought carbonated water holds is bubbles in the glass longer. However, the double carbonated water has a very similar carbonation level and flavor added as the store bought. My wife swears double carbonating is better and makes it taste like store bought, however, I prefer a single carbonation when I do flavored waters or teas.

The great thing about this system is you can experiment for yourself, and see what level of carbonation works best for you.

In terms of storage length; if you leave the carbonation cap on the water it will stay easily carbonated for a few days. Once its removed and replaced with a normal cap, the carbonation tends to disappear slowly. I still think it taste great recapped the next day or two, but after that its tends to be pretty flat.

Step 9: Optional: Add a One-Way Check Valve

A problem I noticed when using the basic system is that when I removed my ball lock from the bottle, I would often get whatever liquid I was using back into the hose. While this isn't a problem for water, I didn't want to have to remove and wash the hose line every time I carbonated tea, wine, or beer. To circumvent this issue, I added a one-way check valve about 6" from the Ball Lock. Not only does this prevent liquids from going back into the rest of the line, but provides a shorter amount of tubing I need to sanitize before force carbonating my beer.

Many of the steps involved in adding a check valve are the same as putting the system together. With that in mind, I won't go into as much detail as before.

Steps for Adding a Check Valve:

  1. Wrap all threads with tape, using the procedures listed in previous steps.
  2. Tighten the barb connections onto the check valve.
  3. Determine where in your line you want the check valve to go. I wanted mine close to the ball lock, to prevent to much cleaning, but not so close that it got in the way. I choose approximately 6" from the ball lock.
  4. Cut the hose at your desired location.
  5. Add hose clamps to both sides of the cut portion.
  6. Align your check valve with the hose and attach the hose to the barbs. Make sure the arrows (showing flow) are pointing towards your ball lock.
  7. Tighten the hose clamps over the barbs.
  8. Test for flow and check for leaks.

Step 10: Optional: Secure the CO2 Tank

I live in a high earthquake area, and was wanting to make sure my CO2 never fell over and broke. To do this, I added a simple system; a ratchet strap and ratchet strap brace. To install I screwed the brace into my cabinet, thread the ratchet strap through, and tightened it to my CO2 tank. Nothing fancy, but it has done its job and the tank has not fallen over.