Can You Carbonate Beer with a Soda Stream? A Risky but Effective Rescue Method
Can you use a Soda Stream to carbonate beer?
The short answer is yes.
The slightly longer answer is: Yes, but it's going to get messy if you force carbonate homebrew beer without following the strict advice below.
The Sound of Silence
Rescuing Flat Homebrew
Soda Stream machines are a classic piece of kitchen equipment. If there was one thing I was envious of my mate Molyneux as a kid, it was his soda machine. After school, we'd head to his house, eat mountains of hot toast and butter, and wash it down with homemade red fizzy. Or lemonade. It was the best.
But now I'm an adult. I've spent weeks nursing a fermenter, bottling my pride and joy, waiting two weeks for conditioning, only to crack it open expecting that wondrous sounding FITZZZ of CO2 escaping... and hearing nothing.
The sound of silence. And defeat. Or am I defeated?
A trick to fix/fizz a flat beer is to add a fresh beer to it! It's a handy rescue to be able to open a can of commercial beer and pour it into the flat beer to revive the head. But what if I don't have a spare beer? The Soda Stream starts looking pretty good, eh?
Explosive Decompression
Brave Brewers Only
So? Shall I pour my flat beer into a Soda Stream bottle, sync it with the machine, and press the bubble maker?
Only if you are a very brave brewer.
One simply doesn't stuff the gas into the bottle at an explosive rate. Soda is generally carbonated to at least twice the pressure of beer (often 30–40 PSI for soda vs 10–12 PSI for ales), so doing this can be a risky little game. Otherwise, this will happen:
Science Tip: The Physics of the Mess
Why does beer explode when soda doesn't? Water has high surface tension. Beer contains proteins (from malt) and hop compounds that lower surface tension significantly. When you inject gas violently, you create millions of "nucleation sites." In water, these bubbles pop quickly. In beer, the proteins wrap around the bubbles to form a stable lattice—a foam. In the high-pressure environment of a Soda Stream, this foam expands instantly, creating a "beer volcano" the moment you detach the bottle.
How to Do It Safely
Step-by-Step Guide
With that in mind, you may want to do your initial testing outside. Ideally, before you begin these steps your flat beer will be as chilled as possible.
Technique: The Double Chill
Don't just chill the beer; chill the Soda Stream bottle too. CO2 dissolves into cold liquid much easier than warm liquid (Henry's Law). If your beer is warm (room temp), the gas will refuse to dissolve, stay in the headspace, and force the liquid out the moment you break the seal.
- Transfer the flat beer into a genuine Soda Stream bottle. You do not have to fill it to the line—a single bottle of beer will mix with the CO2...
- Headspace is key: Do not overfill! Leave plenty of room at the top—more than you would for water. If the gas nozzle dips into the beer, it's game over.
- Connect the bottle properly. This is a must. If you do not, the beer proteins will connect with the CO2 in ways that will cause a beer explosion.
- Give the machine ONE short, firm press of gas (0.5 seconds) and then release your finger. Do not do an extended press. Such a move will greatly increase your chances of beer spillage.
- Let the newly carbonated beer 'settle' in the machine before you release the bottle from the Soda Stream. Trust me, let it sit a bit. Your bottle may be quite foamy and fizzy. Let it settle.
- Remove from the device slowly and pour your beer into a cold glass.
Why Not Just Add Sugar?
Oxidation Risks
You might be asking, "Why can't I just open the flat bottle, drop in a sugar cube, and cap it again?"
You technically can, but you risk oxidation. The moment you uncapped that flat beer, oxygen rushed in. If you recap it and let it sit for another 2 weeks to carbonate naturally, that oxygen will bind with the beer compounds, resulting in a flavor that tastes like wet cardboard or sherry.
This is why the Soda Stream method is actually superior for "rescue operations" - it is a force-carbonation method meant for immediate consumption. You are carbonating it to drink now, not to store for later.
Results & Cleanup
Post-Carbonation Care
This is the time to assess what you have done. Did it work? Did you put enough gas in? Did you put too much? (You'll have learned quite quickly if you did!)
The Taste Difference: "The Bite"
Be aware that Soda Stream carbonation bubbles are often larger and "coarser" than the fine bubbles produced by natural yeast fermentation. You may notice a sharper "carbonic bite"—an acidic tang on the tongue. This is normal for force-carbonated beverages and often fades if you let the glass sit for a minute.
Pro Tip: The fresher or more filled the CO2 Cannister is, the greater the rate of release of CO2 into the beer. So hold back on massive depresses of the button if you have a fresh gas bottle!
Remember to Clean!
Rinse off the valve of the Soda Stream with water. Beer residue can get quite icky and reduce the efficiency of the valve and impact normal making soda practices. Also, sugary beer residue is a breeding ground for bacteria—you don't want that dripping into your next glass of water.
Conditioning & Final Warning
Emergency Only
What about conditioning beer with Soda Stream? All of the above advice has been to rescue a flat beer, not as part of the consideration of carbonating a whole fermenting drum with a view to capping the newly gassed beer for conditioning.
I honestly have no idea if this would work. So, some 'google fu' tells me you can do this. This perhaps seems counterintuitive but there we go. I venture however using a Soda Stream for full carbonation is a costly way to carbonate beer. You are probably better off priming your fermenter drum with sugar and bottling. The choice, as always Dear Brewer, is yours.
Fair Warning: The Soda Stream instruction manual CLEARLY states to not use their device for anything other than making soda water. Also, check the expiry date on your plastic Soda Stream bottles. They are pressure vessels rated for a certain lifespan. Subjecting an old, expired bottle to the unpredictable pressures of beer carbonation is unwise.
You have been warned.