This is going to be a fun experiment that you can do at home. All you really need are 2 plastic bottles with cap, a drill, white vinegar (or lemon juice), baking soda, about 3 to 4 feet of plastic tubing (the one you also use for aquariums), a piece of paper or tissue and the liquid you want to carbonate.
First, you need to drill holes to the plastic caps of your bottles. The holes should be smaller than the diameter of your tubings and not more otherwise the CO2 that should carbonate the drink would be released through those holes.
Next, cut the tip of the tubings diagonally. This way of cutting will make it easier to squeeze into those tight holes. Now insert them to the caps and close the bottles. Make sure one of the tip of the tubing would go all the way down 1 bottle while the other tip should be a few inches down from the cap only (it shouldn’t touch the vinegar when you add it in later).
Add the liquid you want to carbonate in one bottle with the tip of the tubing going all the way down.
On one bottle you add 1/3 the height with vinegar or lemon juice. Don’t close the cap in just yet. Now on your piece of paper or tissue, add about 3 teaspoons of baking soda then fold the tissue over it. Gently put the tissue with the baking soda in the bottle with vinegar then immediately seal it with the cap.
At this time the baking soda and vinegar mixture will start to react but the reaction won’t be as rapid because of the paper. If you just add the baking soda straight to the vinegar, the reaction would make it foam over the bottle and that’s not what you want. Now that the carbon dioxide is forming, it will move from that bottle into the other bottle where your liquid to be carbonated is in.
While the carbonation is happening, make sure you shake the liquid bottle well. Keep on doing this every few seconds to make sure the carbonation is done properly. Also, it would be best, by the way, to use cold liquid or liquid that is almost freezing to maximize the result. Keep on shaking until no more carbon dioxide comes out from the tubing.
When the carbonation process is done, here’s the tricky part. Make sure you pinch the tube above your bottle of carbonated drink before you slowly open it up like you would with your favorite cola. Pinching the tube will prevent any loss of fizz and making a mess with your drink spraying everywhere. Once you safely removed the cap, you can now close the bottle again with a new cap without a hole. The other bottle with the vinegar and baking soda should be placed in a sink before you stop pinching on the tube from the carbonated bottle. While you’re in the sink, you can now release it and you’ll see more carbon dioxide would come out of it and even the vinegar or lemon juice would go out of the tubing.
With your carbonated drink, you can either drink it right away or keep it refrigerated until whenever you want to drink your refreshing home-made carbonated drink!