I have been making homemade soda for longer than I have used Instructables. After scanning what people have posted here on soda making, I decided that I would post my technique. This will not save you money if you compare it to most store bought carbonated beverages. However you will have control over what you put in your body. After all, the most famous soft drink in the world won't tell you all of its ingredients, but it sure makes a great rust remover!!! On to the Instructable!!!
Step 1: Tools
To make soda you could buy a pre-made soda maker, but I did not want to have to rely on a cylinder exchange program. So, I put one together using off the shelf components.
Here is what you need:
A C02 Cylinder, mine is a 10 LB as I did not want to have to get it filled very often. 5 lbs would work too!
1/4" thick walled hose, as long as you want, but long enough to give you some freedom from the cylinder.
Disconnect - Ball lock with 1/4" barb (gas)
Hose clamps (2)
Carbonator brand PET bottler
Empty 2 Liter PET bottles
I happen to live close to Ballast Point Breweries' Home Brew Mart, so that is where I picked up all but the 2 liter PET bottles. All the pieces cost me about $250. I recommend finding a local home brew supply house to pick up all the items as they should have helpful staff to assist you in the acquisition of all the pieces and perhaps fill your cylinder or direct you to somewhere that can. It will cost less to order the big pieces online though. You don't actually have to drink any of the nasty commercial sodas to get the 2 liter bottles, family and friends should be more than happy to give you theirs!
Attach the regulator to the C02 cylinder using the instructions provided with said regulator.
Attach the hose to the regulator's outlet and tighten with a hose clamp.
Attach the Ball lock disconnect to the other end if the hose with the other hose clamp.
Following all safety precautions (i.e safety glasses, and directing loved ones to a safe distance) slowly open up the C02 canister's valve and tighten up any leaky connections.
Adjust the regulator to 30 PSI.
Your C02 rig should now be ready, on to the next step!
Step 2: Figuring Out Your Proportions
I did not want to use premade soda mixes, so I figured out to make it with 3 ingredients. They are water (that we carbonate,) juice (or other such flavor,) and sugar.
Your proportions may be adjusted to suit your taste, but I find that about 10% flavor (I love cherry soda so I use cherry juice,) and 15% sugar works out pretty well.
To make life easy, mark your 2 liter bottle with fill lines.
10% plus 15% equals 25% which leaves 75% water. As we are using 2 Liter bottles, let's stick to the metric system for our measurements. 75% of 2 liters is 1500 milliliters. That is how much water we need, so I measure out 1500 ml of water and pour it into the 2 Liter bottle.
Mark a line on the bottle at the water level with a Sharpie or other such marker and label the line "water."
Measure out 200 ml of water and pour that into the bottle, adding it to the water that is already in it.
Mark the water line with the marker, and label it "juice," or "flavor," or "flavour" for our British friends.
You could continue on and fill up another 300 ml to make 2 liters and mark that for the sugar, but I find that that line always gets worn off, so I don't bother, it is just the top to me.
YAY, we have our proportions! Lets carbonate some water!
Step 3: Carbonate the Water!
Now we are onto the carbonization process!
Fill your 2 liter bottle to the "water" line with good water. I use reverse osmosis water as my tap water is so hard it could drive nails.
Chill it. I chill it overnight.
For the sake of the Department of Redundancy Department, I shall repeat: Chill the water. Warm water doesn't carbonate.
If you haven't already put the Carbonator cap on, go ahead and do so.
Squeeze out the air in the bottle while depressing the Carbonator's valve, as the instructions that came with the Carbonator indicate. when a little water comes out, stop depressing the valve. The goal is to have no air in the bottle.
With the C02 cylinder valve open and the regulator adjusted to 30 psi, attach the ball lock disconnect to the Carbonator.
You will notice that the gauge on the regulator dips below 30 psi, then slowly raises back to 30 psi.
Shake the bottle, you will notice that the pressure dips again, and then goes back up to 30. The pressure dips because the water is absorbing the C02 when you shake it, making carbonic acid.
Keep shaking until the gauge stops dipping. This is quite a little workout, but I find that I get the most consistent carbonation with this technique.
When the gauge stops dipping, remove the ball lock disconnect and put the newly carbonated water back into the fridge. Ideally it should re-chill overnight again, though I have had success in adding the rest of the ingredients right away.
Feel good that you have not only carbonated some water, but you have also gotten a nice workout!
Step 4: Make Simple Syrup
Simple is the name of it for a reason.
To make simple syrup, boil equal parts sugar and water in an uncovered sauce pot for 10 minutes.
Make a good amount of it, as you will use it for so much more than soda. I am a crusty granola eater, so I use organic sugar, hence my simple syrup has a tan color to it. Refined sugar should yield a clear syrup, but I have never made it out of refined sugar, so I really couldn't tell you.
Store your syrup in a sealable container in the refrigerator. You will want your syrup to be cool before adding to carbonated water.
Step 5: Add Flavor and Sugar
Remove cap and with a funnel tilted to the side, add your flavor. As i mentioned before I am addicted to cherry soda, so I use cherry juice. Make sure your juice is 100% juice, as we are diluting it down to 10%.
Try to get the juice to run down the inside side of the bottle to prevent the carbonated water from fizzing too much. Fill to the "juice" line.
Add your simple syrup, again trying to slip it into the soda along the inside side to prevent too much fizzing, untill you fill it to the "top".
There will be some fizz over, but I still get better results pre-carbonating the water.
Put on the cap that the bottle came with and give a little shake to stir everything up, then toss it in the fridge for a few minutes to let the bubbles settle.
Step 6: Enjoy Your Fine Tasty Beverage and Share Your Recipie!
Taste your tasty beverage. Know that you are enjoying something that is not filled with phosphoric acid and mercury laden corn syrup. Feel free to try a plethora of flavors. I have carbonated a number of juices from concentrate, grapefruit juice from my fathers grapefruit tree, even prune juice!!! You could also flavor your simple syrup and make Italian sodas. Heck, if you are going to flavor your simple syrup, use it in your lattes. I have made no calorie soda using Organic Zero, though it doesn't make a simple syrup, it can be added as granules because it dissolves rapidly. This project also helps reuse those 2 liter PET bottles! they do have a limited useful life so be sure to recycle them after reusing them a lot. When the creases on the sides of the bottle are really noticeable, it is probably time to recycle them or re-purpose them.
Please post your own variations in the comments! Tell us how you flavored it, what proportions you used, and what non-aspartame based sweetener you used!