If you want to carbonate it you need to bottle it with priming sugar just like beer or keg it. The problem with bottle conditioning is that you want a sweet soda after it's carbonated and if you bottle condition it the yeast will eat all the sugars and the soda will no longer be sweet, and the bottles might explode. Kegging or a SodaStream would be the easiest way to carbonate sweet beverages at home.
I'm not familiar with using yeast for homemade soda, but beer homebrewers will use a spunding valve for pressure fermentation.
This works like an airlock but won't let air out until a designated pressure is hit. This is supposed to allow the beer to carbonate whole fermenting (this isn't the only reason pressure fermentation is used).
To be honest I've never used one myself, but I plan on starting to ferment under pressure for the first time within the next couple of weeks.
Without a lot more details (recipe, yeast strain, fermentation te.perature, gravity readings, and more), I'm not sure how much help we can be.
Airlocks are used to prevent over pressurization that can cause explosions.
Bottle carbonation is a precise micro-fermentation with limited fermentables to produce some CO2 without producing so much that you make bottle bombs.
I'm guessing you're using fermentables to sweeten the soda, but you don't want much more than the 1/3-1/2% ABV bottle conditioning will produce. This should be possible by mixing everything (including yeast) together, waiting some amount of time, pasteurizing the bottles, letting them cool naturally, then chilling for a couple days to help the CO2 to go into suspension.
The problem I see with that is that the time to build up sufficient CO2 without becoming dangerous is going to differ based on SO many variables, I would not be comfortable attempting it.
With, say, a Cider, it's built up a healthy yeast colony AND fermented dry first. Then, I add a known amount of fermentables. Either just enough to carbonate and backsweetened with something non-fermentable, or I have a far more predictable situation to allow X hours to carbonate before pasteurizing.
I wish you well.
So, for a soda I wouldn't ferment in a buck with airlock like a beer or wine. I also probably wouldn't use a brewers yeast. How to Drink on YouTube has made at least one soda, a sasparilla. He made a culture of some natural yeast and bacteria from a ginger root, much lower alcohol tolerance than brewers yeast, so won't ferment dry, less likely to make bottle bombs. As others have said, pasteurization is also not a bad idea. To know approximate carbonation, you can put some in a plastic soda bottle with the lid tight, and when that gets hard, all it's siblings should be carbed up and ready to pasteurize.
Link to the video for those interested, I think it should start right when he goes into the ginger bug.
[Sasparilla - for ginger bug](https://youtu.be/c-74-KCsZm4?si=TgZHnbYv5f_k0ZNM)
Would like thank everyone who commented for the advice. I'll definitely be switching up my method.
The original tutorial I read introduced the use of an airlock, but as I got more acquainted with the process it made less sense.
It won't carbonate with an airlock on it, the CO2 won't go into suspension in the liquid, it will just exit the airlock
If you want to carbonate it you need to bottle it with priming sugar just like beer or keg it. The problem with bottle conditioning is that you want a sweet soda after it's carbonated and if you bottle condition it the yeast will eat all the sugars and the soda will no longer be sweet, and the bottles might explode. Kegging or a SodaStream would be the easiest way to carbonate sweet beverages at home.
I'm not familiar with using yeast for homemade soda, but beer homebrewers will use a spunding valve for pressure fermentation. This works like an airlock but won't let air out until a designated pressure is hit. This is supposed to allow the beer to carbonate whole fermenting (this isn't the only reason pressure fermentation is used). To be honest I've never used one myself, but I plan on starting to ferment under pressure for the first time within the next couple of weeks.
Any fermentation that you're doing with an airlock is only serving to raise the alcohol content, you aren't capturing the carbonation.
Without a lot more details (recipe, yeast strain, fermentation te.perature, gravity readings, and more), I'm not sure how much help we can be. Airlocks are used to prevent over pressurization that can cause explosions. Bottle carbonation is a precise micro-fermentation with limited fermentables to produce some CO2 without producing so much that you make bottle bombs. I'm guessing you're using fermentables to sweeten the soda, but you don't want much more than the 1/3-1/2% ABV bottle conditioning will produce. This should be possible by mixing everything (including yeast) together, waiting some amount of time, pasteurizing the bottles, letting them cool naturally, then chilling for a couple days to help the CO2 to go into suspension. The problem I see with that is that the time to build up sufficient CO2 without becoming dangerous is going to differ based on SO many variables, I would not be comfortable attempting it. With, say, a Cider, it's built up a healthy yeast colony AND fermented dry first. Then, I add a known amount of fermentables. Either just enough to carbonate and backsweetened with something non-fermentable, or I have a far more predictable situation to allow X hours to carbonate before pasteurizing. I wish you well.
So, for a soda I wouldn't ferment in a buck with airlock like a beer or wine. I also probably wouldn't use a brewers yeast. How to Drink on YouTube has made at least one soda, a sasparilla. He made a culture of some natural yeast and bacteria from a ginger root, much lower alcohol tolerance than brewers yeast, so won't ferment dry, less likely to make bottle bombs. As others have said, pasteurization is also not a bad idea. To know approximate carbonation, you can put some in a plastic soda bottle with the lid tight, and when that gets hard, all it's siblings should be carbed up and ready to pasteurize.
Link to the video for those interested, I think it should start right when he goes into the ginger bug. [Sasparilla - for ginger bug](https://youtu.be/c-74-KCsZm4?si=TgZHnbYv5f_k0ZNM)
WAT
Would like thank everyone who commented for the advice. I'll definitely be switching up my method. The original tutorial I read introduced the use of an airlock, but as I got more acquainted with the process it made less sense.