Originally Posted by highdesertdreams
I'm a newbie to brewing soda (or anything else).
I'd appreciate it if you could explain in a little more detail what you are talking about. I don't doubt what you say, I simply don't understand it.
Frank in AZ
The yeast consume sugar and produce alcohol and carbon dioxide (CO2). In wine you want to convert most of the sugar to alcohol and vent the CO2, unless you want champagne style carbonation. Beer you want both, and soda you just want the CO2. I refereed to alcohol as ABV, Alcohol by Volume, its a common shorthand in wine making. Yeast can only withstand particular levels of alcohol before it starts killing them. Every yeast strain has been bread to highlight certain flavors and alcohol tolerances. A champagne style yeast imparts little flavor, but can ferment up to 15-20% ABV if it has enough sugar to do so. On the opposite side, a bread yeast will impart a really distinct flavor and probably die off at a really low ABV (~8%, although I made a mead that got up near 10% with it). Wild yeast are a gamble, because who knows what you are getting. In the fermenting world people like to order strains of yeast from their local home brew stores, that way they know what they are getting. Some people still use the old styles of just letting nature take its course, or putting some fruit skin in the brew.
In soda I typically dont want much Alcohol, but I want lots of CO2. I don't have a kegging system, so I need to use yeast to get my CO2. The trick is to kill off the yeast early so they don't ferment much sugar (something I want in my soda) but late enough that they provide some carbonation. That was the essence of my question. Yooper suggested putting it in the fridge. Yeast, like any living organism, only has a particular temperature tolerance. If we stick a fermenting beverage in the fridge (or outside if you are in a cold climate) then you will kill your yeast. For soda I am going to assume that works fine. In mead sometimes you cant guarantee that you have killed all the yeast with cold temperatures. The difference is that mead ages for years, where soda is consumed in days. If I have a little bit of yeast still alive in my mead, over years the carbonation will build up and my bottles will explode. If I have a little yeast still alive in my soda, I'm just going to call it pro-biotic and pretend its good for me.
Hope that helps clarify the situation.
Cheers, and good luck on the brews!