For regular baking yeast, use 3 parts water, 1 part sugar, small amount of yeast. It is good to dissolve the sugar first.
Temp - don't sweat it, your yeast will activate at room temp, it's easy to kill if you go too hot.
Amount of yeast - it will multiply at a malthusian rate until it pretty well covers the surface of your container (I think if you want more CO2 over fewer days, use a shorter, wider container - not yet tested), so this doesn't matter a lot though using more at the start may kick things off and get you to "steady state" production rates faster.
Amount of sugar - using a 3:1 water:sugar (volume, assuming granulated sugar) ratio will result in the sugar being used up right about the same time as the ethanol concentration is killing off the majority of your yeast cells. Any more, you're wasting sugar. Any less, you're wasting time (having to redo it more frequently). I've done the experiments & the math behind these assertions.
Baking soda - No. Sodium ions are harder on the yeast than the pH change due to fermentation is (so I've read from reputable sources).
Temp - don't sweat it, your yeast will activate at room temp, it's easy to kill if you go too hot.
Amount of yeast - it will multiply at a malthusian rate until it pretty well covers the surface of your container (I think if you want more CO2 over fewer days, use a shorter, wider container - not yet tested), so this doesn't matter a lot though using more at the start may kick things off and get you to "steady state" production rates faster.
Amount of sugar - using a 3:1 water:sugar (volume, assuming granulated sugar) ratio will result in the sugar being used up right about the same time as the ethanol concentration is killing off the majority of your yeast cells. Any more, you're wasting sugar. Any less, you're wasting time (having to redo it more frequently). I've done the experiments & the math behind these assertions.
Baking soda - No. Sodium ions are harder on the yeast than the pH change due to fermentation is (so I've read from reputable sources).