Wine yeast is best. But I use what's at the supermarket.
I posted something about this on TPT - don't know if anyone has thought about this much. Total stab in the dark, because I'm not sure how one would operationalize the vague concept, but just a thought:
All yeasts have an aerobic phase, when they respire and undergo propagation (budding "daughter cells") to the optimal population density, given the solution environment they find themselves in (amount and structure of sugars in solution, etc.); then they undergo anaerobic fermentation.
A high pitching rate and higher temperature tends to increase the rate of fermentation, and shorten the length of fermentation - for example, most brewers consider a 6X -10x yeast replication optimal for brewing purposes - pitch too little, and the tendency is for a good many off-compounds to kick out as the yeast struggles to reach its proper population density; overpitch, very little aerobic respiration takes place, and this can cause its own problems down the road - one of which is the absence
of some desired fermentation components, such as the esters of a good many ales.
Anyway, all yeasts have a non-linear fermentation profile - depending on pitching rate and temp, a lag time during respiration, a buildup to a maximal CO2 and ETOH synthesis from sugars, and a slowdown as yeast metabolism slows down and yeast dies off due to the presence of ETOH and absence of available sugar in solution (they undergoe "autolysis," or self-consumption, in attempting to "keep eating.")
Ale yeasts, typical saccharomyces cerevisae
, tend to higher rates, and a more rapid buildup and slowdown. In my brewing practice, which includes O2 injection and other things to encourage optimal yeast health, fermentation is fast, furious, and typically over within 4-5 days.
Lager yeasts (var. of saccharomyces carlsbergensis
), however, tend to a slower, more even ferment. Because of this, I would think, if you're doing DIY CO2, that it might be easier to dial in a more steady rate of production with lager "brewing" than when using ale yeasts. Just a thought (as I inject CO2), but has anyone thought to DIY lager yeast, in a fridge, with lines out to the tank?