Has anyone fermented (primary) with saflager 34/70 @ 40f temp? Our fermenting chamber is picky and is around 40-43. We can move it, but we really don't want to since it is 15 lbs. I'm thinking it might be super slow starting.
That is quite low for W-34/70. I don't think I've ever fermented it below 48 F, and my instinct is that 40 F will be too low, and that the yeast won't ferment. If they do actually start chugging along, I would be concerned that the yeast would fall out earlier than you want and you may be left with some fermentation artifacts like diacetyl and acetaldehyde in the beer.
Some lager yeasts will do 45/46F (I believe the 34/70 strain is one of them.) But 40 id also be worried about. If you can do 45 I think you could get it to work with a large pitch and a long diacetyl rest once the beer is 2/3rds complete. (though you may try it. If you pitch in the low 50s, heat from fermentation, may keep its internal temp higher than ambient by enough. )
The growth rate of brewing yeast (s. cerevisiae for ales and s. uvarum for lagers) is temperature dependent, and monotonic in the region commonly used for brewing. The table below is constructed from data using this paper:
Walsh, R. M., and P. A. Martin. "Growth of Saccharomyces cerevisiae and Saccharomyces uvarum in a temperature gradient incubator." Journal of the Institute of Brewing 83.3 (1977): 169-172.
Optimum - Is the temperature that allowed for the fastest yeast growth. (Above and below this temperature growth and fermetation slows)
Half - is the temperature at which growth rate (and fermentation rate) is half of optimum.
Zero - Is the temperature at which no growth or fermentation was observed.
s. uvarum (lager yeast) s. cerevisiae (ale yeast)
Optimum 29°C / 84°F 33°C / 91°
Half 17°C / 63°F 19°C / 66°F
Zero ~5°C /~40°F ~5°C /~40°F
Hey Princeofthepoint. That is awesome to hear. I think ours was just too cold, we are using a True brand fridge that was free. And we think the gauge and thermometer might be less that accurate. But now we are solid