I'm planning to brew a California common "steam" beer. I will be using a bottom fermenting lager yeast, specifically Wyeast 2112 California Lager. This is intended for a warmer fermentation, up to 68 degrees(F).

My question is, what will happen if I ferment at 70 degrees? Alternatively, I could move it outside, which would lower the average temperature, yet introduce far more variability. Bad idea? Or should I just give up and find some ale yeast?

  • If you can't control your temps to be consistently below 70, then you aren't going to have much luck with any beer styles at all, and your lagers are going to be terrible. Brew a Saison or a banana-bomb Hefe instead, if either of those appeal to you.
    – GHP
    Commented Jul 3, 2012 at 17:01
  • I've never tried a lager before, but I'd say I've had pretty good luck with my ales. I guess maybe not as much as I would have at 60-65 though.
    – Colin
    Commented Jul 3, 2012 at 17:53

2 Answers 2


Fermenting just a few degrees above a yeast strains optimum temp will not generate detrimental effects, but you could lose out on the bread and butter a particular yeast strain provides. 2112 from Wyeast can stop providing lager characteristics once the fermentation temp has surpassed 65F. With a 70F ambient temp, and keeping in mind that when fermenting your beer's temp will increase 1-2F, that puts you at 71-72F. I would say you are defeating the purpose of using 2112 at that point.

I would highly encourage you not to ferment outside. Unless you got a cooler large enough to fit your fermenter, in WI you would be talking temp variations of 20-30F throughout the day. This is not good.

If you are going to get a different yeast, I would suggest making a 'different' beer.

Alternatively, I would explore ways to control your fermentation temp indoors. One way to do this is to use a wash tub (or a 'keg' bucket), place your fermenter inside, and fill the rest of it up with ~60F water. The water will not only keep your fermenter cool, but act as a heat sink so your fermentation temp will be very slow to fluctuate in the 70F environment.

  • I've seen the heat sink method mentioned before, but I wasn't sure how sustainable that would be. If I fill a tub with 60 degree water, how long would that last until it equalizes to the ambient 70 degrees? Would I need to replace the water several times per day?
    – Colin
    Commented Jul 3, 2012 at 17:50
  • Also, can you elaborate on what 'lager' characteristics are lost above 70? And also why temperature variations are bad? I'm trying to learn as much as possible, thanks.
    – Colin
    Commented Jul 3, 2012 at 18:52
  • RE: how long until equalization, I would keep a thermometer in the tub and check it once in the morning, and once at night. Based on my limited knowledge and experience with physics calculations, it would make sense that you'll be 'freshening up' your bath once a day (based on using a 20 gallon tub). Obviously, bigger the tub, the less attention you'll have to give it.
    – hartski
    Commented Jul 3, 2012 at 19:18
  • RE: 'lager' characteristics, I would classify these as being primarily clarity and smoothness. Both of these a lager provides, and the higher your ferment temp, the more these will be lost. Though, someone else may care to elaborate a bit further. RE: temp variations, I believe the biggest losers here are the yeast. The yeast behaves differently at different temps, giving you no consistency (or control) in the development of your beer's overall profile. Happy Yeast = Happy Beer. Keep the yeast happy...and safe inside your house.
    – hartski
    Commented Jul 3, 2012 at 19:28

I have brewed Steam lager twice at 20-22°C(68-71°F) using SafLager W-34/70 which has an ideal temp range of 12–15°C (53.6-59°F). We hit FG in 4 days, and bottled 3 days later. Both times at these temps the lager was delicious, and a few brewer friends were shocked when I told them what temp it was brewed at. Steam lager can be excellent.

At the higher temps it threw off a lot of sulphury aroma during fermentation, but once it had finished an sat for a couple of days it tasted fantastic so into bottles it went.

We have also brewed the same beer starting at 20C and dropping to 8C to lager for 4 weeks. And, yes the beer was different, but both were very drinkable.

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