Brewing in low ambient temperatures

[SenorAnon]

I'm moving to a cooler part of Australia, and was hoping to do brews in a shed that's not heated or insulated. The daytime temperatures over winter are typically between max's of 10 to 15c and lows of -5 to 0c. I don't mind if the brews take much longer to ferment, but I am concerned that I might put the yeast to sleep, and the higher temps won't be significant enough to wake them up again. Is this going to be an issue?

 

[VikeMan]

Yes, that's going to be an issue. You're going to need to find a way to keep the active yeast in (or at least close to) normal fermentation temperature ranges.

 

[AlexKay]

There are lager yeasts that will do fine at 10 C, but that's about as low as you can go. And large temperature fluctuations wouldn't be good even if you were warmer.

The thermal mass of the beer will level things off, and a blanket thrown over the fermenter might be all you need. Do some trial runs with the fermenter full of water, and make lots of temperature measurements, and see what you have to work with.

 

[kevin58]

I would (and do) take advantage of those cooler winter temperatures to make lagers. Your daytime high's are pretty much ideal and for those overnight lows you can use a heating belt or something similar with an Inkbird to hold them there.

 

[BrewnWKopperKat]

FWIW: the anecdotal stories I have read on fermenting at "ambient" temperature (aka absolutely no additional temperature control) seem to involve a basement with a extremely stable temperature range (±1 maybe ±2) over a week or two.

 

[CascadesBrewer]

I'm moving to a cooler part of Australia, and was hoping to do brews in a shed that's not heated or insulated. The daytime temperatures over winter are typically between max's of 10 to 15c and lows of -5 to 0c. I don't mind if the brews take much longer to ferment, but I am concerned that I might put the yeast to sleep, and the higher temps won't be significant enough to wake them up again. Is this going to be an issue?

Do you have electricity in the shed? It can be fairly cheap and easy to add heating to a fermenter. I have a seedling mat + heat controller combo I got off Amazon here in the US for around $30 USD. I suspect you can find something similar. You might have to play around a bit to figure out how much insulation is needed. The coldest my lower level gets is around 15C, and with a sleeping bag I should be able to keep that at 25C.

 

[SenorAnon]

There are lager yeasts that will do fine at 10 C, but that's about as low as you can go. And large temperature fluctuations wouldn't be good even if you were warmer.

The thermal mass of the beer will level things off, and a blanket thrown over the fermenter might be all you need. Do some trial runs with the fermenter full of water, and make lots of temperature measurements, and see what you have to work with.

Ah, a blanket would be a good start. I forgot that the yeast is generating heat as it works. So it's not that I am doing the work on my own. I could even use bubble wrap as insulation. I was already planning to do that to insulate the shed's roof.

FWIW: the anecdotal stories I have read on fermenting at "ambient" temperature (aka absolutely no additional temperature control) seem to involve a basement with a extremely stable temperature range (±1 maybe ±2) over a week or two.

I ferment with ambient temperatures in Melbourne, Australia. I generally don't brew in summer, but autumn, spring and winter our temperature range is 5-25c. And I live on the lower floor of a brick apartment building so I can generally hit that 18c band on the tub if I avoid pitching on the hotter or colder days.

I was hoping to continue that in the country.

Do you have electricity in the shed? It can be fairly cheap and easy to add heating to a fermenter. I have a seedling mat + heat controller combo I got off Amazon here in the US for around $30 USD. I suspect you can find something similar. You might have to play around a bit to figure out how much insulation is needed. The coldest my lower level gets is around 15C, and with a sleeping bag I should be able to keep that at 25C.

I have solar panels and an old 12v battery, which probably isn't up to doing heating overnight. However ... I heard someone propose an idea of 'storing thermal mass' in anticipation of a temperature change as a way to be more efficient in the use of solar power. So maybe if I rig up a system to heat the fermenter to 20c as the sun sets it'll be enough to get the thing through the night with enough insulation.

There's a bit to think about here, but it might be possible to do this quite cheaply without adding too much infrastructure to justify it.

 

[Deadalus]

Are you off the grid perhaps? All it takes is a seedling heating mat and a temp controller in a normally heated room temperature home, even if the fermenter is in an unheated basement. That's $45-50 (US). The gains you get from temperature control are well worth it. Brew outside if necessary but bring it inside to ferment.

The heating mats I think are generally about 20 watts.

 

[BeerHolic]

A single bed electric blanket wrapped around fermenter could work. I think they use about 50W.
Used to use one quite successfully before I had temp controlled fridge for fermentation.