US-05 Fermenting at 38F

[Tobor_8thMan]

Put US-05 yeast from a recent brew in a mason jar for keeping until I need the US-05 for another brew (in a few weeks).

Beverage center is 38F.

After 1 day I was very surprised to see a nice head of krausen in the mason jar. Yes, the jar has an airlock so no worries about pressure building and blowing up the mason jar.

Surprised to see any fermentation activity at 38F with the US-05 as 38F is way below the US-05 temp range.

 

[kh54s10]

I wonder if it is infected. I wouldn't think the yeast could be active at that temperature.

 

[dmtaylor]

Yeast can be active at any cool temperature above freezing. Just more sluggish. The millions of people who think fermentation can't happen in the 30s F are all quite incorrect.

 

[burntchef]

So, If yeast will do it's work at much lower temps what would be the anticipated impact on flavor when fermenting in a unconditioned space above freezing? If no one has any insight I will let you know as I am about to brew another batch of irish red with us05.
Eric

 

[BrewnWKopperKat]

With US-05, some people state that they get peach flavors when fermenting in the low 60s and upper 50s. Others state that they have no off flavors in that temperature range. Personally, I don't taste the peach off flavors in US-05.

Last winter, I brewed a couple of small batch APAs with a stable ambient temperature of around 55. The beer came out fine. I measured the wort/beer temperature when one of the first batches was fermenting & the beer/wort (one gallon batch) was a degree or two higher than ambient temperature.

How low were you going to go?

 

[burntchef]

Prolly in the 50's to start. I am trying to prolong the time the heat remains off in the bewhaus. I am still noodling a low cost fermenting chamber that will work well with my current setup. My current line of thinking involves 2" blue board box with a cube ceramic heater inside, controlled via inkbird.
Eric

 

[Vale71]

More than the low temperature what I find worrisome is that you don't mention anywhere having made any fermentables available to the saved yeast?
If the yeast is only suspended in beer residue than I wouldn't expect any visible fermentation unless there's something else there besides the yeast capable of fermenting dextrins....

 

[TheMadKing]

More than the low temperature what I find worrisome is that you don't mention anywhere having made any fermentables available to the saved yeast?
If the yeast is only suspended in beer residue than I wouldn't expect any visible fermentation unless there's something else there besides the yeast capable of fermenting dextrins....

Agreed,

OP if you didn't add any additional sugar then I would be very cautious of using that yeast. You may have a an infection of diastaticus wild yeast or something else undesirable