# US-05 temp fail...



## L_Power (21/1/13)

Hi guys.

Using my fridge with stc-1000 for the first time, skimmed over the instructions and missed the bit about pressing the power button to store the settings.
Long story short, pitched the yeast at 22, woke up the next morning and it was at 11c..

I have put a lamp in the fridge and i'm waiting for it to rise up to 22 again before dropping it back to 18.

Should the yeast be ok or should i pitch some more?

Cheers.


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## bum (21/1/13)

She'll be fine. Just warm her up as you see fit.

You might want to consider rousing the yeast as much of it will have flocced out to the bottom. Normally people would recommend swirling the fermenter rather than risking infection by using a big spoon/etc but if a gravity sample suggests that little has occured before it got to cold you may want to rouse your yeasties with some similar implement so you can thrash some more oxygen into your brew.


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## Online Brewing Supplies (21/1/13)

US-05 should be ok at that temp, it is low but I have used it at 15C before with no problems.
Let it warm and get the yeast moving again, swirl or what ever..
If its only overnight I cant see too much dropping out.
Patience is a virtue when fermenting.
Nev


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## bum (21/1/13)

11C is okay shortly after pitch? I could never seem to keep it awake at 14C during active ferment.

My oxygenation and pitch rates have historically been fairly "close enough is good enough" though - probably the issue I had.


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## carniebrew (21/1/13)

You're doing better than me, the first time I used my stc-1000 I sat there and watched it turn the fridge on and off, giggling like a school kiddie each time.

(removed question about yeast....as my 8yo would say to me...EPIC FAIL DAD)...thanks bum.


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## bum (21/1/13)

carniebrew said:


> Which yeast did you use?


I must have been reading two threads at once :blink:. I totally thought he had specified US-05.

Ignore the bit I said about 14C.

[EDIT: ahaha, he did! It is in the title. I thought I was going loco for a moment there.]


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## L_Power (21/1/13)

bum said:


> I must have been reading two threads at once :blink:. I totally thought he had specified US-05.
> 
> Ignore the bit I said about 14C.
> 
> [EDIT: ahaha, he did! It is in the title. I thought I was going loco for a moment there.]


lol, thanks fellas. Swished it around a bit, will see how it goes.


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## GalBrew (22/1/13)

Same thing happened to me with us-05 on my first try with the STC-1000. Temps went down to around 10deg, didn't realise until the next night. Was a very estery beer. Did the exact same brew again but feremented at the right temp = not estery.


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## L_Power (22/1/13)

sitting happily on 19degrees now bubbling away.


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## Beerbuoy (23/1/13)

It'll be fine. But take it up to 20 and leave it. Don't go to 22 then drop to 18 as you mentioned earlier. Dropping back to 18 will just slow the yeast activity again.


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## JDW81 (24/1/13)

GalBrew said:


> Same thing happened to me with us-05 on my first try with the STC-1000. Temps went down to around 10deg, didn't realise until the next night. Was a very estery beer. Did the exact same brew again but feremented at the right temp = not estery.


At those temps with that yeast I think those esters are more likely to be the result of stressed yeast (possible under pitching?). While different temperatures can produce different esters with different yeasts, at 10 degrees US05 is more likely to go to sleep than throw of anything funky.


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## GalBrew (24/1/13)

JDW81 said:


> At those temps with that yeast I think those esters are more likely to be the result of stressed yeast (possible under pitching?). While different temperatures can produce different esters with different yeasts, at 10 degrees US05 is more likely to go to sleep than throw of anything funky.


I absolutely agree with the yeast stress theory. I pitched the correct amount but the temp drop occured during the growth phase (it was the first night of fermentation). After I found out, I fixed the problem and gave yeast a bit of a rouse. It all came back to life but had a strong plastic-like ester that never went away in the bottle after many months.......never falling for that one again!


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## JDW81 (24/1/13)

GalBrew said:


> but had a strong plastic-like ester that never went away in the bottle after many months.......never falling for that one again!


Plastic-like sounds to me more like the work of a brand new fermenter, not that of the yeast.


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## GalBrew (24/1/13)

Nah, had used the fermenter before and many times since. Have never had the same thing again. I only use the descriptor 'plastic-like' becasue it's the only thing I can think of to describe it. But it is definitely an ester.


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## bum (24/1/13)

Chlorine can throw plastic smells. Any relevence?


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## GalBrew (24/1/13)

Nope, don't use chlorine based stuff. PBW and Starsan for me. Water would be the same as yours Bum.


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## bum (24/1/13)

I don't know your process but if I were to add any un-boiled water to my brew then I'm fairly confident that there would be chlorine present.

For what it is worth, I've never read of any esters that are likened to plastic. Doesn't mean they don't exist but I've never heard of them if they do.


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## GalBrew (24/1/13)

I do AG BIAB. Never any unboiled water, always full volume boils. I'm sure that I am just not describing the smell/taste of this thing very well. I may have to crack open the very last bottle of this beer I have left and have another taste. I have always had trouble putting my finger on it, but the only time I have had it is when the temp bombed in the growth phase of fermentation.


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## bum (24/1/13)

Well, however it is manifesting it looks like you know what the culprit is already. At least sorta-kinda, anyway. My understanding with that yeast is that lower temps will reduce esters rather than increase them so maybe it has more to do with how the temp is raised rather than the fact it dropped? Just thinking aloud here. I'm not much of a sciency brewer, myself.


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## GalBrew (24/1/13)

I was under the impression that if you stress the yeasties out in the growth phase that they will pump out more esters. Is this right??


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## bum (24/1/13)

As I say, I'm not terribly scientifical, but I'd assume that as long as your pitch rate was adequate then it would be not much more stressful to the yeast than when you pull a smack-pack out of the fridge ready for a starter. Could be totally talking out of my me here, of course.


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## JDW81 (25/1/13)

GalBrew said:


> I was under the impression that if you stress the yeasties out in the growth phase that they will pump out more esters. Is this right??


In a nutshell that is correct, but that usually isn't the result of pitching at low temperatures. If you pitch an inadequate amount of yeast for a given beer, or pitch yeast that isn't healthy, then yes, they will potentially pump out more esters.

As far as the plastic type smell goes, I'm with Bum, and also don't think it is an ester. AFAIK esters that occur in beer all generally tend to be sweet/fruity smelling (banana, clove, bubble-gum etc) and I don't know of any that have a plastic or solvent aroma that can occur during fermentation, the base compounds and acids required for them to form aren't present in wort*.

JD

* Disclaimer: I am far from an expert on this topic, and am just applying what I know about organic chemistry, the activity of yeast and the composition of wort to formulate my hypothesis. I am more than happy to be corrected if I am off the mark.


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