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Stout fermentation stopped?


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#1 Chap

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Posted 11 January 2017 - 03:34 PM

Hi all

I'm currently fermenting an extract stout. Starting gravity of 1.043, with a currently 2 day stalled gravity of 1.023. I pitched 1 pack (11.5g) of S-04 yeast for a 23 litre batch and have been fermenting now for a week at 17oC.

I really want to ferment this further to obtain an abv above 4% and thought it would have a lower FG than what it is currently. So my questions are

1. Did I underpitch?
2. If fermentation has finished, will adding more yeast now affect the brew?
3. Is the temp too low?
4. Should I raise the temp?

Any and all help is greatly appreciated

#2 malt junkie

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Posted 11 January 2017 - 03:49 PM

yes under pitched, starter or 2 packets would be the go. Also aerating/ oxgen prior to pitch.

 

your where your at, so lets move on and sort it.

 

without aerating too much give to ferment a good mix to rouse the yeast, pitch a second pack of yeast if you have one on hand failing that get one and pitch as soon as your able.

 

your currently 10 points shy of anything I'd be brave enough to bottle. (flying glass is scary) 



#3 indica86

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Posted 11 January 2017 - 04:04 PM

Underpitched with a packet of yeast in a 1043 specific gravity? Interesting proposal there.



#4 LAGERFRENZY

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Posted 11 January 2017 - 04:13 PM

+1 to add another packet of yeast no matter what the other arguments. Rescue your brew first.

#5 indica86

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Posted 11 January 2017 - 04:17 PM

I'd warm it up too.



#6 Coodgee

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Posted 11 January 2017 - 04:17 PM

queue... "S04 is notorious for..."  ...   "I've never had a problem with it, take a long, hard look at your brewing practices..." etc



#7 wessmith

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Posted 11 January 2017 - 04:26 PM

Fermentis recommend around 80gms/HL pitching rate. That works out at something like 18g of yeast so you need 2 x 11g packs. Forget what the kit manufacturers and the HB shop "experts" say, just pitch the extra yeast or make a starter. Another tip, if you dont rehydrate, make sure the wort is around 20 to 23C when you sprinkle and then slowly (1C per day) bring the temp down to your desired ferment temp of 18c or so. The ferment should be all done in 3 to 4 days. A bit of yeast nutrient will always help as will good aeration as mentioned by MJ above.

 

Wes



#8 indica86

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Posted 11 January 2017 - 04:34 PM

Mr Malty says 1 packet.

 

Fermentis say "50 to 80 g/hl for ale strains"



#9 malt junkie

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Posted 11 January 2017 - 04:34 PM

Underpitched with a packet of yeast in a 1043 specific gravity? Interesting proposal there.

11.5 gm of S04  should ideally easily knock over 23L of 1043. However the caveat is ideally. Fermenting @ 17°c, what temp was the wort when pitched? what temp was the yeast when pitched? How old is the yeast? Was the wort aerated at pitch?

 

wrong answer to more than one of the above and you need to up the quantity of viable yeast to get the job done.



#10 Chap

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Posted 11 January 2017 - 04:41 PM

11.5 gm of S04 should ideally easily knock over 23L of 1043. However the caveat is ideally. Fermenting @ 17°c, what temp was the wort when pitched? what temp was the yeast when pitched? How old is the yeast? Was the wort aerated at pitch?

wrong answer to more than one of the above and you need to up the quantity of viable yeast to get the job done.


Wort was 23oC at pitch, yeast was in the fridge so 4oC give or take a few at pitch, yeast is packet and didn't get a date so unsure of age, wort was aerated but didn't get a good foam like I normally do which sounds like it's part of the problem.

Now that I have a second packet of S-04 and will pitch it tomorrow when wort comes up to 20oC, I assume not to aerate but just give it a little swirl and sprinkle the packet yeast on top?

#11 malt junkie

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Posted 11 January 2017 - 04:51 PM

Boil some water tonight (50-100ml)  cover with foil let cool till morning. In the morning mix your yeast into the cooled water, cover and let sit for 10-15min, then give it a quick mix and pitch. Best practice is to have yeast at or within a degree or 2 of ferm temp.



#12 droid

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Posted 11 January 2017 - 04:56 PM

Whoa, have you had a second opinion on the gravity reading? With a second hydro?

#13 Chap

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Posted 11 January 2017 - 05:03 PM

Whoa, have you had a second opinion on the gravity reading? With a second hydro?


No, I don't have another to compare with. The hydrometer I have is brand new (bought it the same day I brewed) and tested in water of roughly 25oC and got 1.002 which according to the little table it came with is right.

Is there anything else I can do to confirm before pitching more yeast?

#14 TwoCrows

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Posted 11 January 2017 - 06:46 PM

If it was me , raise the temp 1 or 2 degrees and stir the wort carefully.

 

1.050 and less a  11.5 g pkt is the correct pitch rate.



#15 Chap

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Posted 12 January 2017 - 06:31 AM

Thanks for all the advice everyone!

I have the wort a stir last night, raised the temp controller to 22oC, and boiled 200ml of water covered. I'll have another look tonight and if no yeast action over the course of today I'll repitch and keep you all informed of the outcomes.

Thanks again for your help

#16 MHB

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Posted 12 January 2017 - 08:32 AM

Mr Malty says 1 packet.

 

Fermentis say "50 to 80 g/hl for ale strains"

Mr Malty says a lot of thinks I would take with a grain of salt.

 

The problem is with quoting a "pitch rate" is that there is always set of conditions for that rate, you cant apply half of the information and expect ideal outcomes.

Mark



#17 damoninja

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Posted 12 January 2017 - 09:07 AM

S04 STRIKES AGAINNN
 

"S04 is notorious for..."  ...   "I've never had a problem with it, take a long, hard look at your brewing practices..." etc

 

It's been a mixed bag for me in the past when brewing kits, had "problems" with it in kits, whether it be S04 itself or some weirdness of poorly attenuating extracts. 

 

All grain however, attenuates perfectly and makes a damn nice ale. 



#18 indica86

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Posted 12 January 2017 - 09:16 AM

Mr Malty says a lot of thinks I would take with a grain of salt.

 

 

 

I was just grabbing examples. I often wonder how an online calculator can suggest the amount of viable yeast cells in a slurry of crap taken from the bottom of an FV.



#19 Droopy Brew

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Posted 12 January 2017 - 03:24 PM

If its not too late- grab some Nottingham instead of 04. even with an underpitch that yeast will eat any sugar molucule in sight and quickly. My go -to dry yeast for any malt forward beer.



#20 Chap

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Posted 12 January 2017 - 08:49 PM

I have checked again this evening, wort temp at 21oC but no further activity so repitched a pack of s-04 rehydrated in 200mL of water for 15 min then poured into the wort without aeration as discussed above. Will continue to monitor over the next few days and advise of the outcome.

If its not too late- grab some Nottingham instead of 04. even with an underpitch that yeast will eat any sugar molucule in sight and quickly. My go -to dry yeast for any malt forward beer.

Yep, too late this time, but good to know, I'll try Nottingham from the start next time to see what difference it makes.

Edited by Chap, 12 January 2017 - 08:52 PM.