Help. Low gravity stout FG stalled out to high.

[itchywool]

OG 1.047 fermented vigorously for 2 days then slowed. Been three weeks and FG is 1.022 and sweet. Too sweet. What happened? Any guesses

LB OZ MALT OR FERMENTABLE PPG °L
41% 4 0 Alexander's Pale Extract 32 4
20% 2 0 Flaked Barley 28 2
20% 2 0 Pale Malt (Maris Otter) 37 3
8% 0 12 Roasted Barley - 550L 22 550
5% 0 8 Briess Chocolate 350 L 34 350
5% 0 8 Briess Crystal 80L info 29 80

3 oz. Kent goldings (60)

2 vials White labs dry english ale.

Grains mashed for 1 hour at 155 degrees at ratio of 1.5 quarts water per pound grain.

3 gallon boil. Topped off to 5.5 gallons. Aerated by vigorous shaking for 5 mintues. Fermented at steady 68 degrees.

I have roused the yeast several times.

 

[Calder]

1.047 puts you at 60% mash efficiency. That's low in my opinion, probably had a problem with fully converting the mash.

My guess is you mashed higher than 155 and got a lot of unfermentables.

 

[avidhomebrewer]

2 days of vigorous ferment? Not nearly enough. Rouse the yeast and let it go again.

 

[lumpher]

have you moved it into a warmer area to see if it kicks up again?

 

[jtakacs]

i have the same problem except mine started at .057 and is stuck at .024... i was heating the mash and got distracted - it spiked to 170 for a while. mine makes sense, this i have no idea... i'm thinking of an amalyse addition but i just tried it today and it tastes great and not overly sweet. i'll be putting it in a barrel so i think that will add some astringency and mask any cloying sweetness... it'll still be flawed, but drinkable fo'sho.