Stuck Pumpkin Ale

[DarthGoose]

Hey guys, I made my pumpkin ale 17 days ago with the following recipe:

malt & fermentables
% LB OZ Malt or Fermentable ppg °L Late
49% 6 0 Northern Brewer Pilsen LME 36 2 Y
16% 2 0 Rahr Two-Row 34 4 ~
15% 1 13 Pumpkin, cooked 1 13 ~
8% 1 0 Brown Sugar 45 18 Y
6% 0 12 Briess Caramel 60L 34 60 ~
6% 0 12 Victory Malt 34 25 ~
Batch size: 5.2 gallons


Original Gravity
1.067 / 16.4° Plato
(1.060 to 1.070)
Final Gravity
1.021 / 5.3° Plato
(1.018 to 1.022)
Color
13° SRM / 26° EBC
(Copper to Red/Lt. Brown)
Mash Efficiency
75%

hops
use time oz variety form aa
boil 60 mins 1.0 Hallertau leaf 3.2
boil 60 mins 0.5 Willamette pellet 4.7
boil 15 mins 0.5 Willamette pellet 4.7
boil 1 min 1.0 Hallertau leaf 3.2
Boil: 3.1 avg gallons for 60 minutes


Bitterness
29.1 IBU / 6 HBU
ƒ: Tinseth
NOTE: IBU results higher due to late boil additions
BU:GU
0.44

yeast
Wyeast European Ale (1338)
ale yeast in liquid form with high flocculation and 69% attenuation


Alcohol
6.1% ABV / 5% ABW
Calories
223 per 12 oz.

misc
use time amount ingredient
boil 15 min 1 tsp Irish Moss
boil 10 min 1.5 Tbs Pumpkin Pie Spice

I hit the gravity on the nose at 1.067, pitched a healthy looking and smelling 2L starter at high krausen at 72F and cooled to 65F overnight.

Signs of fermentation were visible within six hours. Fermenter continued to cool to 63F, when I realized it dropped so far I stopped icing my swamp cooler. It warmed up about 3 degrees every 2 days until it hit 68. Airlock activity mostly stopped by day 5. Racked to secondary to get off all the trub from the pumpkin and the hops (first time using whole hops, I forgot to strain them...) at day 7, gravity 1.030, tastes like acetaldehyde.

I let it sit in secondary for 10 days, airlock bubbled intermittently but never any krausen formation. Just checked the gravity and it's still sitting at 1.030 and tastes like straight acetaldehyde with just a little pumpkin spice in the after taste.

The beer has cleared pretty nicely but I'm somewhat worried that the clarity and fact the gravity isn't moving means the yeasties have all stopped working and all this acetaldehyde isn't going to be fully converted.

 

[bigbeergeek]

hindsight is always 20/20, but there's no need to rush moving a beer after only 7 days (hops, trub, pumpkin be damned). If that beer sat on the full yeast volume for a couple of weeks the beer might have cleared (flavor-wise) much sooner.

All is not lost. Just because the gravity isn't dropping and the beer is more clear doesn't mean much in the way of "all" yeast activity. There are still thousands of yeast cells per milliliter, doing what they do, cleaning up your beer's flavors. Attenuation wise, your beer isn't dropping any more. You could always pitch another more attenuative yeast starter at high krausen, but taste the beer -- is it sweet? I always wonder if pumpkin proteins (there is nearly no convertable/fermentable starches in pumpkin) can skew hydrometer readings upward?

Give the beer a month or two in the bottles -- see how much they improve.