Fermentation stuck for good

[mfranzer]

Hey guys. Looks like my fermentation has stopped a bit early. Looking back on it I'm pretty sure I underpitched, fermented way too warm, and possibly under aerated (all of which will be fixed from now on.) I brewed the Dreadnaught recipe listed here from BYO, but I did 2.5 gallons BIAB so the total below need cut in half.

Dreadnaught clone
(Three Floyd’s Brewing Co.)
(5 gallons/19 L, all-grain)
OG = 1.084 FG = 1.021
IBU = 100 SRM = 11 ABV = 8.1%

Ingredients
16.25 lbs. (7.4 kg) American 2-row pale malt
1.25 lbs. (0.57 kg) melanoidin malt (27 °L)
8.0 AAU Warrior hops (60 mins)
(0.53 oz./15 g of 15% alpha acids)
8.0 AAU Simcoe hops (60 mins)
(0.62 oz./17 g of 13% alpha acids)
8.0 AAU Centennial hops (45 mins)
(0.72 oz./20 g of 11% alpha acids)
8.0 AAU Centennial hops (30 mins)
(0.72 oz./20 g of 11% alpha acids)
8.0 AAU Cascade hops (15 mins)
(1.6 oz./45 g of 5.0% alpha acids)
1.5 oz. Cascade whole hops (dry hops)
1 tsp. Irish moss (15 mins)
Wyeast 1968 (London ESB)
0.75 cups corn sugar (for priming)

Step by Step
This is a single infusion mash at 159 °F (71 °C) for 60 minutes. Boil the wort 90 minutes, adding hops at the times indicated in the ingredient list. Ferment at 68 °F (20 °C).


Hit my OG of 1.084, after 10 days hydrometer said 1.034, after 17....1.034. Is there anyway to restart it, or should I just throw in the dry hops and go from there?

 

[progmac]

pitching a stuck fermentation on top of an entire yeast cake is generally pretty helpful. other methods just don't seem to be effective.

 

[Obliviousbrew]

Don´t know 71C seems very high to me... maybe you just have a lot of unfermentables.

 

[jtratcliff]

got a packet of Nottingham handy?

 

[jtratcliff]

Don´t know 71C seems very high to me... maybe you just have a lot of unfermentables.

Good point! Beta Amylase denatures at those temps. That may be as low as the gravity gets.

 

[TheZymurgist]

Don´t know 71C seems very high to me... maybe you just have a lot of unfermentables.

That's exactly what I was thinking. 1.084 OG at 159* is going to leave a higher FG. I would have mashed that around 150* just for the sake of attenuation. The fact that you fermented warm should actually work in your favor, unless you're talking triple digit temps. You might try adding a huge starter with yeast nutrient and energizer of WLP099 or something like it.

 

[peterj]

I don't think you're going to get the FG any lower than that. As others have said 159F is a REALLY high mash temp so you probably just have a lot of unfermentable sugars. Does the article say to mash at 159? Seems like bad advice for such a high gravity beer. Especially if it's supposed to be an IIPA. I probably would have mashed at 149.

 

[mfranzer]

Thanks for all the replies so quickly!! It sure does say 159 in byo, but I have seem some posts in forums about this recipe and some have wondered if it was a misprint. I think I'll just take the 1.034 and be glad is isn't way higher!