Stuck Fermentation HELP!!!

[Crock_it_out]

I have a gingerbread stout sitting in the primary for going on almost 2-weeks. I pitched the WLP 011 pretty cold at like 62 and it was been fermenting at 64-66 degrees. I notice krausen has fallen and no airlock activity so I decided to take a measurement. OG 1.054(10/27) measure gravity today 1.032? Has a good gingerbread start but finished like a tree bark taste.

Recipe Specifications
--------------------------
Boil Size: 3.41 gal
Post Boil Volume: 3.12 gal
Batch Size (fermenter): 5.25 gal
Bottling Volume: 4.85 gal
Estimated OG: 1.052 SG
Estimated Color: 39.3 SRM
Estimated IBU: 31.5 IBUs
Brewhouse Efficiency: 72.00 %
Est Mash Efficiency: 0.0 %
Boil Time: 60 Minutes

Ingredients:
------------
Amt Name Type # %/IBU
12.0 oz Caramel/Crystal Malt - 80L (80.0 SRM) Grain 1 6.9 %
12.0 oz Chocolate Malt (Crisp) (415.0 SRM) Grain 2 6.9 %
8.0 oz Barley, Flaked (1.7 SRM) Grain 3 4.6 %
8.0 oz Carafoam (2.0 SRM) Grain 4 4.6 %
8.0 oz Oats, Flaked (1.0 SRM) Grain 5 4.6 %
4.0 oz Black (Patent) Malt (500.0 SRM) Grain 6 2.3 %
4.0 oz Roasted Barley (300.0 SRM) Grain 7 2.3 %
3 lbs DME Pilsen Light (Briess) (2.0 SRM) Dry Extract 8 27.8 %
3 lbs 4.8 oz LME Golden Light (Briess) (4.0 SRM) Extract 9 30.6 %
8.0 oz Brown Sugar, Dark (50.0 SRM) Sugar 10 4.6 %
8.0 oz Milk Sugar (Lactose) (0.0 SRM) Sugar 11 4.6 %
0.25 oz Galena [13.40 %] - Boil 60.0 min Hop 12 9.2 IBUs
2.00 oz Fuggles [5.30 %] - Boil 30.0 min Hop 13 22.3 IBUs
8.00 oz Malto-Dextrine (Boil 5.0 mins) Other 14 -
1.0 pkg European Ale (White Labs #WLP011) [35.49 Yeast 15 -

 

[shawnbou]

What was your expected FG?

Did you aerate before pitching? And did you make a starter?

With a pound combined of lactose and maltodextrin, plus over a pound of crystal malts (including the carafoam) that's a lot of unfermentable sugar, which would drive your FG up. But 1.054 to 1.032 still seems extremely low.

It's possible that you could be experiencing a perfect storm of three factors: 1) lots of unfermentables in the recipe, 2) the 1.020 extract bug, and 3) poor yeast performance. If so, rousing your yeast or raising the temperature may get you a few extra gravity points, or it may not. Knowing your expected FG will help diagnose the problem.

 

[Crock_it_out]

What was your expected FG?

Did you aerate before pitching? And did you make a starter?

With a pound combined of lactose and maltodextrin, plus over a pound of crystal malts (including the carafoam) that's a lot of unfermentable sugar, which would drive your FG up. But 1.054 to 1.032 still seems extremely low.

It's possible that you could be experiencing a perfect storm of three factors: 1) lots of unfermentables in the recipe, 2) the 1.020 extract bug, and 3) poor yeast performance. If so, rousing your yeast or raising the temperature may get you a few extra gravity points, or it may not. Knowing your expected FG will help diagnose the problem.

Beersmith has my expected FG at 1.012...but I know I need to accommodate for the lactose which Beeersmith doesn't. I didn't not pitch a starter...I usually do make one...but this time I just didn't. What is the 1.020 bug?

 

[TexanRudeboy]

Never heard of this extract bug. My last three batches got over 80% apparent attenuation. My BPA went down to 1.008 from 1.056. I make appropriate starters and have temp control though. Is it common?

 

[shawnbou]

The 1.020 "bug" is common with extract, though it's not like it happens to everyone every time. Do a search on this forum for 1.020 and you'll see what I mean. I've had lots of extract beers stall out around 1.020. I can't say with absolute certainty that's what's going on, but there's a very good chance.

IIRC it has to do with the fact that extract manufacturers have to make a "one size fits all" product so they mash in the middle, whereas PM and AG brewers can adjust mash temperatures depending on whether they want a drier or full-bodied beer.

According to this post and this post, lactose and maltodextrin have ppg of 35 and 40 respectively of unfermentable sugar, so adding a half pound of each to a 5 gallon batch is going to add 7.5 points of FG that BeerSmith doesn't account for.

That 7-8 points plus the 1.020 extract bug gets you to a potential FG of 1.028, not far from your current gravity.

I'd try rousing the yeast gently and raise the temperature to around 70-75°F. This late in fermentation, the higher temperature is not going to result in off flavors. If that doesn't change anything, though, I think this beer may be done. Have some friends over for a nice long session of dessert stout.

 

[ajf]

How did you measure the FG? Hydrometer or refractometer?

-a.

 

[Crock_it_out]

The 1.020 "bug" is common with extract, though it's not like it happens to everyone every time. Do a search on this forum for 1.020 and you'll see what I mean. I've had lots of extract beers stall out around 1.020. I can't say with absolute certainty that's what's going on, but there's a very good chance.

IIRC it has to do with the fact that extract manufacturers have to make a "one size fits all" product so they mash in the middle, whereas PM and AG brewers can adjust mash temperatures depending on whether they want a drier or full-bodied beer.

According to this post and this post, lactose and maltodextrin have ppg of 35 and 40 respectively of unfermentable sugar, so adding a half pound of each to a 5 gallon batch is going to add 7.5 points of FG that BeerSmith doesn't account for.

That 7-8 points plus the 1.020 extract bug gets you to a potential FG of 1.028, not far from your current gravity.

I'd try rousing the yeast gently and raise the temperature to around 70-75°F. This late in fermentation, the higher temperature is not going to result in off flavors. If that doesn't change anything, though, I think this beer may be done. Have some friends over for a nice long session of dessert stout.

Thanks a lot that really helps.....I swirled the better bottle around some although it didn't seem to disturb the trub that had already settled so I may need to swirl it some more..

 

[Crock_it_out]

How did you measure the FG? Hydrometer or refractometer?

-a.

Hydrometer

 

[shawnbou]

Thanks a lot that really helps.....I swirled the better bottle around some although it didn't seem to disturb the trub that had already settled so I may need to swirl it some more..

That's the idea. Swirl it just enough to kick up the trub but avoid splashing/foaming of the wort. Splashing may dissolve any air that's in the carboy headspace and lead to oxidation issues later on. Good luck!

 

[BeerMeDuffMan]

Really good info here, I was unaware of the 1.020 bug with extracts and couldn't for the life of me figure out why my quad was stuck at 1.021, even after adding temperature, champagne yeast, repitching, rousing. This would give a good explanation since I did use an extract recipe.

 

[TexanRudeboy]

Really good info here, I was unaware of the 1.020 bug with extracts and couldn't for the life of me figure out why my quad was stuck at 1.021, even after adding temperature, champagne yeast, repitching, rousing. This would give a good explanation since I did use an extract recipe.

I'd never heard of it either, but I've only got 4 extract batches under my belt. They've all been with Pilsen DME and steeping grains. That being such a light extract I can't imagine there's a ton of unfermentables in it. I guess that has something to do with not experiencing it.

Good to know if I run into it later.

 

[BeerMeDuffMan]

I'd never heard of it either, but I've only got 4 extract batches under my belt. They've all been with Pilsen DME and steeping grains. That being such a light extract I can't imagine there's a ton of unfermentables in it. I guess that has something to do with not experiencing it.

Good to know if I run into it later.

The only time I've had the issue was with pilsenet malt. I've done about 29 batches with extract and the quad was the only one I had the problem with. I wasn't paying attention to product specs and apparent attenuation

 

[duboman]

FYI, the lactose and malto dextrin can be added at packaging and then you don't have to worry about its effect on fermentation