Stuck fermentation tip

[emichon]

Hi,

Just experienced my first stuck fermentation and looking for some additional tips on how I could restart the fermentation to at least bring down the gravity a bit more.

Unfortunately on brew day I was having some issues with my monster mill (which was my first time trying it), and I got increasingly frustrated so I didn't get the crush I wanted and I didn't get my expected efficiency. I was expecting 1. 069 ,but got 1.061, and because I was rushing I think I may have overshot my mash temp (I was aiming for 152f).

I made a starter so I would have had enough yeast pitched, and the fermentation started within a few hours and everything seemed to be going good, but after 24 hours everything seemed to have stopped. Gravity has stayed at 1.039 since. I tried a few tips I found online, but up to now nothing has worked, which is why I'm leaning towards that I overshot my mash temperature.

I tried increasing the temperature, swirled the wort, added some corn sugar (seemed to be a bit of activity after doing this) and pitched some additional yeast, and up to now nothing has worked. Is there any yeast than may be able to break down the more complex sugars assuming that is the issue?

Any advice would be appreciated

 

[Lefou]

No idea what yeast you used, but if you did overshoot your mash temps I'm not sure if a more attenuative yeast would help - and if it did, you may end up with more ABV than you planned on.
Fermentis has a dry Abbaye Ale yeast. I don't know if it's available for you or not, but that might be an approach to take. Another option would be to dilute the wort to the desired gravity, keg, and force carbonate.

 

[Lefou]

My hard, fast rules to avoid stuck fermentations:

Use a yeast with mid-high attenuation levels.
Keep wort gravity level to 1.050 or less.
Mash around 145F-155F, no higher until mashout.
Use amylase in the mash, and add a higher amount of Pilsner or malted wheat to increase enzymatic activity in your mash. Treating your mash water with CaCl2 helps.
Mash lower to increase fermentability for a faster fermentation and drier beer, if that's your preference. A dry beer is a preferable alternative to a stuck fermentation or pouring wort down the drain.
Worst case, you can use wort as a compost ingredient. It's acidic, roses like it, and can help your soil. I've done that, too. LOL

 

[IslandLizard]

How did you measure the gravity?

How long has it fermented?

 

[emichon]

This is the recipe if it helps. It was or 6.5 gallons but I only ended up with 6.

My yeast was about 45 days old, and I made a 1.75l starter (1.036 on a stir plate), so it should have been more than enough.

I measured my OG with both a hydrometer & a refractometer. For the gravity readings during fermentation, I initially took my readings with the refractometer, but after a few days I thought I may have been getting a false reading so I took a sample with the hydrometer, and it was the same.

When I pitched my yeast the wort temperature was 65f, and the ambient temperature of the room is usually always around 68f (It's in a finished basement). It's been in the fermenter for 8 days now, but hasn't changed since 7 days ago (I took my first reading after 24 hours, because something seemed off)

6.00 lb ESB Pale Malt
2.00 lb Oats, Flaked
1.00 lb Amber Malt
1.00 lb Carafa Special III
1.00 lb Caramunich III
1.00 lb Crystal 150
1.00 lb Midnight Wheat Malt
1.00 lb Pale Chocolate Malt
1.00 lb Special B
1.00 lb Wheat, Flaked
0.50 lb Aromatic Malt
1.00 lb Milk Sugar (Lactose)
0.50 oz Chinook [9.40 %] - Boil 60.0 min Hop 14 12.2 IBUs
0.50 oz Summit [15.90 %] - Boil 60.0 min Hop 15 20.6 IBUs
0.50 oz Chinook [9.40 %] - Boil 30.0 min Hop 16 9.4 IBUs
0.50 oz Summit [15.90 %] - Boil 30.0 min Hop 17 15.9 IBUs
2.50 oz Cacao Nibs (Boil 10.0 mins)
1.0 pkg Whitbread Ale (Wyeast Labs #1099)

 

[IslandLizard]

Refractometer readings need to be corrected once alcohol is present (they read too high). There are online calculators out there to do that.
But if your hydrometer shows the same gravity as the refractometer (without correction), something is wrong.

From 1.061 to 1.039 in 1 day is pretty fast, so the yeast was definitely working well, and should have plowed through it effortlessly. Was there a sharp temp drop perhaps, some yeasts are very sensitive to that and stall out.

WY1099 is a low attenuator, so it will finish higher than most other yeasts, but it should do better than this, unless... your higher mash temp denatured a lot of the beta-amylase prematurely, so you ended up with a very dextrinous wort.

Looking closer at your grain bill... Whoa!
You have a boatload of unfermentables in there. 3# of dark roast, 3# of Caramel (Crystal) malts, 1# of Lactose. Also .5# of Aromatic, 1# of Amber, aside from 3# of flaked adjuncts but only 6# of base malt.

==> What was your plan with this recipe?

The grist may have been a little low on diastatic power with all those other malts and flaked adjuncts. Overshooting the mash temps wasn't helping their cause either. Together with the low attenuating yeast, your beer may be simply done!

==> Most importantly, how does it taste right now? Like a super Dark Milk Mild?

As @Lefou said, a good healthy pitch of Abbaye or some other voracious (Belgian) yeast may be able to bring it down a few points, but don't expect miracles with all those unfermentables.

 

[behindthetimes]

I don't think you have a stuck ferment, in fact your FG of 1039 is in the range of what I'd expect to see if I brewed that recipe. In particular, note that the lactose is going to add about 0.010 to the FG no matter what. So without that you're down to about 1030 which sounds about right to me looking at that recipe.

 

[Lefou]

heh
NOW I understand why.
Your grain bill is light on base malt and leans heavily toward darker grains.

 

[emichon]

Regarding the refractometer, I did forget to mention that I did use Beersmith to get the correct converted calculations.

No sharp drop in temperature as my whole house is usually always around 68f (including the basement). In the summer I usually can't get the temperatures lower than this.

What I do find odd is that I did make this recipe last year and I went from 1.068 to 1.022. This year I made a few changes to the recipe, and I actually have less of the dark malt, and the ratio of the base malts is higher this time around. Which is another reason why I was thinking I would at least be getting around the same fermentation of even a bit better.

It tastes exactly as I would expect it with how the fermentation went. Extremely sweet & feels thick (and obviously very dark). It's not disgusting, but not what I was going for. My aim was to get it around 1.025-1.030 at least, but I guess I may have to live with it this time.

Refractometer readings need to be corrected once alcohol is present (they read too high). There are online calculators out there to do that.
But if your hydrometer shows the same gravity as the refractometer (without correction), something is wrong.

From 1.061 to 1.039 in 1 day is pretty fast, so the yeast was definitely working well, and should have plowed through it effortlessly. Was there a sharp temp drop perhaps, some yeasts are very sensitive to that and stall out.

WY1099 is a low attenuator, so it will finish higher than most other yeasts, but it should do better than this, unless... your higher mash temp denatured a lot of the beta-amylase prematurely, so you ended up with a very dextrinous wort.

Looking closer at your grain bill... Whoa!
You have a boatload of unfermentables in there. 3# of dark roast, 3# of Caramel (Crystal) malts, 1# of Lactose. Also .5# of Aromatic, 1# of Amber, aside from 3# of flaked adjuncts but only 6# of base malt.

==> What was your plan with this recipe?

The grist may have been a little low on diastatic power with all those other malts and flaked adjuncts. Overshooting the mash temps wasn't helping their cause either. Together with the low attenuating yeast, your beer may be simply done!

==> Most importantly, how does it taste right now? Like a super Dark Milk Mild?

As @Lefou said, a good healthy pitch of Abbaye or some other ferocious (Belgian) yeast may be able to bring it down a few points, but don't expect miracles with all those unfermentables.