Perplexing Pale Ale

**ChemE** · 05-30-2009, 12:06 AM

Oddly enough this was to be the name of this recipe anyway but it turned out to live up to its moniker. I'm hoping some of the oddity can be explained by others with more experience. First the recipe...

Code:

Section 2: Recipe Information
Name of Brew: Perplexed Pale Ale
Entry Category: American Pale Ale 	Type: All Grain
Category Number: 10 	Subcategory Letter: A
Starting Gravity: 1.057 SG 	Batch Size: 5.50 gal
Final Gravity: 1.026 SG 	Mash Profile: Single Infusion, Light Body
  	 

Hops Used

Amount 	Item 	Type 	% or IBU
1.00 oz 	Cascade [7.20 %] (Dry Hop 14 days) 	Hops 	-
1.00 oz 	Centennial [9.00 %] (Dry Hop 14 days) 	Hops 	-
0.25 oz 	Cascade [7.20 %] (75 min) (First Wort Hop) 	Hops 	6.1 IBU
0.25 oz 	Centennial [9.00 %] (75 min) (First Wort Hop) 	Hops 	7.6 IBU
0.50 oz 	Centennial [9.00 %] (20 min) 	Hops 	8.1 IBU
0.50 oz 	Cascade [7.20 %] (20 min) 	Hops 	6.4 IBU
 

Grains Used

Amount 	Item 	Type 	% or IBU
6 lbs 12.0 oz 	Pale Malt, Maris Otter (3.0 SRM) 	Grain 	67.50 %
1 lbs 2.0 oz 	Caramel/Crystal Malt - 40L (40.0 SRM) 	Grain 	11.25 %
1 lbs 	Barley, Flaked (1.7 SRM) 	Grain 	10.00 %
10.0 oz 	Caramel/Crystal Malt - 10L (10.0 SRM) 	Grain 	6.25 %
4.0 oz 	Aromatic Malt (26.0 SRM) 	Grain 	2.50 %
4.0 oz 	Biscuit Malt (19.3 SRM) 	Grain 	2.50 %
 

Other Ingredients Used

Amount 	Item 	Type 	% or IBU
2.00 gm 	Epsom Salt (MgSO4) (Mash 60.0 min) 	Misc 	
3.00 gm 	Calcium Chloride (Mash 60.0 min) 	Misc 	
12.00 gm 	Gypsum (Calcium Sulfate) (Mash 60.0 min) 	Misc 	
 

Yeast Used

Amount 	Item 	Type 	% or IBU
1 Pkgs 	Nottingham (Danstar #-) 	Yeast-Ale

Now, the oddity started when there was no airlock activity or krausen formation 72 hours after pitching. I was out of town and so wasn't able to confirm a lack of activity with a hydrometer reading so I asked my wife to pitch some S-04 that I had in the fridge. It was either risk overpitching or risk infection; seems like an easy choice to me. That got fermentation started and 3 days later (when I got home) it had stopped at 1.026. I gently shook the fermenter but a week later the gravity was still 1.026.

Okay so let's rule out easy culprits...

Mash temp: my thermometers (I use two) were both two-point calibrated about a month ago and they both read the mash temp as 153 (dropped to 151 after 60 minutes).

Aeration: I shook the carboy for 5 minutes AND aerated with a 2.0 mm SS stone, HEPA filter, and aquarium pump. I very very seriously doubt the yeast stopped from lack of oxygen.

Yeast age: although old (20 months, damn LHBS) both packages of yeast were within their 2-year shelf life

Fermentation temperature: this is my best guess, I was too lazy to grab a suitable water/ice bath container prior to pitching so the carboy was in a 74F house. I didn't have a carboy thermometer at the time and wasn't in town for initial fermentation anyway so I've no clue how hot the carboy got.

So any ideas on why the beer stopped at 1.026? Could it be the protein from the pound of flaked barley? Seems unlikely to me. Any other ideas?

**big supper** · 05-30-2009, 12:18 AM

you have a lot of crystal/caramel malts that will provide unfermenables. Not the only reason....but could be part of it.

**ajf** · 05-30-2009, 01:26 AM

I read the other day (I can't remember where - but it was from a trustworthy source) that British Pale Malts like Maris Otter only have enough enzymes to convert themselves.
I've used Maris Otter to convert up to 10% flaked barley without problems, but you were using over 16%

-a.

**ChemE** · 05-30-2009, 02:09 AM

No, 16% crystal but only 10% flaked barley. I was always under the impression that MO has very high diastatic power though; well over 120 lintner.

pericles · 05-30-2009, 06:56 PM

Something worth keeping in mind is that you don't know how the yeast got to your LHBS. If it was shipped there, it could have been exposed to any number of extreme conditions. That, coupled with 20 months on ice, makes it an iffy proposition to use.

-Jack

**ajf** · 05-30-2009, 09:44 PM

My %age was based on the amount of flaked barley (which requires conversion) to the amount of M.O. (which has to provide the enzymes for conversion). The other malts don't help in the conversion, and don't require mashing.

American 2 row has high diastatic power. English is much lower

"Starch conversion: Diastatic power (°Lintner, IOB). Diastatic power (DP) expresses the strength of starch-reducing enzymes in the malt and is measured in °Lintner (sometimes referred to as IOB or .25 maltose equivalent). Diastatic power, considered together with mealiness/vitreosity (see below), indicates how well a malt will respond to mashing. The DP may be as low as 35-40 for a well-converted, low-protein British ale malt, about 100 for a European lager malt, and 125 or greater for high-protein American two-row malt. Six-row malts can have DPs as high as 160. The latter malts have more protein, and thus more enzymes to reduce far more than just their own starches, while the British malts have enough only to convert their own weight under normal infusion mash conditions."

From BMG - Understanding Malt Analysis Sheets -- How to Become Fluent in Malt Analysis Interpretation

-a.

**ChemE** · 05-30-2009, 10:56 PM

pericles - I agree; I would have preferred to use a liquid starter but you're right that could easily have contributed to or caused the poor attenuation.

Good point ajf. I use Munton's MO and they suck at publishing typical malt analysis. The best I've found is this Muntons | World Class Malt | Home and it still isn't clear if this is their Marris Otter of a different malt.

Oddly enough now that I added the 2 oz of dry hops the airlock has started back up and there is a few slight foam at the top surface of the beer against the carboy. Not sure if the CO2 is just nucleating on the hops and bubbling out or if the hops introduced something which is further fermenting the beer. I'll check it again Monday when I go to bottle it just out of idle curiosity though.

**ChemE** · 05-31-2009, 03:33 AM

Couldn't resist taking a gravity reading this evening. Down to 1.024 so something restarted fermentation. My guess is something which rode in on the dry hops since I'd already agitated the fermenter and that didn't restart fermentation.

**passedpawn** · 06-01-2009, 02:53 AM

If you get desperate, add some beano. I have never done so, but if I ever get in a bind and think that fermentation is stuck, I'll try it.

althalos · 06-01-2009, 02:47 PM

I had this problem when my wort was warmer than the surrounding air and sucked the sanitizing fluid from my airlock into the fermenter. I have a waterless airlock now and I love it.

Other than that, can't say anything else that isn't already on here.