Kegconnection Complete Starter Kit and More Giveaway!


Home Brew Forums > Home Brewing Beer > Fermentation & Yeast > Flaked grains cause high final gravity and/or stuck fermentation?

Reply
 
LinkBack Thread Tools
Old 01-19-2011, 12:26 PM   #1
jclimacus
Feedback Score: 0 reviews
Recipes 
 
Join Date: Jan 2011
Location: Brooklyn, NY
Posts: 7
Default Flaked grains cause high final gravity and/or stuck fermentation?

Hi All.

Eight days ago I brewed a PM Tripel, using .5 lbs each of flaked oats, wheat and rye (1.5 total) along with 3 lbs of base malt. At the end of the mash (70 min @ 151) it was quite cloudy, and not as sweet as I remember previous ones being. I continued with the boil anyways, and was surprised to find that I had more or less hit my target gravity of 1.080. After some research, the cloudiness seems to have been due to unconverted starches from the flaked grains, as I did no protein rest.

Did those unconverted starches affect gravity in a significant way? For the last few days fermentation seems to have stalled (or finished?) around 1.022. I'm using Wyeast 3522 and I'd like to end up closer to 1.014 or drier, especially since the flaked grains have added a lot of body. Fermentation temps started at 67 and are up to 75.

The beer tastes very good, if a little too sweet, so I'm thinking there's something left for the yeast to eat. But could the gravity reading at this point be on account of starch?

__________________
jclimacus is offline
 
Reply With Quote Quick reply to this message
Old 01-19-2011, 04:06 PM   #2
pericles
Feedback Score: 0 reviews
Recipes 
 
Join Date: Dec 2007
Location: Bryn Mawr, PA
Posts: 744
Liked 20 Times on 20 Posts
Likes Given: 1

Default

Unconverted starches would be my bet for the cloudiness too. Without knowing exactly what grains you used, I can't say if I agree that the solution would have been to use a protein rest, or to use a cereal mash.

In other case, unconverted starches are not fermentable, so if that's your problem, then the yeast will not consume the remaining "sweetness." You might, however, be able to find an enzyme that will break down the starches and allow fermentation to complete? White Labs makes one called Ultra Ferm that would probably help.

__________________
Primary 1: Hasty IPA
Primary 2:
Secondary: Soured Golden
Kegged: American Wheat
Bottled: Belgian Golden Ale.
Planning: American Amber
pericles is offline
 
Reply With Quote Quick reply to this message
Old 01-19-2011, 05:33 PM   #3
jclimacus
Feedback Score: 0 reviews
Recipes 
 
Join Date: Jan 2011
Location: Brooklyn, NY
Posts: 7
Default

Thanks for the note. I basically followed Northern Brewer's grain bill:
1.5 lbs belgian pils
.75 oat malt
.75 pale wheat
.5 each: flaked barley, flaked oats, flaked wheat
2 lbs corn sugar
5 lbs extra light dme

So unconverted starches also impart sweetness to the beer, meaning any further attenuation won't eliminate them? Do they then contribute to the gravity as well?

__________________
jclimacus is offline
 
Reply With Quote Quick reply to this message
Old 01-19-2011, 05:41 PM   #4
pericles
Feedback Score: 0 reviews
Recipes 
 
Join Date: Dec 2007
Location: Bryn Mawr, PA
Posts: 744
Liked 20 Times on 20 Posts
Likes Given: 1

Default

To answer all three of your questions:

(1) I think that unconverted starches add more of a breadyness than a true sweetness. . . but yes, that might be what you're tasting, especially if they were partially converted.

(2) Yes, unconverted starches are not fermentable by standard brewing yeast, so no matter how long you wait, they will never be eliminated. If your gravity eventually falls because of rousing the yeast, raising the temperature, or just more time, then it wasn't unconverted starches to begin with.

(3) Yes, they contribute to the gravity. EVERYTHING you put in your beer contributes to the gravity, regardless of whether it's fermentable or not. Here's an example: when you swim in the ocean, you float higher than in a freshwater pool. When you swim in the dead sea (which is REALLY salty) you float even higher than in the ocean. That's true because YOU operate just like a hydrometer. Saying you "float higher" is the same as saying that the gravity of the dead sea is higher than the gravity of freshwater. Or, put yet another way, salt - which is clearly not fermentable - will add to the gravity of your beer.

So, long story short, unconverted starches, like salt, silica gel, and anything else that dissolves in water, will increase your gravity.

__________________
Primary 1: Hasty IPA
Primary 2:
Secondary: Soured Golden
Kegged: American Wheat
Bottled: Belgian Golden Ale.
Planning: American Amber
pericles is offline
 
Reply With Quote Quick reply to this message
Old 01-19-2011, 06:11 PM   #5
Teacher
Feedback Score: 0 reviews
Recipes 
 
Join Date: Sep 2007
Location: Grand Forks, ND, USA
Posts: 542
Liked 7 Times on 7 Posts
Likes Given: 2

Default

Did you cook the flaked grains first? This is what's needed before the mash temp. Protein rest doesn't convert starches (at least not significantly).

__________________
Teacher is offline
 
Reply With Quote Quick reply to this message
Old 01-19-2011, 06:19 PM   #6
bja
Feedback Score: 0 reviews
Recipes 
 
Join Date: Nov 2007
Location: Pittsburgh
Posts: 1,756
Liked 90 Times on 72 Posts

Default

Flaked adjuncts do not need to be cooked first.

__________________

____________________________________________

I know it just wouldn't be right to kill all the stupid people that we meet, but do you think it would be appropriate to just remove all of the warning labels and let nature take its course?

Life is tough. It's tougher if you're stupid.

bja is offline
 
Reply With Quote Quick reply to this message
Old 01-19-2011, 06:28 PM   #7
jclimacus
Feedback Score: 0 reviews
Recipes 
 
Join Date: Jan 2011
Location: Brooklyn, NY
Posts: 7
Default

I did not cook them before mashing.

I'm gradually raising the temp up to about 80. Maybe it is a sign that the yeast is still active in that the krauesen shows no sign of wanting to fall. Perhaps I'm just being impatient, but in the past all my beers of similar, and greater, size have attenuated within a week.

__________________
jclimacus is offline
 
Reply With Quote Quick reply to this message
Old 01-19-2011, 06:45 PM   #8
TheBeerist
HBT_SUPPORTER.png
Feedback Score: 0 reviews
 
TheBeerist's Avatar
Recipes 
 
Join Date: Nov 2010
Location: Santa Ana, CA
Posts: 250
Liked 11 Times on 11 Posts
Likes Given: 4

Default

Quote:
Originally Posted by bja View Post
Flaked adjuncts do not need to be cooked first.
Flaked oats do.
__________________
TheBeerist is offline
 
Reply With Quote Quick reply to this message
Old 01-19-2011, 06:47 PM   #9
bja
Feedback Score: 0 reviews
Recipes 
 
Join Date: Nov 2007
Location: Pittsburgh
Posts: 1,756
Liked 90 Times on 72 Posts

Default

Quote:
Originally Posted by TheBeerist View Post
Flaked oats do.
No they don't. That's already been done.
__________________

____________________________________________

I know it just wouldn't be right to kill all the stupid people that we meet, but do you think it would be appropriate to just remove all of the warning labels and let nature take its course?

Life is tough. It's tougher if you're stupid.

bja is offline
 
Reply With Quote Quick reply to this message
Old 01-22-2011, 12:35 AM   #10
TheBeerist
HBT_SUPPORTER.png
Feedback Score: 0 reviews
 
TheBeerist's Avatar
Recipes 
 
Join Date: Nov 2010
Location: Santa Ana, CA
Posts: 250
Liked 11 Times on 11 Posts
Likes Given: 4

Default

Quote:
Originally Posted by bja View Post
No they don't. That's already been done.
I may not have been clear, and I apologize. Quick oats, are partially gelatinized but they will still benefit from being cooked before hand, although it is not absolutely necessary. Flaked oats are those garbage instant oats at the grocery store, and I wouldn't eat them, much less put them in by beer.

Old Fashioned oats have not been pre-gelatinized and need to be cooked first as their gelatinization temperature is far below a typical mash temperature. I eat these for breakfast so this is what I use, and this is what my friends use as well. We make some pretty killer stouts if I don't say so myself.

Edit To the OP: what kind of oats did you use? Proper quick oats from the LHBS, or the Quaker Oat variety? If you went with the Quaker Oats, were they quick oats? Or old fashioned?
__________________

Last edited by TheBeerist; 01-22-2011 at 12:38 AM.
TheBeerist is offline
 
Reply With Quote Quick reply to this message
Reply


Quick Reply
Message:
Options
Thread Tools


Similar Threads
Thread Thread Starter Forum Replies Last Post
Is this final gravity too high? austinb Fermentation & Yeast 3 12-11-2013 03:16 AM
High Final Gravity Issues... SkyHighBrew88 Fermentation & Yeast 9 08-05-2010 09:58 PM
high final gravity DeepSea Fermentation & Yeast 8 04-25-2010 09:12 PM
High Gravity Fermentation bootney Fermentation & Yeast 21 04-21-2010 12:44 AM
Final Gravity too high. What to do? eurc51 Fermentation & Yeast 7 04-14-2010 11:26 PM