Stuck Oatmeal?

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Ilan34

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I brewed Yooper's Oatmeal Stout recipe 12 days ago. 2.5 gallon batch, mashed at 155, got an OG of 1.057. Aerated with oxygen for 35 seconds. Pitched a 1 liter decanted starter of WLP004 Irish Ale. Began ferment in chamber at 65 degrees.

Steady bubbling action within four hours. Within 36 hours the krausen had dropped and I ramped it up to 68 and then to 72 over the next 24 hours. It stayed at that temp until last night.

Took a gravity reading, came in at 1.026! I know it's early but that's only 54% attenuation. This is my third dark beer that's giving me readings in the mid to high 20's. I don't really understand why that is. I would have thought that with a starter, temp control, and oxygen, I'd be all good now.

So I sanitized my racking cane and gently swirled up the trub and then rolled the carboy a little. Stuck the temp probe back on and cranked it to 81. I'll leave it like that for now and take another reading Sunday or Monday.

Any thoughts on why this happens with my dark brews?

As an aside, the sample had a distinct sour note to it. Will this condition out or only get worse? I used EZ Water to make adjustments and while I don't have a pH meter yet, my mash pH should have been about 5.46.
 
Friday afternoon bump, looking to make it go just that much faster!
 
I would imagine since it is only dark beers that it might be a ph issue. How to fix it now is beyond my knowledge but I would steep your dark grains seperately next time and see if that helps. Wish I could help out more on this current batch.
 
kaconga said:
I would imagine since it is only dark beers that it might be a ph issue. How to fix it now is beyond my knowledge but I would steep your dark grains seperately next time and see if that helps. Wish I could help out more on this current batch.
Click to expand...

Thanks for the advice! So can pH cause sick fermentations? I wasn't aware of that. But I'm a real novice with water issues.
 
That would be "stuck" fermentations. Although sick kind of works too.
 
Ilan34 said:
Thanks for the advice! So can pH cause sick fermentations? I wasn't aware of that. But I'm a real novice with water issues.
Click to expand...

It is not technically stuck. Rather it was improperly mashed due to ph so you have too much dextrin malt and/or unconverted starch. If you did an iodine starch test and it came out good then it is dextrins (unfermentable sugars). If you want to know your limit of attenuation then just draw off a hydro sample and put it on your stirplate. Let that go for a few days at a warm temp and then take a reading. This reading is the lowest gravity this beer could ever go. Typically you only get to 85-90% of this limit.
 
kaconga said:
It is not technically stuck. Rather it was improperly mashed due to ph so you have too much dextrin malt and/or unconverted starch. If you did an iodine starch test and it came out good then it is dextrins (unfermentable sugars). If you want to know your limit of attenuation then just draw off a hydro sample and put it on your stirplate. Let that go for a few days at a warm temp and then take a reading. This reading is the lowest gravity this beer could ever go. Typically you only get to 85-90% of this limit.
Click to expand...

That's really interesting. I might just do that. So, are you saying EZ Water was wrong or are you saying that a pH of 5.46 is too low? According to Ward Labs, my water has a pH of 8.7. I even added 0.5 ml of lactic acid to try to bring the pH down...!
 
Ilan34 said:
That's really interesting. I might just do that. So, are you saying EZ Water was wrong or are you saying that a pH of 5.46 is too low? According to Ward Labs, my water has a pH of 8.7. I even added 0.5 ml of lactic acid to try to bring the pH down...!
Click to expand...

Calculated is a great starting place but measured is always better. I think if I was having this issue I would assume a bad measurement somewhere was throwing off my calculations. If you can hit your targets with lighter beer but not darker then I would either consider the steeping like I first said or buy a ph meter to get it dialed in. So basically I am saying the calculated ph is most likely wrong. The limit of attenuation test and iodine testing will help determine if it is a mashing issue or a fermentation issue.
 
Ilan34 said:
I brewed Yooper's Oatmeal Stout recipe 12 days ago. 2.5 gallon batch, mashed at 155, got an OG of 1.057. Aerated with oxygen for 35 seconds. Pitched a 1 liter decanted starter of WLP004 Irish Ale. Began ferment in chamber at 65 degrees.

Steady bubbling action within four hours. Within 36 hours the krausen had dropped and I ramped it up to 68 and then to 72 over the next 24 hours. It stayed at that temp until last night.

Took a gravity reading, came in at 1.026! I know it's early but that's only 54% attenuation. This is my third dark beer that's giving me readings in the mid to high 20's. I don't really understand why that is. I would have thought that with a starter, temp control, and oxygen, I'd be all good now.

So I sanitized my racking cane and gently swirled up the trub and then rolled the carboy a little. Stuck the temp probe back on and cranked it to 81. I'll leave it like that for now and take another reading Sunday or Monday.

Any thoughts on why this happens with my dark brews?

As an aside, the sample had a distinct sour note to it. Will this condition out or only get worse? I used EZ Water to make adjustments and while I don't have a pH meter yet, my mash pH should have been about 5.46.
Click to expand...

What's the recipe like so we can get a feeling for how much unfermentables could be in there. Oatmeal Stouts sometimes are brewed with lactose, did you use any of that? How much crystal did you use, as well as how much flaked oats? Is it possible you accidently went higher than 155 during the mash?
 
The following is Yooper's original recipe. I scaled down to 2.5 gallons.


7 lbs Pale Malt, Maris Otter (3.0 SRM) Grain 63.64 %
1 lbs Oats, Flaked (1.0 SRM) Grain 9.09 %
12.0 oz Victory Malt (25.0 SRM) Grain 6.82 %
10.0 oz Chocolate malt (pale) (200.0 SRM) Grain 5.68 %
8.0 oz Barley, Flaked (1.7 SRM) Grain 4.55 %
8.0 oz Black Barley (Stout) (500.0 SRM) Grain 4.55 %
8.0 oz Caramel/Crystal Malt - 80L (80.0 SRM) Grain 4.55 %
2.0 oz Chocolate Malt (450.0 SRM) Grain 1.14 %

2.00 oz Williamette [4.80 %] (60 min) Hops 31.6 IBU.
 
Should be okay, but a pound of oatmeal at 2.5 gallons is a good bit. The style itself leaves a bit higher FG... but it should be able to get a bit lower i'd like to think. I've had some end that high that have still turned out great, but I used Lactose. If rousting the yeast by stirring/shaking it to get them back into suspension doesn't do it, you could get more yeast and make a starter and pitch that to see if it helps.
 
Sorry, I should have been clearer. I posted Yooper's actual recipe, but not my scaled amounts. I only used 8 ounces of flaked oatmeal.
 

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