two consecutive stuck ferms

i have been tring to replicate a red ale, but in two attemps so far i had a stuck ferm at 1.020, my target FG is 1.012.

nail al the steps to the dot, still dont now what is going wrong.

here is the recipe.

BeerSmith 2 Recipe Printout - http://www.beersmith.com
Recipe: American Red Ale
Brewer:
Asst Brewer:
Style: American Amber Ale
TYPE: All Grain
Taste: (30.0)

Recipe Specifications
--------------------------
Boil Size: 6.48 gal
Post Boil Volume: 5.98 gal
Batch Size (fermenter): 5.50 gal
Bottling Volume: 5.00 gal
Estimated OG: 1.051 SG
Estimated Color: 14.8 SRM
Estimated IBU: 29.1 IBUs
Brewhouse Efficiency: 72.00 %
Est Mash Efficiency: 75.3 %
Boil Time: 60 Minutes

Ingredients:
------------
Amt Name Type # %/IBU
10 lbs Munich Malt (9.0 SRM) Grain 1 93.0 %
8.0 oz Caramunich Malt (56.0 SRM) Grain 2 4.7 %
4.0 oz Special B Malt (180.0 SRM) Grain 3 2.3 %
0.70 oz Cascade [8.90 %] - Boil 60.0 min Hop 4 19.4 IBUs
0.50 oz Cascade [8.90 %] - Boil 15.0 min Hop 5 6.9 IBUs
0.50 oz Cascade [8.90 %] - Boil 5.0 min Hop 6 2.8 IBUs
1.0 pkg American Ale (Wyeast Labs #1056) [124.21 Yeast 7 -


Mash Schedule: Single Infusion, Medium Body, No Mash Out
Total Grain Weight: 10 lbs 12.0 oz
----------------------------
Name Description Step Temperat Step Time
Mash In Add 3.86 gal of water at 159.5 F 152.0 F 60 min

Sparge: Fly sparge with -7.59 gal water at 168.0 F
Notes:
------

all help is appreciated

cheers.

 

Are you using a refractometer to measure FG?

 

Thermometers calibrated?

 

What are your mash temps? The for sure way to hit 1.012 would be to lower them so you are getting more fermentable sugars. Do you make starters? I found they my FG went a bit lower after doing starters to pitch the right amount of cells.

 

i do use a refractometer, but since i have this problem i used the hidrometer just make sure i was getting the rigth reading, i used 2 termometers, 1 digital, 1 alcohol. my mash temp is 152, i yes im actually considering lower it to 148, can be a lack off oxigen???

 

Are you making a starter and aerating?

 

Munich malt has half the diastatic power of 2 row. It still self-converts, but not nearly as well, and it might take longer than some of your other brews. Did you test to see if you had any remaining starch? You might try a looser mash and give it an extra 15 minutes before you start fiddling with the temp.

Lack of oxygen certainly doesn't do yeast any favors, be we aren't talking about a high FG beer here. If you've brewed a bunch of other beers before and know how to aerate and pitch a proper amount of yeast, I wouldn't think that would be an issue for you.

 

Am I the only one who doesn't think that you're far enough off on FG to worry? How does it taste? I can understand wanting to improve your skills and get expected results, but being off by .08 could be any number of things. I wouldn't worry about it. I mean, if you're process is dialed in and you got 2 consecutive similar results...then you've succeeded. It could just be your brand of malts is different from what beersmith calculates.

 

you mean mash for a longer time, hour and a half??

 

no and no, but never have a n issue with onther brews, just this one.

cheers

 

"you mean mash for a longer time, hour and a half??"

Yes - buy some starch tester and start testing at 75,90 etc until you are sure you have full conversion. You're working with about half the converting power of a 2-row based recipe, so it could definitely take a bit longer than you are used to.

"Am I the only one who doesn't think that you're far enough off on FG to worry?"

Yes. The difference between 1.020 and 1.012 is pretty huge.

 

According to Mr Malty: http://www.mrmalty.com/calc/calc.html

You definitely under pitched by at least 50%. You would have needed two smack packs to reach the ideal pitching rate. I'm not saying it's why your fermentation is stuck, but generally you want to pitch a high number of healthy yeast to ensure a vigorous and complete fermentation.

 

60% attenuation is pretty low.

What strain of yeast are you using?
What does your fermentation temperature profile look like?
While I might not agree 100% with the need for a starter... aeration is fairly important in my mind (especially if you are not using a starter).

 

Make sure you take a reading of the final gravity with a hydrometer. The refractometer only works correctly, as is, with non-fermented wort (sugar water).

Check your hydrometer with 100% distilled water, should be 1.000 sg. If anything different you will have to add/subtract from your beer measurements by the same amount the water was off.


PS> there are formulas that can approximate FG from refractometer, but it's better to just use the hydrometer for this purpose. Refractometer is fantastic for everything pre-fermentation.

 

im using wyest 1056 american ale, i ferment @66 degress constant in a ferm chamber

 

which starch tester do you recomend??

 

Iodine