agusus
Well-Known Member
How is this even possible? Just finished a 4 hour brew session and took my gravity, and I'm stunned. I totally expected bad efficiency on my first partial mash using the brew in the bag technique -- but not this bad. I was hoping for 70% efficiency, but according to BeerSmith I got 35% efficiency!
As far as I know, I did everything right for the process. I've done 8 extract batches so I don't think this was an issue with measuring the gravity wrong. I took the gravity after adding my top off water to get to 5.1 gallons and thoroughly mixing the wort by rolling and shaking the carboy. It was at 75 F.
So my imperial stout which was supposed to be 8.3% ABV, OG 1.085 is now going to be a normal stout at 6%, OG 1.064 (but at 50 IBUs it'll probably be rather bitter for that malt profile).
Here are the numbers:
Target OG: 1.085
Actual OG: 1.064
Mashed 8.5 lb of grains at 152 F for 70 minutes in 3.25 gallons of water (water to grain ratio of about 1.5 qt/lb). I covered the pot during the 70 minutes, and the temp held well - at 60 minutes it was only down to 149. I didn't do a mash out or sparge. I checked temp and stirred the grains every 15 minutes to make sure they weren't clumping (as far as I could tell, they weren't). I let the bag drain over the pot until the output slowed after about 5 minutes, and then I bounced and squeezed it a little. It yielded ~2.6 gallons of wort (from the 3.25g strike water).
The grains were:
7 lb US 2-row
0.94 lb chocolate malt
0.44 lb roasted barley
0.19 lb black patent
Then I had 6 lbs of pilsner liquid extract. BeerSmith says that 6 lb extract alone would give an OG of 1.043, so basically my 8 lbs of grain only gave me 21 gravity points. That's about 2.9 lbs of extract. There's no point in doing BIAB again if 8 lbs grain is only going to save me 2.9 lbs in extract.
From the dozens of webpages and forums I've read on BIAB, everyone has said they were getting in the 70-80% efficiency range and that a sparge isn't necessary. I know not doing a mash-out can cost 5% or so in efficiency, but that still should have put me at 65-70%, not 35%.
Any have any clue what could explain this?
As far as I know, I did everything right for the process. I've done 8 extract batches so I don't think this was an issue with measuring the gravity wrong. I took the gravity after adding my top off water to get to 5.1 gallons and thoroughly mixing the wort by rolling and shaking the carboy. It was at 75 F.
So my imperial stout which was supposed to be 8.3% ABV, OG 1.085 is now going to be a normal stout at 6%, OG 1.064 (but at 50 IBUs it'll probably be rather bitter for that malt profile).
Here are the numbers:
Target OG: 1.085
Actual OG: 1.064
Mashed 8.5 lb of grains at 152 F for 70 minutes in 3.25 gallons of water (water to grain ratio of about 1.5 qt/lb). I covered the pot during the 70 minutes, and the temp held well - at 60 minutes it was only down to 149. I didn't do a mash out or sparge. I checked temp and stirred the grains every 15 minutes to make sure they weren't clumping (as far as I could tell, they weren't). I let the bag drain over the pot until the output slowed after about 5 minutes, and then I bounced and squeezed it a little. It yielded ~2.6 gallons of wort (from the 3.25g strike water).
The grains were:
7 lb US 2-row
0.94 lb chocolate malt
0.44 lb roasted barley
0.19 lb black patent
Then I had 6 lbs of pilsner liquid extract. BeerSmith says that 6 lb extract alone would give an OG of 1.043, so basically my 8 lbs of grain only gave me 21 gravity points. That's about 2.9 lbs of extract. There's no point in doing BIAB again if 8 lbs grain is only going to save me 2.9 lbs in extract.
From the dozens of webpages and forums I've read on BIAB, everyone has said they were getting in the 70-80% efficiency range and that a sparge isn't necessary. I know not doing a mash-out can cost 5% or so in efficiency, but that still should have put me at 65-70%, not 35%.
Any have any clue what could explain this?