OG was way off not sure why?

[powerpunk5000]

I did my brew today, here is the grain bill

BIAB

2.5 Gallon in the fermenter

3 gallon mash 155

1 gallon sparge 170

5.5 lbs Briess - Brewers Malt 2-Row (1.8 °L)


.25 lbs American - Caramel / Crystal 120L (120 °L)


.25 lbs American - Chocolate (350 °L)


.75 lbs Briess - Brewers Oat Flakes (2.5 °L)


1.5 OZ Flaked Barley (2.2 °L)


Total: 7.17 lb

expected OG 1.073


my actual gravity came out to about 1.048-1.50 Which is way off

I had all my grains crushed at the local HB store

heated up my strike water to 170

placed my grains in a bag and and into the water

the whole pot was then placed in the oven at 170 for one hour.

it was stired twice and the temp seemed to be around 150-155

any ideas why it was so low?

 

[powerpunk5000]

also the color is like a brown vs a jet black like a stout should be :/

 

[powerpunk5000]

I was expecting my BIAB to have about 75% efficiency and got about 50%

 

[RM-MN]

I had all my grains crushed at the local HB store

Clue number one. The quality of the the crush is the biggest factor in efficiency. If you want to be able to hit your expected numbers the first thing is to control the crush by using your own mill.

heated up my strike water to 170

Clue number 2. When I BIAB my strike temp is near 160, not 170. That may not be a problem but 170 degree water will denature a lot of the enzymes. If you stirred the grains in quickly so the temperature came down to 150-155 right away this shouldn't be the problem.

 

[McKnuckle]

Your grains add up to 6.84 lbs, not 7.17 lbs. Not a huge difference but makes the rest of your math worth double checking.

Read the tons of threads on this subject - grain crush is the absolute #1 reason for poor efficiency, whether BIAB or otherwise.

How much wort volume at the start of the boil, and how much at the end?

Only 7.3% of your grain bill is dark roasted (I’m including the crystal even though perhaps I shouldn’t), and even 350L chocolate malt is not that dark to produce a stout of the expected color. You need a decent contribution from roasted barley, black malt, or Carafa III in a stout (500L).

Did you put this recipe together using software so you could predict the resulting beer’s attributes?

 

[powerpunk5000]

Your grains add up to 6.84 lbs, not 7.17 lbs. Not a huge difference but makes the rest of your math worth double checking.

Read the tons of threads on this subject - grain crush is the absolute #1 reason for poor efficiency, whether BIAB or otherwise.

How much wort volume at the start of the boil, and how much at the end?

Only 7.3% of your grain bill is dark roasted (I’m including the crystal even though perhaps I shouldn’t), and even 350L chocolate malt is not that dark to produce a stout of the expected color. You need a decent contribution from roasted barley, black malt, or Carafa III in a stout (500L).

Did you put this recipe together using software so you could predict the resulting beer’s attributes?

yes i used brewers friend to come up with everything, I guess I jut expected the local Homebrew store to crush the grains properly

 

[LittleRiver]

... I jut expected the local Homebrew store to crush the grains properly

If they crush grains fine enough for BIAB, that will cause problems for people who don't BIAB (traditional mash tuns, etc). The relatively coarse setting of most homebrew store mills is a reasonable thing.

If you're going to BIAB, and you want high efficiency, you need your own grain mill.

 

[McKnuckle]

I put your grain bill into my own spreadsheet, including the 3 gallons of mash liquor and 1 gallon sparge.

First, the color is 21.4 SRM, which is brown ale territory.

Most importantly, though, it takes 100% conversion efficiency to hit 1.073 OG. On my setup, that means 92.2% mash efficiency. Clearly those are not numbers that I would hit, either. So your expectations were off from the start.

To hit 1.049 OG, I'm seeing 65% conversion and 60% mash efficiency. Those are poor numbers, so I'm guessing the causes are, in this order:

1) Crush
2) Strike temp too hot
3) Mash pH (don't worry about this one yet)

 

[Steveruch]

When I was doing all grain I did three gallon batches and with 7.8 lbs of store crushed grain would have expected an O G in the low 1.050s.