OG Off - Insight Appreciated (Porter)

[natefrog255]

Today I brewed up a Porter (East River Scum) for the first time and my OG came in significantly lower than expected. I'll lay out the recipe and maybe you can offer advice, tips, etc.

East River Scum
6.6# of Pilsen LME (Briess)
0.5 oz. of Caramel 60
0.5 oz. of Chocolate
0.25 oz. of Black Malt
0.75 oz. Chinook Hops - 60 minutes
1 oz. Glacier Hops - 2 minutes


Crushed grain with rolling pins (don't have a mill) and steeped for 30 minutes in 2 gallons of water heated to 160 degrees. Once hit 160 turned off burner and steeped. After steep added just under 3 gallons of water and started boil.

Added 3.3# of LME near boil and 3.3# at the 50 minute mark.

OG wanted and expected was 1.049. After calibration ended up with only 1.041.

My personal feeling is either I'm not getting all of the LME out of the jugs and/or the grain isn't getting crushed properly but I don't know if it would have that drastic of an effect on the OG reading. Maybe my boil volume was too large. I normally shoot for 3 gallons but ended up with more.

Any info is appreciated!

 

[natefrog255]

I steeped the grains in 2 separate muslin bags. The Black/Chocolate were in one and the Caramel in the other.

 

[Calder]

East River Scum
6.6# of Pilsen LME (Briess)
0.5 oz. of Caramel 60
0.5 oz. of Chocolate
0.25 oz. of Black Malt
0.75 oz. Chinook Hops - 60 minutes
1 oz. Glacier Hops - 2 minutes

OG wanted and expected was 1.049. After calibration ended up with only 1.041.

I am going to assume the grain amounts are lbs, and not ounces. With steeping 1.25 lbs of mostly dark roasted grains, I would expect them to only contribute something like 15 to 18 points, or about .003 for a 5 gallon batch.

The LME will have about 240 points, or about .048 in 5 gallons.

So your expected OG was about right. Going from an expected 1.049 to 1.041 is about a 15% loss.

Since you did a full boil, I would have expected it to have mixed OK. Did you have more than 5 gallons in the fermenter? Did you leave much in the pot with the hops?

 

[natefrog255]

Yes, pounds not ounces for grain, oops.

I did go a little over the 5 gallon mark in the fermenter. I didn't think I did by much though. And I did leave a little in the kettle with the hop sediment, probably enough to cover the bottom. I guess that additional water minus a portion of the wort could've been the difference.

 

[abt]

This doesn't sound like a full boil. You're in a 5g kettle, right?
If you usually end up with 3g, say this time you had 3.5 maybe? Then those 240 points give you a 1.068 SG before draining the kettle.
If you left behind a quart, that's 5 points, now you have 235. You add an extra half gallon of top-up than normal, so now you are at 1.042 OG. I'm just making up quantities here, but you see how quickly a partial boil and slightly more finishing volume can drop points in the kettle loss.

 

[natefrog255]

This doesn't sound like a full boil. You're in a 5g kettle, right?
If you usually end up with 3g, say this time you had 3.5 maybe? Then those 240 points give you a 1.068 SG before draining the kettle.
If you left behind a quart, that's 5 points, now you have 235. You add an extra half gallon of top-up than normal, so now you are at 1.042 OG. I'm just making up quantities here, but you see how quickly a partial boil and slightly more finishing volume can drop points in the kettle loss.

My kettle is actually a 15g kettle, its the Penrose kettle from Brewhemoth. I started with 2 gallons while steeping grains. I added approx 3 gallons of water to that and began the boil. I ended up with a wort volume of about 4 gallons and topped off with water to a tad above 5 gallons. So what you said here makes sense and probably was the main reason of the lower OG. In the future I will make sure to drain all the wort and be more precise with my water volume for the boil.