Help me troubleshoot undershot gravity

So I just brewed Founder's Breakfast Stout clone (recipe from here, and posted below with my own slight adjustments).

Unfortunately, I was "tasting" some previously brewed beers with a friend throughout the brew day, and overlooked a few things in the process. My efficiency ended up around 55%. I should have went with a thinner mash and larger double sparge, but I just did my normal single batch sparge, cut it off at about 7 gallons preboil, threw it on the burner, got it down to 6.25 gal, then began my hop schedule. An hour later, somehow I end up with less than 5 gallons in the fermenter bucket, whereupon I said "screw it" and put in enough tap water to bring it up to around 5.3 gal. All in all, a very sloppy brew day.

So my problem, given my low efficiency, is that I undershot my gravity by at least 20 points. Recipe calls for 1.086, I measured appx 1.065 at pitching. What I'd like to do is bring up the gravity using a DME addition, but I want to make sure I add the right amount. (Assuming it will be okay for me to do so a day or two into fermentation.)

Here are my calculations:

1.086 OG x 5 gallon recipe = 430 GU
1.020 loss x 5 = 100 GU lost
100 GU / (45 GU/lb DME) = 2.22 lbs DME

Does this look right? Can I add 2.22 lbs of dissolved DME around high krausen and replicate 1.086 OG?





13 lb 2-Row
22 oz. flaked oats
1.0 lb. crisp chocolate malt (412 °L)
12 oz. Briess roast barley malt (300 °L)
9 oz. debittered, black malt (550 °L)
7 oz. crystal malt (120 °L)

2.0 oz. (57 g) ground Sumatran coffee
2.0 oz. (57 g) ground Sumatran coffee
2.0 oz. cocoa powder

1 oz Nugget pellet hops (60 min.)
1 oz Willamette pellet hops (30 min.)
1 oz Willamette pellet hops (5 min.)

4 oz (113 g) of corn sugar for priming

Mash at 155 for 60 min at 1.25 qt/lb
Add 2 oz coffee and cocoa at flameout, in bag

At bottling, dissolve 4 oz priming sugar in 2 oz coffee steeped in 1 qt of water in French press

Your math is spot on. I've been exactly were you are right now. You are going to need to dissolve it in water before adding it or it will take the yeast forever to work through the clumps. (don't ask me how I know). If you really want to be exact about it then the water you are disolving the 2.2 lbs of grain needs to be 1.086 wort. So if you use half a gallon of water that's an extra pound of DME. You might be able to get away with a quart of water and half a pound.

WoodlandBrew said:

Your math is spot on. I've been exactly were you are right now. You are going to need to dissolve it in water before adding it or it will take the yeast forever to work through the clumps. (don't ask me how I know). If you really want to be exact about it then the water you are disolving the 2.2 lbs of grain needs to be 1.086 wort. So if you use half a gallon of water that's an extra pound of DME. You might be able to get away with a quart of water and half a pound.

Click to expand...

So essentially you are saying create a 1.086 wort (with whatever amount of water and DME that requires) and then dissolve the 2.22 lbs DME into that?

Well... Pretty much. Sorry My post kind of rambled there.

2.2 lbs DME is what you need to get into your existing wort. To get that in there you need to dissolve it in water, but you don't want the water to water down the wort. There for the water needs to be replaced with a 1.086 wort. You could make a 1.086 wort and then use as much of that as needed to dissolve the 2.2lbs of DME, or you you do it all at once.

1.086 => 86 gravity points
86GP / 45 ppg = 1.9111 lbs/gallon
1.911 x 0.25 gallons = 0.478 lbs in one quart of water.
Or just call it half a pound.

Use 2.2+0.5 = 2.7 lbs of DME in 1 quart of water. If you can't dissolve everything add another quart of water and another half pound of DME.

WoodlandBrew said:

Well... Pretty much. Sorry My post kind of rambled there.

2.2 lbs DME is what you need to get into your existing wort. To get that in there you need to dissolve it in water, but you don't want the water to water down the wort. There for the water needs to be replaced with a 1.086 wort. You could make a 1.086 wort and then use as much of that as needed to dissolve the 2.2lbs of DME, or you you do it all at once.

1.086 => 86 gravity points
86GP / 45 ppg = 1.9111 lbs/gallon
1.911 x 0.25 gallons = 0.478 lbs in one quart of water.
Or just call it half a pound.

Use 2.2+0.5 = 2.7 lbs of DME in 1 quart of water. If you can't dissolve everything add another quart of water and another half pound of DME.

Click to expand...

Thank you!