how to calculate expected FG based on reading from beginning of boil? - Home Brew Forums

 Home Brew Forums > how to calculate expected FG based on reading from beginning of boil?

02-27-2013, 06:28 PM   #1
Eddiebosox
Recipes

Jan 2010
DC, Washington DC
Posts: 247
Liked 5 Times on 4 Posts

One of my problems has always been awful efficiency. Until I can work to fix it I was thinking of adjusting my mash by adding DME to compensate at the beginning of the boil to bring it up to the gravity it should be. Anyone know the math I should use to compensate based on a gallon per hour boiloff based on my original gravity readings before the boil?
__________________
Primary
Chocolate Hazelnut Imperial Porter

Kegged
House Bitter

02-27-2013, 06:34 PM   #2
hopmonster2189
Recipes

Mar 2012
Anacortes, Washington
Posts: 123
Liked 21 Times on 17 Posts

It's all in the free "how to brew" by Palmer online

02-27-2013, 06:45 PM   #3
peterj

Recipes

Sep 2012
Smyrna, GA
Posts: 1,638
Liked 309 Times on 210 Posts

C1*V1=C2*V2. C=concentration(gravity) V=volume. Drop the decimal if you're using SG (so 1.045 would be 1045). Or just use this calculator: http://www.brewersfriend.com/dilutio...ty-calculator/. I'm sure there's a bunch of other calculators online too.

02-27-2013, 07:56 PM   #4
dcp27
Recipes

Jan 2010
Medford, MA
Posts: 4,126
Liked 126 Times on 121 Posts

Quote:
 Originally Posted by peterj Drop the decimal if you're using SG (so 1.045 would be 1045).
you'd use 45, not 1045

02-27-2013, 08:16 PM   #5
peterj

Recipes

Sep 2012
Smyrna, GA
Posts: 1,638
Liked 309 Times on 210 Posts

Quote:
 Originally Posted by dcp27 you'd use 45, not 1045
Whoops, you're right. My mistake.

02-28-2013, 02:07 AM   #6
helibrewer

Recipes

Nov 2011
Santa Rosa, CA
Posts: 3,813
Liked 326 Times on 275 Posts

Quote:
 Originally Posted by Eddiebosox One of my problems has always been awful efficiency. Until I can work to fix it I was thinking of adjusting my mash by adding DME to compensate at the beginning of the boil to bring it up to the gravity it should be. Anyone know the math I should use to compensate based on a gallon per hour boiloff based on my original gravity readings before the boil?
I wouldn't add it at the beginning of the boil. Do your boil, take a gravity reading and see how many points you need. At this point you know your final volume and don't have to worry about boil off issues.

Add the appropriate amount of DME at flameout....dissolve well, take another gravity reading.

So lets say there are 6 gallons in the BK and the SG is 1.050.....but you want 1.060. So you need 10 more points. ppg = 10 points X 6 gallons = 60 ppg required. DME is 46 ppg so you would need 1.3 pounds (60/46) of DME to raise that 6 gallons to 1.060
__________________
Something is always fermenting....
"It's Bahl Hornin'"

Primary:
Kegged: Bourbon Barrel Imperial Stout
On Deck: German Lager

02-28-2013, 05:43 AM   #7
tgmartin000
Recipes

May 2011
Denver, CO
Posts: 1,276
Liked 95 Times on 77 Posts

Just use more grain if your eff is lower than expected.