Brewer's Friend Beer Recipe Calculator

Hey all-

Can anyone advise as to why that when I take a recipe I find on here and put it into the Brewer's Friend Beer Recipe Calculator, it doesn't match in regards to SG, FG, IBU's, SRM, etc.?

Example, I take a 5 gallon recipe for a Stout, scale it down to my 1-gallon batches, then plug everything in. My numbers don't match the original recipe's numbers...Why?

Hi, This is Larry from Brewer's Friend. Try entering it at 5 gallons (or whatever it is provided at), and then use the Scale feature provided by the recipe editor. The numbers should line up pretty close. If not, look for differences in hop AA values or grain ppg/lovibond values. Yeast attenuation can also impact FG, and there is an option for custom attenuation. You can also click the 'More...' button and choose different equations, that could also be contributing to the differences. Simple huh?!

There is a lot of variation out there, but we can get to the bottom of it. Please provide some sample recipes. It should not be too hard to narrow it down.

PROST!

larrybrewer said:

Hi, This is Larry from Brewer's Friend. Try entering it at 5 gallons (or whatever it is provided at), and then use the Scale feature provided by the recipe editor. The numbers should line up pretty close. If not, look for differences in hop AA values or grain ppg/lovibond values. Yeast attenuation can also impact FG, and there is an option for custom attenuation. You can also click the 'More...' button and choose different equations, that could also be contributing to the differences. Simple huh?!

There is a lot of variation out there, but we can get to the bottom of it. Please provide some sample recipes. It should not be too hard to narrow it down.

PROST!

Click to expand...

Larry,

I recently put in two variations of EdWort's Haus Pale Ale into the calculator, one for extract and one for AG, and got signifigant differences (extract was about half of the AG recipie) between the two for the IBUs. Same hops for both recipes.

AG - 40.67 IBU
8# Pale 2 Rox
2# Vienna
.5# Crystal 10L

1 oz Cascade @ 60 min
.5 oz Cascade @ 30 min
.25 oz Cascade @ 15 min
.25 oz Cascade @ 5 min

Nottingham yeast

Extract - 23.67 IBU
6.5# Extra Light LME
1.5# Munich LME
.5# Crystal 10L

same hops, same yeast.

OG, FG, ABV and SRM are all pretty close for the two variations, only the IBUs differ significantly.

Any idea why the difference? Is it just the nature of extract vs AG?

It is probably because of the boil volume. The IBU Tinseth equation considers the gravity of the boil, where the IBU Rager equation does not. Since an extract batch is usually a 2.5 gallon boil, and an all grain batch is a full boil (~7 gallons) that makes a big difference in hops utilization. My guess is the Rager equation will be closer between the two batches.

Glad you are enjoying the site! Keep the questions coming. You can also reach us through the contact page at the site.

Another thing you can do to lower the boil gravity is to split the extract into two lines and mark the second line as a 'late addition'. The gravity contribution from the late addition is not factored into the boil gravity, thus the IBUs will go up.

So if you had 6 pounds of DME, set it up with two lines of DME, 3 pounds each, then mark the second line as a late addition (that option becomes visible by clicking the down arrow for that row).