Brewing Classic Styles: Adjusting for IBUs

[jholen]

Greetings!

Just plugging in some recipes from Brewing Classic Styles (BCS) into BeerSmith and vacuum packaging my hops for each batch, and wondering how I need to adjust for proper IBUs considering the specified hops used in BCS differ from my new hop pellets from HopsDirect.com.

BCS specifies the following:

Ordinary Bitter (6 gallons - 70% efficiency I believe)

8 lbs English Pale Malt
.5 lbs Crystal 120
.25 lbs Special Roast

EKG 5% AA - 1.2oz @ 60 mins (24.6)
EKG 5% AA - 0.5oz @ 30 mins (5.2)
EKG 5% AA - 0.5oz @ 1 min (1.7)

My hop pellets are the 2011 crop, and have a specified alpha acid of 4.4% - should I just adjust the amounts of hops until I match the specified IBU?

I should note, that I did change BeerSmith to use the Rager formula for calculating IBUs - I believe that is what Jamil uses

EKG 4.4% AA - 1.6oz @ 60 mins (24.7)
EKG 4.4% AA - 0.65oz @ 30 mins (5.1)
EKG 4.4% AA - 0.65oz @ 1 min (1.7)

Look right? Anything else to take into consideration when trying to use these BCS recipes? I know they are 6 gallon batches - meaning that 6 gallons of wort are left in the boil kettle after all is said and done, and that 5.5 gallons is transferred into the fermenter, resulting in 5 gallons after fermentation.

Considering I'm using Better Bottles, and they have a bit reduced capacity, would you suggest that I scale the recipe down a bit? Or just go with the recommended 5.5 gallons into the BB.

Thanks!

 

[wolfman_48442]

I adjust my hops inventory to match the numbers for the hops I currently have, then like you said, adjust amounts in the recipe to get correct IBU's per addition and total.

Maybe there's a more efficient way, but it seems to work good for me.

 

[samc]

The math:

5 x 1.2oz = 6

6 / 4.4 = 1.36 oz

 

[jholen]

Ugh.. now I realized that BeerSmith uses the pre-boil volume to calculate IBUs.

I'm a bit confused now - again, trying to match the recipes in BCS but my estimated pre-boil volume in BeerSmith for this 6 gallon batch size is now 9 gallons! When BCS calls for 7 gallons pre-boil, with 6 gallons left over.

This newb to AG/BCS/BeerSmith is confused.

 

[jholen]

So I've been doing more reading now.. and think I've got it figured out. I'm doing BIAB and have used the calculator from BIABrewer.info for calculating my volumes of water based on their recommendations as well as my equipment.

Here is what I've got figured for BeerSmith:

So.. IBUs seem to match up with what BCS calls for (32) as well as OG, and ABV. So in theory I should end up with 6 gallons left over in my boil kettle, and then can simply transfer 5 gallons into my Better Bottle and be good to go.