WTK: Proper IBU Range for Imperial Porter

I plan on brewing an imperial porter (derived from an incomplete recipe) with a starting gravity of 1.086 to 1.088 that should terminate around 1.016 to 1.018 for an ABV of 9%.

The recipe calls for Phoenix @ 90 minutes and First Gold @ 30 minutes.

What I don’t know is the IBU target of the recipe.

So … with an imperial porter starting at 1.088, what should the IBU target be?

Since Imperial Porter isn’t a proper BJCP style, the interpretation is pretty much left up to you. I’m assuming that this is a scaled-up Robust Porter recipe? My WAG is somewhere in the range of a 0.5 BU:GU ratio. So, maybe in the 40-50 IBU range. You could probably go as high as 60-70 if you want more bite or as low as 20-30 if you want less bitterness.

How long is a piece of string?  It all depends on what kind if flavor profile you’re looking for.  I’ll start by saying that your idea of FG is lower than what I shoot for on a similar beer.  As an example, take a look at my recipe below.  It finishes about 1.026ish.  A lower FG will enhance the perception if dryness and might require a lower hopping rate.  But first, let’s talk about how you think this beer should taste. Using your “taste imagination”, what are you shooting for?

#264 Bourbon Vanilla Imperial Porter

A ProMash Recipe Report

Recipe Specifics

Batch Size (Gal):        5.00    Wort Size (Gal):    5.00
Total Grain (Lbs):      17.75
Anticipated OG:          1.086    Plato:            20.58
Anticipated SRM:          45.4
Anticipated IBU:          31.8
Brewhouse Efficiency:      73 %
Wort Boil Time:            70    Minutes

Pre-Boil Amounts

Evaporation Rate:      1.50    Gallons Per Hour
Pre-Boil Wort Size:    6.75    Gal
Pre-Boil Gravity:      1.063    SG          15.52  Plato

Grain/Extract/Sugar

%    Amount    Name                          Origin        Potential SRM

62.0    11.00 lbs. Pale Malt(2-row)              America        1.036      2
  8.5    1.50 lbs. Brown Malt                    Great Britain  1.032    70
  2.8    0.50 lbs. Crystal 40L                  America        1.034    40
14.1    2.50 lbs. Munich Malt (Durst)          Germany        1.037    10
  5.6    1.00 lbs. Crystal 120L                  America        1.033    120
  7.0    1.25 lbs. Chocolate Malt                America        1.029    350

Potential represented as SG per pound per gallon.

Hops

Amount    Name                              Form    Alpha  IBU  Boil Time

0.65 oz.    Magnum-Domestic                  Whole  15.00  29.2  60 min.
  0.40 oz.    Goldings - E.K.                  Whole    6.00  2.6  10 min.

Extras

Amount      Name                          Type      Time

0.00 Unit(s)Whirlfloc                      Fining    15 Min.(boil)

Yeast

Wy1450, Wy1056, or DCL Yeast US-56 Fermentis American Ale

Mash Schedule

Mash Name:

Total Grain Lbs:  17.75
Total Water Qts:  23.00 - Before Additional Infusions
Total Water Gal:    5.75 - Before Additional Infusions

Tun Thermal Mass:  0.13
Grain Temp:        65.00 F

Step  Rest  Start  Stop  Heat    Infuse  Infuse  Infuse
Step Name            Time  Time  Temp    Temp  Type    Temp    Amount  Ratio

sacc                  0    60    155    155  Infuse  172      23.00  1.30

Total Water Qts:          23.00 - After Additional Infusions
Total Water Gal:            5.75 - After Additional Infusions
Total Mash Volume Gal:      7.17 - After Additional Infusions

All temperature measurements are degrees Fahrenheit.
All infusion amounts are in Quarts.
All infusion ratios are Quarts/Lbs.

When fermentation is complete, split 2 vanilla beans lengthwise.  Scrape all the seeds and “gunk” from them and add it to the fermenter.  Chop the beans into 2-3 in. long pieces and add them, too.  Leave in secondary 10-14 days, then taste.  You want the vanilla to be a bit on the strong side since it will fade.  If the vanilla flavor is adequate, rack to bottling bucket or keg and add approximately 375 ml. of Jim Beam Black bourbon.  You don’t need to use an expensive bourbon, and you don’t want to add a lot.  The beer shouldn’t scream “BOURBON!” at you. You should have an integrated flavor of the chocolatey porter, vanilla, and bourbon.  This beer does not benefit from extended aging.  I prefer it within a few months of brewing.  The FG should be in the mid-high 20s, so don’t worry about trying to get it lower.

All - thanks for the quick replies!

To add to the discussion, it is a imperial porter with coffee and cacao nibs.

Has anyone had Pizza Port’s Coffee Monster? This is a clone of Coffee Monster. Unfortunately, the IBU isn’t disclosed on their website.

The recipe calls for "any good attenuating, malt accentuating, low ester producing, ale strain. Perhaps WLP001/WY1056 would do.

That’s good additional info.  I found that when I made a coffee stout that I needed to cut back on the bittering to account for the bitterness of the coffee addition.  It took me a couple test batches to dial it in.  That may be what you need to do.    But what does the beer you want taste like?  Is it sweet, balanced, bitter?  We can’t help you unless you tell us what you’re going for.  You might also want to consider using WY1450 for it.

Denny, it is balanced, not too sweet and very porterish. The coffee and cacao is very present. It’s been a while since I had a sample (live in LAs Vegas - Pizza Port is in Oceanside, CA) but I don’t it recall being hoppy or bitter.

It calls for 50% Peruvian / 50% Indian coffee with the cacao nibs post fermentation (bagged in the bright tank) while cold and being carbonated for 48 to 72 hours.

The recipe is missing the coffee amounts also (although I am asking for it via email). I planned on 6 ounces of coffee but need a little advice on the cacao.

I’ve read here about soaking the nibs in vodka for a few days. I may do the same, and add the coffee slurry trough a cold press.

Your thoughts?

The best way I’ve found to add flavorings like coffee is to do it at packaging time.  Pour 4 2 oz. samples of the finished beer.  Add a different measured amount of coffee to each.  Pick the one you like best and scale that amount of coffee to the batch size.  Beats making a WAG in the fermenter.

Cacao nibs will add bitterness too. I made an imperial stout with cacao nibs that I wish I had cut the bitterness back just a little bit due to the 4 oz of cacao nibs in the secondary. It was a split batch with half receiving no nibs. If I had to guess I would say the chocolate version was one “notch” up in bitterness - maybe 10 ibu.