Flavor/Aroma Calculations

Ingredients
1

Currently putting together a Belgian/Trappist Single recipe. Calculating bittering additions is pretty straightforward right? Alpha Acids to the desired IBU’s
I never really gave it any thought about how to calculate the flavor/aroma additions. Just added those as late addition/post boil while hoping for the desired effect and if it isn’t where I wanted it to be then make changes on the next iteration. This leads me to ask: How do you calculate flavor&aroma hops??

The following is what I mean

17 Gallon Batch Size
Bittering= 39grams Hallertau Magnum @14.8% AA 60mins for 24 IBU’s
                28grams Hallertau Magnum @ 14.8% AA 15mins for 8.5 IBU’s
Flavor= 56grams Styrian Goldings @ 3.5% AA 5mins for 1.6 IBU’s
Aroma= 56grams Styrian Goldings @ 3.5% AA whirlpool 30 mins @ 160* for 1.1 IBU’s

I know that the bittering will be fairly on target BUT how does one target the flavor/aroma??

2

If you want to maximize flavor or aroma without going overboard to where you are wasting hops (point of diminishing returns), you need a maximum of 0.8 oz/gallon (or I guess that’s 23 grams/gallon).

If you want a moderate amount of flavor or aroma, use 25-50% as much.

To calculate IBUs, including the same late additions:

IBU = oz * AA% * [sqrt(4.6*Boiltime)/V + sqrt(HStime)/V]

where
V is post-boil volume in gallons,
Boiltime is in minutes, and
HStime is post-boil hop stand (or whirlpool) time in minutes that it hangs around between about 150-190 F.

So in your case, by my calculations, you’ll end up with about 45 IBUs, a little higher than you had calculated but we’re both in about the right ballpark, someplace between 35-45 is what you’ll end up with.

Yes, that’s my method, based on… well, I could tell you, but it’s kind of a mess.  Bottom line: It’s my method.

Cheers.

EDIT: When I double-checked my math, I got 36.  Now I’m gonna have to triple-check and figure out where I screwed up.  But anyway.  Yeah.

EDIT2: Yeah, it’s 36.  The + sign in my formula is no longer actually a +.  I’ve changed it to an either/or thing, depending on whether boiled or whirlpooled (hop stand).  Easier this way.  Should look something more like:

IBU = oz * AA% * [sqrt(4.6*Boiltime)/V or sqrt(HStime)/V]

I’m pretty satisfied with this version, don’t think I’ll tweak it much anymore.  It works for typical worts between about 1.040 and 1.080.  Above and below those points, change the 4.6 to like 5.2 or 4.0 to still arrive in the right ballpark.  This is an estimation method, not an exact answer, but will match reality within a few points every time as long as your OG isn’t crazy high or low.  I dare anyone who is interested to try it out on a few recipes and compare vs. Tinseth (at least for boil additions, there is no Tinseth for whirlpool additions).

Anyway… I hope this helps some soul out there.

3

I appreciate the response but tbh I won’t use an equation. I let software figure out the bittering and maybe that’s where I didn’t make myself clear.
I don’t think there is a software widget to calculate the nuances of flavor or aroma.
So how does one put a quantity of hops on either of those? (flavor/aroma). We go through the motions of creating a recipe and can precisely target bittering ibu’s but not how much hops are needed for flavor & aroma. Apparently they are subjective only.

4

It’s just iterative for me. I start with the hop schedule that seems to work for a recipe I like, substituting one hop for another adjusting for IBU impact.

I tend to use very similar base grain bills and sub in/out specialty grains, hops, and yeast to create variety.

Once the beer is served I decide if what I did was effective. If so, walla. If not, make a note and adjust at the next iteration.

Problem is I have already brewed two beers since I brewed the beer in question. So, at my normal 3 week brewing schedule, it can take months to wedge the rebrew with those exact hops into the pipeline (if it ever gets rebrewed).  By then my interest has moved on to the next ‘best beer I’ve ever planned to brew’.

5

By taking notes religiously, that’s my solution.  If the flavor or aroma was not what I was expecting, I add more or less hops the next time.  That’s pretty much it.

There are just so many problems with late hopping.
Freshness of hops, type of hops, when to add, how long to leave in, at what temperature, when and how to dry hop, what yeast, and on and on…meh.

And that’s not to mention that every time you turn around there is a new product on the market that is supposed to improve flavor and aroma.  Double meh…

So, change one part of your process and you may or may not have changed them all.

Targeting IBU’s is hard enough.  Flavor and aroma are a disaster.  So I just try and keep the process simple and repeatable.

6

It depends significantly on the hop variety. When I’m brewing a batch where I want to add a subtle hop aroma, I use 1 oz at flameout of a hop variety that isn’t really “In your face” (i.e., noble hops, hops with noble character like Sterling or Motueka, UK hops like Goldings, etc.). I brew 2.5 gallon batches, so double this number for a 5 gallon batch.

If I used the same quantity of Citra, Mosaic, or some other “IPA Hop” with a strong character, then the aroma would go from subtle to significant at the same hopping rates.

Basically, pick a hop that fits the style and err on the low side for a non hop-forward beer, or on the high side for a hop-forward style. Then adjust going forward. There is no magic formula for flavor/aroma additions, and a lot of this just comes from experience and trial-and-error. Thankfully the trial-and-error can be quite tasty  ;D

7

When you are adding hops at flameout, do you do a hopstand/whirlpool, or start chilling right away?

8

I only hopstand for IPA’s. Otherwise, I start chilling right away. I still get a noticible aroma contribution. My immersion chiller isn’t the most efficient, so YMMV if you have a Hydra or CFC or something that can chill a lot faster than I can.