International Aromatic Unit

[BrewinLou]

How come there is not one? The equipment is there to do it. It changes drastically over time, so does bitterness. With the popularity of APA, IPA, DIPA, and the IIPAs there should be.

[HinduKush]

How come there is not one? The equipment is there to do it. It changes drastically over time, so does bitterness. With the popularity of APA, IPA, DIPA, and the IIPAs there should be.

Go ahead and invent one. You have a gas chromagraph at BBC don't you?

[BrewinLou]

Go ahead and invent one. You have a gas chromagraph at BBC don't you?

No, but there are several friendly distillers a 20 minute drive away that do, and they like beer too. Hmmm

[HinduKush]

No, but there are several friendly distillers a 20 minute drive away that do, and they like beer too. Hmmm

Big as you guys are and you don't have one in your lab? What do you use for ibu, color, abv, etc?

[drewseslu]

Here's a little blog post I wrote about using Ounces Per Barrel and a ratio of OsPB to IBUs in order to describe the relative hoppiness of one beer versus another similar beer.
It isn't perfect, but can be useful.
http://mattinglybrewing.blogspot.com...-with-opb.html

[BrewinLou]

Thats pretty cool Drews. I was thinking something like that. Maybe with a little analysis one could factor in the aroma differences between say a Simcoe and Fuggle. The shear stinkiness factor, some hops seem to have a lot more aroma then others.

[jwalts]

I typically create a "hop bill" by defining a lbs/bbl for each flavor/aroma hop, calculating their bitterness contributions in IBUs and then adding enough bittering hops to make up the difference between my target bitterness and what's already in there. I think it would eventually be cool to use oil content(s) instead of weight per barrel, though, because it would automatically compensate for hop variety (my assumption is that oil profiles are what differentiate varieties from each other).

I started a database of common hop varieties and their typical oil levels. I believe my numbers are from a HopUnion Directory of Hop Data. Anyway, you can download it at http://sites.google.com/site/republicbrewpub/ - the file is called "Hop Compounds.xls". It's not very thorough... yet!

Joe

[Jaltwies]

I think this would be a great thing...as aroma components are typically overlooked industry-wide as high volume/high temperature processing can remove many of the components. Only one of the big four essential oil components is stable over 120F (heat of vaporization) and two dissappear at less than 105F so drying and processing at temps higher that this will really reduce the aromatic impacts of what are flowers, folks.

Low and slow...like good BBQ. We're doing this at Gorst Valley (chromatographs galore)...but ultimately as our tagline says..."The proof is in the pint"

[william.heinric]

Many stat sheets for hop lots come with a total oil content (as ml/100g, I believe). Many are fractionated beyond that point as well. It seems to be that you could plug the info into a spreadsheet and correlate the data with qualitative tasting.

I designed a recipe designer to do this, but I haven't had the opportunity to either use the program or check it against sensory analysis. I'd like to know if there are any formulae that describe the utilization and destruction of the aroma oils during the boil, fermentation, aging, and packaging.

Bill

[BrewinLou]

I have not found one yet. Don't forget filtration. Time seems to be the biggest offender to destroying aromas, at least per my taste buds.

[Jaltwies]

There are 4-5 main oil components that comprise the categories for hop aroma. Three of the four oils have heats of volatization less than 120 degrees F (one has a HV of 250F) Myrcene makes up most of the oil complex and contributes nothing to sensory (even when oxidized)...

So that means "traditional" processing techniques (drying and pelletizing at 140F) can deplete the more delicate oil components. Keeping drying temps below 110F and pellet die temps below 100 will keep the more interesting oil aromas intact that many brewers have not had the pleasure of experiencing.

General oil content is reported as ml/100grams and is measured via distillation. Fractionating the oils further requires gas chromatography...