Hops AA with respect to flavor and aroma

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Hops AA with respect to flavor and aroma

Postby gclancy » Sat Jan 22, 2005 6:20 pm

Hello Everyone. Do hops AA percentage affect the intensity of flavor and aroma, or just bittering? For example, can I expect greater hop aroma from the same amount of hops with a higher AA?

Thanks for any info.
-Greg
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That's a Good Question

Postby BillyBock » Sun Jan 23, 2005 10:05 am

Gclancy: that's a good question. I don't know off the top of my head...I'll have to defer to my library for answer. I'll repost when I find out. However, I would think the AA are significant only when they isomerize for bittering. I could've sworn there are other components in hops, dependent on variety, that will tell you whether they're good for adjusting flavor and aroma. Which is one of the reasons everyone raves about noble hops. There's just something different about them that makes them suitable for the application. Anyway...off to the library.

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Postby Dogger Dan » Sun Jan 23, 2005 4:13 pm

Alpha Acids are all about bittering

Beta Acids are aroma unless they are oxidized


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Myrcene and friends

Postby jeff » Sun Jan 23, 2005 7:02 pm

The bitterness of hop additions are contributed by soft resins such as alpha acid and they account for less than 15% of the hop cone mass. Flavor and aroma are supplied by essential oils that exist in even smaller amounts in the hop cone. The most significant compounds that play a role in the flavor and aroma in beer include Myrcene, Humulene, Caryophyllene and Farnesene. They are very easily driven off by boiling thus their contribution is encouraged by limited or no boiling; as in the case of dry hopping. It is these essential oil compounds that are credited with the floral, spicy and/or grassy aromas and flavors that come from hops and not the alpha and beta acids responsible for bittering.
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Late Hop Additions

Postby BillyBock » Mon Jan 24, 2005 7:57 am

Gclancy: I reviewed the chapters on hops in "Designing Great Beers," by Ray Daniels. Jeff beat me to the punch and is correct. There is no direct translation between AA and aroma/flavor because aroma/flavor and bittering are caused by essential oils and soft resins, respectively. You would need to compare the level of essential oils between hop varieties to get a more direct translation. This book is a good source for this type of info and is an excellent resource to have.

In general, for a given flavor/aroma hop addition, if you add more then you'll get more flavor/aroma. Few analytic tools are within the reach of the homebrewer or craftbrewer to predict the quantity of hop aroma or flavor they'll get in a finished beer, such as chromatography. Neither alpha acids nor hop oil as a percentage of hop weight have proven to provide effective control. So what's a homebrewer to do?

One option is to use hop extracts--it would allow you to really control the late-hop addition character. These extracts contain the essential oils in a concentrated liquid form. You add them to taste in a finished beer and then can reproduce your results in the future based upon this known concentration.

Another option is to study the style of beer you're brewing and follow the same practices. If you want to brew an authentic Czech Pilsner, you wouldn't be caught dead using anything other than Saaz for all hop additions.

A final option is just trial-and error. Generally in a 5 gal. batch you'll use 0.25 to 1.0 ounces per late-hop addition; dry-hopping amounts may be higher, 1 to 2 ounces. If you find you're not getting the intensity that you want increase the amount used, or add another late-addition to your hopping schedule. It's not unheard of to have 3, 4, or 5 late hop additions for flavor/aroma.

Hope this helps you on your quest.

Brew on!

v/r
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If you decide to use hop oil...be carefull!

Postby Brewer2001 » Tue Jan 25, 2005 1:13 pm

Greg,

I would make a "hop tea" by steeping, not boiling your aroma hops and adding them to your maturation vessel (secondary...I hate that word) or your racking vessel. It just depends on how soon you want the beer to blend.
Remember, as Jeff and Billy stated, the aromatic compounds are volitile and will be driven off by excess heat.

As for hop oil, first hand account. In one brewery where I was working we installed a 'new', used 20 barrel unitankthat had some problems. To try and salvage 18+ barrels we dosed in about 2 ozs. of hop oil. It flavored the entire batch (18 barrels = 558 gallons). So if you use oil add it by the drop and taste after each one.
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Postby Dogger Dan » Tue Jan 25, 2005 10:29 pm

Yep,

That Iso Hop is large,

a little goes a long way, less is more

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