Myrcene Oil Discrepencies

I'm a little confused. In researching ideal flameout temperatures to maximize hop flavor/aroma, I read a recent article from beersmith on oils:

http://beersmith.com/blog/2013/01/21/late-hop-additions-and-hop-oils-in-beer-brewing/


Here, it explains that myrcene oil will volatize at 147*F, so of course adding to boiling wort will boil it off.

On the brew wiki, though, it reads:

"When boiled for longer periods, it yields the characteristic citrus and pine aromas of American craft beer..."

Isn't this conflicting?

maybe I should've posted under brew science?

The brew wiki quote is simply false. Myrcene diminishes exponentially the longer it's boiled. Early boil additions contribute virtually no myrcene to the finished beer. But Brad Smith is also wrong. The boiling point of myrcene is 333F, not 147F. However, you don't need to boil myrcene for it to volatilize. It will volatilize even at room temperature, but higher temperatures speed up the volatilization process dramatically. Unfortunately, there doesn't seem to be a simple answer to the question of at what temperature post-boil additions should be added. It's a matter of balancing the rate of extraction and the rate of volatilization, and as far as I know there hasn't been any serious investigation of either.

Some helpful key points on myrcene:

~Myrcene levels in beers, which were hopped at the beginning of the boil are around 0.13ppb, while beers which were hopped after wort cooling had about 66ppb – a 508x difference! A post-boil warm hop addition yielded myrcene levels of 0.82ppb - a 631x difference!~

~Whole hops can have as much as 70% more myrcene than pellets of the same variety, but that difference is flipped when the wort is hopped as only 5% of myrcene is extracted from whole hops compared to 17% from pellets.~

~Myrcene boils at about 167C (not F), but it volatilizes at every temperature from its freezing point up to boiling (more so the higher you go obviously).~

~The fragrance of myrcene is subdued to minimal levels with heat, and this prevents it from remaining prevalent after a boil or mash.~

~With a temperature of 147 degrees F, its flavor dissipates in much the same way as it's fragrance with high temperatures.~

~The highest levels of extractable myrcene are seen in fresh Pacific Northwest American pellet hops, such as Amarillo, Citra, Simcoe, Horizon, Centennial, Cascade, Nugget, etc. These tend to be great late addition hop choices for American IPAs. There are a few moderate myrcene % varieties from the same location which are still high total oil content and very high alpha such as Apollo, Columbus, Chinook, Summit, Bravo, Warrior, etc. These hops are great choices for early and middle additions when brewing American IPAs.~

~The lowest levels of extractable myrcene are seen in old European and/or Noble leaf hops, such Tettnanger, Saaz, Hallertauer, Fuggle, EKG, Spalt, Magnum, etc.~

Good stuff guys.

Anyone do any experimenting with adding flame out additions at different temps? I know there's an ongoing, enormous thread on that, but I just haven't gone through all of it yet.

I'm thinking about adding flame out hops just below 180, then another dose as it cools even more.

This is what I go by and I'm thrilled with the results:

Hot Hop Additions (Simmering / Boiling Temps)
Approx. 180-212 F. @ the full length of your boil

Warm Hop Additions (Not Simmering / Not Scalding Hot)
Approx. 100-160 F @ 20-60 minutes depending on cooling method; lesser than this isn't doing much

Cold Hop Additions (Dryhop Temps)
Approx. 65-68 F @ 5-14 day dryhop, whether single stage or staggered

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What also matters to me is how the hop additions are divvied in the recipe. I used to brew a lot of lowly bittering / heavy warm hop addition / moderate dry hop IPAs like this:

14% early
14% middle
43% late
29% dryhop

or

13% early
0% middle
50% late
37% dryhop

This type of emphasis yielded more of a fruity/juicy type of IPA. Still plenty bitter, but more juice-like and less beer-like, lacking that "clean" yet high bitterness.

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Presently, I prefer a completely different emphasis:

28% early
14% middle
28% late
30% dryhop

or

21% early
17% middle
28% late
34% dryhop

These schedules are more along the lines of Pliny, Tricerahops, and Head Hunter. Clean, smooth, bitterness yet with no sacrifice of flavor / aroma.

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Here is the legend:

90-60 min - early
45-25 min - middle
15-0 min - late
5-10 days - dryhop

The key to brewing beers like Pliny is fairly large additions at every slot. And that your only late additions are from the whirlpool. They don't waste hops on 20-15-10-5 additions. All of the IBUs are gained from 90-30, in a layered schedule for smoothness and complexity, whereas all of the potent aroma is gained from 0-DH.

Great info Bob. Very interesting to me to hear your results on this, because lately I haven't been totally satisfied with hopbursting and a huge emphasis on only late additions - I find it as lacking a certain smoothness, or clean bitterness that you mention ---which is exactly what I'm seeking. With great flavor of course. Hopbursting, though packed with flavor, still comes across as muddled to me.

A lot of people have been getting away from the 30 min additions, but many brewery recipes still use them, so there must be something to it after all. I threw together a recipe the other day with hop additions only at 60, 30, FO and dry hop, and I'm gonna roll with it after seeing some of your results.

I think it's likely that mid-boil additions are necessary to achieve very high levels of IBUs. Some of the iso-alpha acids imparted by bittering additions will be pulled out of solution by break material, which a later addition can help compensate for. Simply adding more hops at the beginning of the boil won't help if the wort is already saturated.

Great info with some good ideas/methods to consider and try. Thanks!

bobbrews said:

21% early
17% middle
28% late
34% dryhop

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I'm assuming these percentages are by weight. Wouldn't the first two numbers vary quite a bit depending on the alpha acid% of the hops being used, or do you play with the times until you hit the numbers?

Gavagai said:

I think it's likely that mid-boil additions are necessary to achieve very high levels of IBUs. Some of the iso-alpha acids imparted by bittering additions will be pulled out of solution by break material, which a later addition can help compensate for. Simply adding more hops at the beginning of the boil won't help if the wort is already saturated.

Click to expand...

There could be some truth to that. Or perhaps, staggering the early and middle additions could be providing a smoother type of bitterness (instead of adding everything at 90/60) while helping to change the flavor profile a bit. In either case, actual IBU concentration tops off at 90-110. So there is probably something in the way of flavor happening there. This is the reason I would not be scared of a recipe that stated 200-300 theoretical IBUs; as long as an appropriate amount of an appropriate hop is used at the appropriate slot.

What I researched this initially, I compared the % of total hop use in many different clone recipes. I found that for the huge majority, the IPAs I enjoy most use a lot of hops and focus on all four additions (dryhop, flameout, early, middle -- in that order).

Found Some guys master's thesis on hop oil extraction, it deals with dry hopping but there's a bit in there about myrcene.


Bobbrews: Any idea the method used to determine hop oil levels? 0.13 parts ber billion seems too good to be true. But i've never used a GC to figure out oil extractions.

kingwood-kid said:

I'm assuming these percentages are by weight.

Click to expand...

12 oz. total hops

21% early = approx. 2.5 oz.
17% middle = approx. 2.0 oz.
28% late = approx. 3.5 oz.
34% dryhop = approx. 4.0 oz.