The Great Whirlpool Hopping Experiment

I know of a local brewery that has a sought after IPA, They swear by the 150f hop stand over 30 min

 

Sorry, it's actually 155f

 

Do you know what hops they use in the WP?

 

Citra

 

Thanks, that's good to know.

My intuition tells me that each hop will have a different 'sweet spot' in the WP. ie Citra might be best at 155F, Cascade at 180F, etc....
Might be able to correlate with oil contents. Here's what Hop Union has for Citra. http://hopunion.com/citra-brand-ycr-394-cv/
Citra
Total Oil 2.2 - 2.8 mL / 100g
Myrcene 60 - 65% of total oil
Humulene 11 - 13% of total oil
Caryophyllene 6 - 8% of total oil
Farnesene < 1% of total oil

So maybe ~150F is a good WP temp for hops that have a similar hop oil ratio as this? heavy in myrcene & Caryo and light in Farnesene

We used Cascade and Centennial for this experiment. The Centennial profile looks closer to Citra than the Cascade.
Cascade
Total Oil 0.8 - 1.5 mL / 100g
Myrcene 45 - 60% of total oil
Humulene 10 - 16% of total oil
Caryophyllene 3 - 6% of total oil
Farnesene 4 - 8% of total oil

Centennial
Total Oil 1.5 - 2.5 mL / 100g
Myrcene 45 - 60% of total oil
Humulene 10 - 18% of total oil
Caryophyllene 4 - 8% of total oil
Farnesene < 1% of total oil

Does anyone remember the article that had listed the vapor temperatures for the different hop oils? I can't find it off hand.

 

Wow, great info!

 

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

Here's a summary of the boiling points:
Myrcene – (147 F/63.9 C boil point)
Humulene – (210F/99C)
Caryophellene – (262F/129C)
Farnesene – (203-257F/95-125C)

 

150-160F is my default steep temperature range. There is low isomerization with good extraction of hop oils in that range. You can steep for an hour at this temperature while producing very little bitterness from the steeped hops. A 20-30 minute steep is normal for me. Sometimes I do 45-60 minutes. I steep even if I don't add flame out hops. There are still plenty of oils that can be extracted from 10 and 5 minute hops. The wort clears significantly during this chill to 150-160F then steep phase.

 

I found this ref as well that Jack posted awhile back...

At the 2010 NHC, James Altweis provided flash point temperatures for the ‘top 4’ essential oils:
· Myrcene: 103°F
· Caryophyllene: 200°F
· Farnesene: 79°F
· Humulene: 110.2°F

This link might take you to the presentation. (I say might because it was cached)
http://www.ahaconference.org/wp-content/uploads/presentations/2010/Hop_Quality-James_Altweis.pdf

These are very different temperatures from the beersmith blog ref. However, James Altweis refers to these as flash points, which seems odd to me because a flash point is typically the lowest temperature a liquid can vaporize and ignite. I don't think he meant to use that term.

According to Wikipedia the (avg) boiling points at atm pressure are....
Myrcene: 332F
Caryophyllene: 490F
Farnesene: 257F
Humulene: 225F

I don't know what to believe....

 

Dave, It seems to me that James Altweis does indeed mean flashpoint since he previously discussed:

‡”Most of the essential oils flash at temps well below 140 F

· Oil fraction can dissociate and volatilize at these temps”


As to whether he is stating the correct temperature values I really do not know.

Cheers!

 

Flash points are lower than the boiling points. Take iso-octane for an example we have some experience with (reference for gasoline) flashpoint is -7C, boiling point is 98C. We all know we can get a strong aroma from gasoline at room temperature, and the vapors are flammable (as an aside, winter blends have more of the lighter compounds such as pentane that have a much lower flashpoint to aid cold starts).

http://www.caslab.com/2_2_4-Trimethylpentane-Isooctane.php5

We also know that a spill of gasoline on the concrete can disapate rapidly as it flashes off, no boiling required.

Much has been said about wet hoped beers. Some hop growers are now drying in the 125-130F range to help preserve more volatile compounds.

When you put your hops into a boil, the explosion of aroma that fills the brew space are the volitile compounds flashing off. You don't have to boil those for them to disappear, sort of like the gasoline example.

Read the next to last comment by James A in the BeerSmith article. Could that be James Altweis?
http://beersmith.com/blog/2013/01/21/late-hop-additions-and-hop-oils-in-beer-brewing/

 

Good points, that a good way to explain it. So can it be concluded that since we can smell the hop oil vapor (aroma) at room temperature there probably is no good WP temperature for any of these oils. In other words anything over room temperature is going to be too hot.
One thought that crossed my mind is that we do WP at atm pressure, what if we do whirlpooling at low temps and higher pressures. Like maybe in a pressure cooker? Would that help maximize how much of the hop oils we keep trapped in the wort?
Or maybe there is some flashpoint temperature as Altweis points out. If so, how do we figure out what they are? Altweis doesn't give a reference for his temperatures in his presentation.

 

An extract from the James A comment:

“…Linalool, geraniol, citronella, amylacetate, carvone, etc are the real character builders.”

It would interesting to know the flashpoint temperatures for these oils.

Does anybody know the answer?

Cheers!

 

That is why dry hopping works, all I've got for that.

No information on that Jack.

 

There is that one out there. Heck, I do it! What compounds make it through I don't know, and what do the yeast transform?

Many questions to be looked into with research, butvthatvtakes time and money.

 

The boiling point for linalool is 390F. The flash point is 131F.

-Things I learnt from Wikipedia.

 

Y'all a bunch of nerds.

(coming from the nerdiest math major who ever was... a term of endearment)

 

The old saying of "it takes one to know one" comes to mind!

Cheers!