Author Topic: Dry Hopping research - Interesting  (Read 6499 times)

Offline dimik

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Re: Dry Hopping research - Interesting
« Reply #15 on: December 04, 2012, 11:52:12 AM »
Oh sweet! Thanks for posting this. Gonna read it Thursday or Friday.
I only just glanced through this and it's some really good information. Would be nice if we started gathering a library of homebrew literature that's based on solid science and experimentation and make it available for everyone.
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Offline bwana

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Re: Dry Hopping research - Interesting
« Reply #16 on: December 04, 2012, 12:06:22 PM »
Wow. There is alot of info there! I wish it was in a book!

Offline kramerog

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Re: Dry Hopping research - Interesting
« Reply #17 on: December 04, 2012, 12:29:04 PM »
Section 1.3.4 provides support for the theory that first wort hopping provides a mellow bitterness because of the precipitation of polyphenols with protein during the boil.   This section doesn't address how aroma and flavor survives the boil.
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Online hopfenundmalz

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Re: Dry Hopping research - Interesting
« Reply #18 on: December 04, 2012, 01:08:46 PM »
Section 1.3.4 provides support for the theory that first wort hopping provides a mellow bitterness because of the precipitation of polyphenols with protein during the boil.   This section doesn't address how aroma and flavor survives the boil.

The aroma can come through if certain compounds that are soluble (linalool and geranol) combine with the sugars for form glycosides. The yeast is thought to break the bonds to get the sugars. The compounds left are the refined aromas the German brewers like. The essential oils like myrcene are only had through dry hopping, which the Germans do not typicaly do.*

* Not a chemist but this has been something of interest.

Read the post from 2/16/2012 titled linalool.
http://beersensoryscience.wordpress.com/category/hop-flavor/
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Offline kramerog

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Re: Dry Hopping research - Interesting
« Reply #19 on: December 04, 2012, 01:52:42 PM »
Section 1.3.4 provides support for the theory that first wort hopping provides a mellow bitterness because of the precipitation of polyphenols with protein during the boil.   This section doesn't address how aroma and flavor survives the boil.

The aroma can come through if certain compounds that are soluble (linalool and geranol) combine with the sugars for form glycosides. The yeast is thought to break the bonds to get the sugars. The compounds left are the refined aromas the German brewers like. The essential oils like myrcene are only had through dry hopping, which the Germans do not typicaly do.*

* Not a chemist but this has been something of interest.

Read the post from 2/16/2012 titled linalool.
http://beersensoryscience.wordpress.com/category/hop-flavor/

Neither article indicates that glycosides are formed in the wort although that is not surprising as the first article is about dry hopping and the author of the second article indicates that most of the research is in German.  Both articles indicate that the glycoside can be cleaved by acid.
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Offline kramerog

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« Last Edit: December 05, 2012, 08:58:09 AM by kramerog »
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Re: Dry Hopping research - Interesting
« Reply #21 on: December 04, 2012, 03:20:53 PM »
Section 1.3.4 provides support for the theory that first wort hopping provides a mellow bitterness because of the precipitation of polyphenols with protein during the boil.   This section doesn't address how aroma and flavor survives the boil.

The aroma can come through if certain compounds that are soluble (linalool and geranol) combine with the sugars for form glycosides. The yeast is thought to break the bonds to get the sugars. The compounds left are the refined aromas the German brewers like. The essential oils like myrcene are only had through dry hopping, which the Germans do not typicaly do.*

* Not a chemist but this has been something of interest.

Read the post from 2/16/2012 titled linalool.
http://beersensoryscience.wordpress.com/category/hop-flavor/

Neither article indicates that glycosides are formed in the wort although that is not surprising as the first article is about dry hopping and the author of the second article indicates that most of the research is in German.  Both articles indicate that the glycoside can be cleaved by acid.

The thinking on FWH is that hop compounds are combining in the wort and make it through. That is what I was pointing out. A few pros have talked about this, Matt B at the NHC IIRC, and a few have said that additions in the 30 minute range are best for glycoside production. The Germans want at least 10 min. in the boil.

Once again - not a chemist, but have wondered about flavor and aromas for making German styles.

Edit - first link was not working. Have already seen the second.
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Offline tschmidlin

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Re: Dry Hopping research - Interesting
« Reply #22 on: December 04, 2012, 09:53:42 PM »
Kinda looks like I'm doing the right thing...I don't weight the hop bags but I do swirl the fermenter a couple times a day.

It's the time Denny, not the stirring that's the real eye opener here. The stirring is being proposed as an even better/faster way of extraction in a commercial setting.....we don't have or even want the ability to continually agitate in a homebrew situ. Look at the graphs on page 40 & 41. After a day, you're actually decreasing your aroma compounds. It's really some pretty unexpected results. 
i hesitate to read too much into this.  I have not read it as carefully as I want to yet, but here are some initial impressions.

For Figures 7 and 8 - there are no error bars.  This looks like a single experiment.  The final (4th) points are also too far from the next (3rd) one - what appears to be a downward trend here could simply be a blip in the data and it could increase after 24 hours.  If there were additional data in between that showed the same thing it is potentially more interesting.  We also don't know if it is actually the slow and steady decline shown or if it declines sharply and is steady to the final point.  Another unanswered question - how much of the decline could be attributed to evaporation of the oil?  If it is simply the linalool filling the headspace, perhaps not seen in the others because they have a higher evaporation temperature, then the real thing to do is minimize headspace during dry hopping.

Another issue - compare Figure 5 to Figure 8A - both have linalool concentration at 24 hours around 0.2 ppm.  Now compare Figure 6 to Figure 7A - both have myrcene concentrations at 24 hours, but one is around 0.1 ppm and the other is around 0.4 ppm, four times higher.  Why the discrepancy?

They did at least some of these experiments pretty warm and with constant stirring - if you recirculate before you blow off the yeast that creates it's own problems and will affect dry hopping.  If you do it after, you need to crash/chill and blow off the yeast, heat and recirculate the beer to dry hop, then chill for carbonation and packaging.  With the energy and time required to heat and chill large batches of beer, will there really be a savings?  I don't know.

It's really interesting stuff and I need to do a more thorough read through.  I'm not sure it will have a practical effect on anything in a brewery.  As usual, I want more data ;D
Tom Schmidlin

Offline jimrod

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Re: Dry Hopping research - Interesting
« Reply #23 on: December 05, 2012, 12:45:31 AM »
i wish someone would just give me the Cliff Notes. The very short version.
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Offline kramerog

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Re: Dry Hopping research - Interesting
« Reply #24 on: December 05, 2012, 09:01:24 AM »

It's really interesting stuff and I need to do a more thorough read through.  I'm not sure it will have a practical effect on anything in a brewery.  As usual, I want more data ;D

Does anyone want to comment on the higher polyphenol levels with mixing?
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Offline benamcg

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Re: Dry Hopping research - Interesting
« Reply #25 on: December 06, 2012, 10:12:00 AM »
Great work and an interesting read.  Whereas decreased dry hop contact time and increased aroma, bittering is great, I am not sure that I like the idea of increased astringency.....

Offline gandelf

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Re: Dry Hopping research - Interesting
« Reply #26 on: December 11, 2012, 06:29:51 AM »
I started torpedoing my hoppy ales about six months ago. Now, almost all of my ales get the treatment. I have tried ALL the techniques to get hop aroma and flavor into beer and for me, nothing compares to a torpedoed ale. The torpedo process also filters, my hoppy ales are now almost bright.
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Re: Dry Hopping research - Interesting
« Reply #27 on: December 11, 2012, 08:30:12 AM »
I started torpedoing my hoppy ales about six months ago. Now, almost all of my ales get the treatment. I have tried ALL the techniques to get hop aroma and flavor into beer and for me, nothing compares to a torpedoed ale. The torpedo process also filters, my hoppy ales are now almost bright.

Can you describe your torpedo set up? Pictures would be great.
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Offline gandelf

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Re: Dry Hopping research - Interesting
« Reply #28 on: December 11, 2012, 09:54:49 AM »
I started torpedoing my hoppy ales about six months ago. Now, almost all of my ales get the treatment. I have tried ALL the techniques to get hop aroma and flavor into beer and for me, nothing compares to a torpedoed ale. The torpedo process also filters, my hoppy ales are now almost bright.

Can you describe your torpedo set up? Pictures would be great.

Sure, if you email me, I can attach a pic of my v1.0 hop rocket and v2.0 whole house filter housing (more hop complicity) utilized as a torpedo. I'll outline how I sanitize, purge with co2 and plumb it with a corny.
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Offline jeffy

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Re: Dry Hopping research - Interesting
« Reply #29 on: December 11, 2012, 11:11:35 AM »
I started torpedoing my hoppy ales about six months ago. Now, almost all of my ales get the treatment. I have tried ALL the techniques to get hop aroma and flavor into beer and for me, nothing compares to a torpedoed ale. The torpedo process also filters, my hoppy ales are now almost bright.

Can you describe your torpedo set up? Pictures would be great.

Sure, if you email me, I can attach a pic of my v1.0 hop rocket and v2.0 whole house filter housing (more hop complicity) utilized as a torpedo. I'll outline how I sanitize, purge with co2 and plumb it with a corny.

But what about the rest of us?
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