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General Category => Ingredients => Topic started by: Alewyfe on December 04, 2012, 06:45:36 AM

Title: Dry Hopping research - Interesting
Post by: Alewyfe on December 04, 2012, 06:45:36 AM
Anybody read this thesis? Any thoughts? I noticed the author is scheduled to present this data at the World Brewing Congress Portland 2013. Ran across the info while I was perusing Indie Hops' blog.

http://ir.library.oregonstate.edu/xmlui/bitstream/handle/1957/34093/Wolfe_thesis.pdf?sequence=1

Title: Re: Dry Hopping research - Interesting
Post by: yso191 on December 04, 2012, 07:24:38 AM
Anybody read this thesis? Any thoughts? I noticed the author is scheduled to present this data at the World Brewing Congress Portland 2013. Ran across the info while I was perusing Indie Hops' blog.

http://ir.library.oregonstate.edu/xmlui/bitstream/handle/1957/34093/Wolfe_thesis.pdf?sequence=1

Interesting.  I think I'll go out and agitate the Belgian Imperial IPA I'm dry hopping in the garage.  That might be the closest homebrewers can come to stirring.

Steve
Title: Re: Dry Hopping research - Interesting
Post by: hopfenundmalz on December 04, 2012, 01:33:50 PM
Thanks for posting that link. Need another pot of coffee to read through the rest, but good stuff.

Edit. Looks like those that say you get differences in pellets and whole cones are right. This may also show why the Sierra Nevada torpedo has proved usefull for them.
Title: Re: Dry Hopping research - Interesting
Post by: thebigbaker on December 04, 2012, 02:07:23 PM
Thanks for the link.  Very interesting indeed. 
Title: Re: Dry Hopping research - Interesting
Post by: blatz on December 04, 2012, 02:16:38 PM
wow - thanks for posting.  am going to read it, but its gonna take a while...
Title: Re: Dry Hopping research - Interesting
Post by: morticaixavier on December 04, 2012, 04:27:52 PM
Insight in how to get rid of that unpleasant onion/foot aroma with certain hops!

Quote
[...]it had been shown that adding granular copper dramatically reduced the presence of currant-like and onion aromas in beer[...]
Title: Re: Dry Hopping research - Interesting
Post by: erockrph on December 04, 2012, 05:06:09 PM
Insight in how to get rid of that unpleasant onion/foot aroma with certain hops!

Quote
[...]it had been shown that adding granular copper dramatically reduced the presence of currant-like and onion aromas in beer[...]

Hmmm... looks like a Summit/BB IPA may be in the works...
Title: Re: Dry Hopping research - Interesting
Post by: Alewyfe on December 04, 2012, 05:42:04 PM
WOT? No comments on the possibility that you may be able to shave "days" off your dry hopping regimen?

The author makes the conclusion that dry hopping (unstirred) for more than 6 hours (with pellets, it was longer for cones) is accomplishing little in the way of additional aroma, and that extended periods of dry hopping are actually counter productive. Torpedo, Randall, Rocket...all used to provide increased aroma.
Could this partly be because of the shorter contact time with the hops?

Also, dry hopped hops still have all their bittering compounds in tact....Could we throw 'em in the freezer and use to bitter the next batch??? I always enjoy saving a few bucks.

I'm planning some experimentation soon.
Title: Re: Dry Hopping research - Interesting
Post by: denny on December 04, 2012, 05:44:11 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.
Title: Re: Dry Hopping research - Interesting
Post by: hopfenundmalz on December 04, 2012, 05:49:38 PM
I had seen references to the aromatics being extracted in 24 hours. Much new stuff here to read and understand.
Title: Re: Dry Hopping research - Interesting
Post by: morticaixavier on December 04, 2012, 05:51:56 PM
I have for sure noticed that if I drop a bag of hops in the keg and shake to carb it immediatly has some hop aroma. and I don't notice a significant increase the next day so that actually makes sense to me. by rocking the keg with the hops in there I am extracting most of what will be extracted in just a few minutes/hours. nice.
Title: Re: Dry Hopping research - Interesting
Post by: Alewyfe on December 04, 2012, 05:55:38 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. 
Title: Re: Dry Hopping research - Interesting
Post by: yso191 on December 04, 2012, 06:12:38 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.

Yes.  I just changed my current plan.  As I mentioned above, I've got a Belgian Imperial IPA being dry hopped right now, due to be kegged on Friday.  I am going to add a couple of ounces of Citra that morning before I transfer.

Steve
Title: Re: Dry Hopping research - Interesting
Post by: hopfenundmalz on December 04, 2012, 06:26:19 PM
I have a Bitter on tap that tastes very British. One thing I decided to do was only dry hop for 3 days, as that is about the time the hops would have in the cask before it is empty. Pulled the hops out after 3 days, and it tasted very familiar. 

Also had British malts, hops, WLP-002 and the pale ale water profile with lots of sulfates. :)
Title: Re: Dry Hopping research - Interesting
Post by: erockrph on December 04, 2012, 06:32:33 PM
It will probably be a while before I can digest all of this, but it sounds like dry-hopping overnight in my bottling bucket, then bottling the next day, may be worth a try sometime soon. Heck, it may be worth a try as a second wave of dry-hopping even if I've done one "traditional" round of dry-hopping in the fermenter.
Title: Re: Dry Hopping research - Interesting
Post by: dimik on December 04, 2012, 06:52:12 PM
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.
Title: Re: Dry Hopping research - Interesting
Post by: bwana on December 04, 2012, 07:06:22 PM
Wow. There is alot of info there! I wish it was in a book!
Title: Re: Dry Hopping research - Interesting
Post by: kramerog on December 04, 2012, 07:29:04 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.
Title: Re: Dry Hopping research - Interesting
Post by: hopfenundmalz on December 04, 2012, 08:08:46 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/
Title: Re: Dry Hopping research - Interesting
Post by: kramerog on December 04, 2012, 08:52:42 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.
Title: Re: Dry Hopping research - Interesting
Post by: kramerog on December 04, 2012, 08:57:00 PM
Summary of the research from the sponsors http://inhoppursuit.blogspot.com/2012/02/more-aroma-oil-faster-dry-hopsters-holy.html (http://inhoppursuit.blogspot.com/2012/02/more-aroma-oil-faster-dry-hopsters-holy.htm) and http://inhoppursuit.blogspot.com/2011/07/hop-oil-is-bigger-better-preview-of.html (http://inhoppursuit.blogspot.com/2011/07/hop-oil-is-bigger-better-preview-of.html)

P.S. fixed link
Title: Re: Dry Hopping research - Interesting
Post by: hopfenundmalz on December 04, 2012, 10:20:53 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.
Title: Re: Dry Hopping research - Interesting
Post by: tschmidlin on December 05, 2012, 04:53:42 AM
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
Title: Re: Dry Hopping research - Interesting
Post by: jimrod on December 05, 2012, 07:45:31 AM
i wish someone would just give me the Cliff Notes. The very short version.
Title: Re: Dry Hopping research - Interesting
Post by: kramerog on December 05, 2012, 04:01:24 PM

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?
Title: Re: Dry Hopping research - Interesting
Post by: benamcg on December 06, 2012, 05:12:00 PM
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.....
Title: Re: Dry Hopping research - Interesting
Post by: gandelf on December 11, 2012, 01:29:51 PM
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.
Title: Re: Dry Hopping research - Interesting
Post by: hopfenundmalz on December 11, 2012, 03:30:12 PM
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.
Title: Re: Dry Hopping research - Interesting
Post by: gandelf on December 11, 2012, 04:54:49 PM
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.
Title: Re: Dry Hopping research - Interesting
Post by: jeffy on December 11, 2012, 06:11:35 PM
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?
Title: Re: Dry Hopping research - Interesting
Post by: blatz on December 11, 2012, 06:40:22 PM
Yeah - I'd love to see how it's done!