[denny]

The end of fermentation addition enhances linalool, geraniol, and citronellol. Recently I read that those are some of the most volitile aroma compounds in beer. That agrees with your observation.

Out of curiosity, where did you get that information from? I'm of the opinion that the main benefit of dry-hopping at the end of fermentation is that less oils are pulled out of solution by adsorption to falling trub. The boiling points of the major sesquiterpine aroma compounds that we attribute to hop aroma (including the ones you mention above) are all above the boiling point of water. I question the old brewing adages regarding the volatility of these compounds.

Stan Hieronymus has referenced it in a Zymurgy article, among other places.  I experienced the increased geraniol, which is why I now rack to secondary before dry hopping.

[hopfenundmalz]

The end of fermentation addition enhances linalool, geraniol, and citronellol. Recently I read that those are some of the most volitile aroma compounds in beer. That agrees with your observation.

Out of curiosity, where did you get that information from? I'm of the opinion that the main benefit of dry-hopping at the end of fermentation is that less oils are pulled out of solution by adsorption to falling trub. The boiling points of the major sesquiterpine aroma compounds that we attribute to hop aroma (including the ones you mention above) are all above the boiling point of water. I question the old brewing adages regarding the volatility of these compounds.

Lots of reading of what Stan Hieronymus has to say about bio transformations. You can find some of his referrences online. Also some statements by industry people.

[erockrph]

The end of fermentation addition enhances linalool, geraniol, and citronellol. Recently I read that those are some of the most volitile aroma compounds in beer. That agrees with your observation.

Out of curiosity, where did you get that information from? I'm of the opinion that the main benefit of dry-hopping at the end of fermentation is that less oils are pulled out of solution by adsorption to falling trub. The boiling points of the major sesquiterpine aroma compounds that we attribute to hop aroma (including the ones you mention above) are all above the boiling point of water. I question the old brewing adages regarding the volatility of these compounds.

Stan Hieronymus has referenced it in a Zymurgy article, among other places.  I experienced the increased geraniol, which is why I now rack to secondary before dry hopping.

I've read and listened to many of Stan's articles and presentations on the topic, as well as many of his source materials and published studies. What Stan was referring to was the biotransformation that happens by the yeast, which can indeed convert linalool to geraniol. What is interesting is that there are other studies which show that yeast also convert geraniol to linalool as well. The end result of biotransformation is probably going to look different based on yeast strain, starting oil content of your hops, etc. And by getting most of your yeast out of suspension before starting your dry hops, you take biotransformation out of the equation and probably increase your repeatability and predictability in your dry hopping.

What I'm calling into question is specifically the idea that hop oils themselves are somehow fleeting and highly volatile. It just doesn't add up for me.

[erockrph]

Would be interesting if you tasted the same two beers two months from now to text shelf life. I have found dry hop beers to be extraordinary within the first 4-6 weeks and then quickly fall off while hoppy beers with flame out additions only, while they do drop off significantly in hop flavor and aroma but remain cleaner and more drinkable and don't pick up the oxidized hop flavors like dry hop beers do.

I just started listening to the most recent BeerSmith podcast on my way to work this morning. Charlie Bamforth just dropped some random, interesting info that made me think of this. They have discovered that manganese can be a significant source of oxidation in beer, and that dry hopped beers are among the highest in manganese.

Charlie said they're just starting to look into this, and hat further research is needed todetermine how much of an effect the manganese would have. But listening to this set off all kinds of light bulbs in my head. It would seem to connect the dots pretty well here, if the actual act of dry hopping is boosting hop character only to be its own downfall by increasing oxidation at the same time. Hopefully more research is done on this and the results become available to the homebew community. I'm quite interested to see how this plays out.

[hopfenundmalz]

Would be interesting if you tasted the same two beers two months from now to text shelf life. I have found dry hop beers to be extraordinary within the first 4-6 weeks and then quickly fall off while hoppy beers with flame out additions only, while they do drop off significantly in hop flavor and aroma but remain cleaner and more drinkable and don't pick up the oxidized hop flavors like dry hop beers do.

I just started listening to the most recent BeerSmith podcast on my way to work this morning. Charlie Bamforth just dropped some random, interesting info that made me think of this. They have discovered that manganese can be a significant source of oxidation in beer, and that dry hopped beers are among the highest in manganese.

Charlie said they're just starting to look into this, and hat further research is needed todetermine how much of an effect the manganese would have. But listening to this set off all kinds of light bulbs in my head. It would seem to connect the dots pretty well here, if the actual act of dry hopping is boosting hop character only to be its own downfall by increasing oxidation at the same time. Hopefully more research is done on this and the results become available to the homebew community. I'm quite interested to see how this plays out.

Off to listen to Dr. Bamforth! Thanks.

[HoosierBrew]

Would be interesting if you tasted the same two beers two months from now to text shelf life. I have found dry hop beers to be extraordinary within the first 4-6 weeks and then quickly fall off while hoppy beers with flame out additions only, while they do drop off significantly in hop flavor and aroma but remain cleaner and more drinkable and don't pick up the oxidized hop flavors like dry hop beers do.

I just started listening to the most recent BeerSmith podcast on my way to work this morning. Charlie Bamforth just dropped some random, interesting info that made me think of this. They have discovered that manganese can be a significant source of oxidation in beer, and that dry hopped beers are among the highest in manganese.

Charlie said they're just starting to look into this, and hat further research is needed todetermine how much of an effect the manganese would have. But listening to this set off all kinds of light bulbs in my head. It would seem to connect the dots pretty well here, if the actual act of dry hopping is boosting hop character only to be its own downfall by increasing oxidation at the same time. Hopefully more research is done on this and the results become available to the homebew community. I'm quite interested to see how this plays out.

Off to listen to Dr. Bamforth! Thanks.

Yeah ,good info.

[charles1968]

Makes sense. My experience also is that dry hopped beers are great for the first 2-3 months and then go downhill more steeply than other beers, whereas hopstand beers are more stable over time, if less intense when young.