Attn Beer Chemists

[anday6]

Whirlpool hop alpha acid isomerization. Characterize the rate of alpha acid isomerization of near boiling wort and incorporate it into standard bittering equations.

Make Tasty proud.

[Ozwald]

Whirlpool hop alpha acid isomerization. Characterize the rate of alpha acid isomerization of near boiling wort and incorporate it into standard bittering equations.

Make Tasty proud.

Add first wort hopping & just write the paper on Tasty

[theobrew]

Whirlpool hop alpha acid isomerization. Characterize the rate of alpha acid isomerization of near boiling wort and incorporate it into standard bittering equations.

Make Tasty proud.

Add first wort hopping & just write the paper on Tasty

Dog hair and mash chemistry would be a good topic too!

[bernd]

Thanks for the replies! You've given me some good suggestions. I'm taking a few classes with perhaps a career change in mind, and organic chem just happens to be one of them. My background is in geochemistry, so I've mostly dealt with inorganics.

I think I have enough here to pick something. I'll update once I settle on something and the instructor has given me the OK.

[bernd]

I just wanted to update this thread since the paper has been written, and the class has been completed. I wrote about the light struck reaction where light exposed beer causes some of the alpha acids to split apart and turn into radicals. A radical then picks up a sulfur group making a thiol (compound with a Sulfur-Hygrogen group) which "skunks" the beer. Most of the information in the paper is either stuff you already all know, and/or chemical synthesis, so I'll spare you those details. I will share some things that I didn't know.

The light struck reaction is catalyzed by riboflavin. Part of the riboflavin molecule radicalizes upon exposure to UV and visible light, which in turn reacts with the alpha acid and ultimately goes on to create the thiol. Most researchers believe the sulfur comes from cysteine, an amino acid. Also, there are some (presumably large corporate) breweries out there using hydrogenated hop extracts to try and eliminate the problem. The theory being that there are fewer sites on the alpha acid molecule that can radicalize. However, a lot of researchers believe the light struck reaction is also heat driven as similar off-flavors develop in beers made with these extracts. Not so much a skunkyness occurs in these beers, but more of an onion flavor.

It was fun to write and research about this, and talk about homebrewing to a bunch of interested students. Thanks for help.

cheers,
bernd