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seen Apr 23 '12 at 14:05

All things beer flavor. If I don't know it yet, I want to.

BS and MS in Food Science and Technology

ASBC Technical Subcommittee on Sensory

Published, Journal of the American Society of Brewing Chemists

Hop chemistry focus


Feb
28
comment What is wet hopping and how does it differ from dry?
mdma: You're right about the solubility and lack of isomerization of alpha acids but apart from those, hop polyphenols and oxidized beta-acids can have bitter qualities and are imparted to the beer during dry-hopping.
Jan
23
comment Risk/Reward Question: Should you leave the lid off while chilling wort that is high in DMS?
You don't really "drive off" the SMM, you convert it to DMS and drive THAT off. And all of the research I've seen says that there is always an excess of SMM in the malt and that a 90min boil will never be able to diminish it. If you are not getting noticeable DMS in you final beers, then you seem to be doing fine chilling your wort in an timely manner.
Jan
23
comment Cold and Hot Break
It's not really the hop oils which are brought out by protein precipitation. It's the iso-alpha acids, which readily adhere to the flocculating protein break. Ergo, not much impact on hop aroma, more of an impact on hop bitterness.
Jan
18
comment Why would aeration cause diacetyl
I'm not sure what "super healthy yeast" means, for one thing. I've discussed this with other brewers, and they've said what you're implying: ideally there should be no alpha acetolactate in the beer. In our production facilities however, there apparently is because I've charted the increases in D during aging, but the yeast ferments fine otherwise. It may be a yeast strain issue as well, with some leaving more than others.
Jan
13
comment Salvaging flat beer?
Pediococcus and other LAB's prefer anaerobic environments.
Jan
13
comment Salvaging flat beer?
"The dry ice will melt and return to a gas" --- This process is not melting, it's sublimation.
Jan
12
comment How do I determine where the off-flavors of my brew are coming from?
Went through that list looking for inaccuracies. Only found one: "In beers which use pre-isomerized hop extract and very little flavoring hop additions, the beer will be fairly immune to damage from ultraviolet light." --- Uh, it's REDUCED hop extracts, not just pre-isomerized, that are resistent to photodegradation.
Nov
23
comment Thick head on Double IPA
It's not the polyphenols which promote foam formation/stability. When polyphenols interact with barley hordeins (proline-rich proteins) they form trub in the kettle and chill-haze in the package. When polyphenols interact with proline-rich proteins in the mouth, it creates astringency. These are weak interactions, not "binding". What promotes foam formation and stability is proteins (MW > 5000), gums like b-glucan and arabinoxylan, metal ions, and iso-alpha acids. In this beer, it's likely due to more protein (high gravity) and more iso's (more hops).
Nov
22
comment Dry malting - a crazy idea?
You kind of have it backwards. Malt already has the long chains of molecules (called starch, unfermentable) and the temperature of the mash dictates how those starches break down into fermentable sugars. It's not so much the length of these sugars that determine their fermentability, but the types of bonds between them. The left over sugars that are unfermentable have bonds that the enzymes can not break. But these left over molecules do not impart aroma, only sweetness and mouthfeel.
Nov
22
comment Old homegrown hops
Yeah, you're right, I should have used "efficiency" rather than "utilization". Correcting the post now.
Nov
21
comment Will Dry Hopping Add Bitterness?
Thanks for that. The whole part up to the parenthesis is bogus.
Nov
15
comment Will Dry Hopping Add Bitterness?
That is correct, although not many alpha acids will be extracted into a cool aqueous product. They are very hydrophobic, so they don't like to be in water. As I said, most bitterness resulting from dry-hopping comes from polyphenols.