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Páginas: 5 (1132 palabras)
Publicado: 14 de abril de 2011
3/31/2011
ACS Webinars™
We will start momentarily at 2pm ET
Download slides: http://acswebinars.org/bamforth2011
Contact ACS Webinars™at acswebinars@acs.org
1
Help Shape the future of ACS Webinars!
Join the ACS Webinars Audience Advisory Panel! Learn more: www.acswebinars.org
Contact ACS Webinars™at acswebinars@acs.org
2
1
3/31/2011
Have Questions?
Use theQuestions Box!
Or tweet us using #acswebinars
Download slides: http://acswebinars.org/bamforth2011
Contact ACS Webinars™at acswebinars@acs.org
3
You could be the lucky winner!
One lucky winner will receive a signed, hardback copy of Charlie’s book, Beer is Proof God Loves Us: Reaching for the Soul of Beer and Brewing!
Contact ACS Webinars™at acswebinars@acs.org
4
2 3/31/2011
Do You Know a Hero of Chemistry? Nominate them now
At the 2011 ACS Fall National Meeting in Denver, we will be honoring Heroes of Chemistry for the vital role these industrial chemical scientists and their companies play in improving human welfare through successful commercial innovations and products. It presents an ideal opportunity to enhance the public image of the chemical andallied industries. Each year, Heroes of Chemistry are nominated by their own companies to recognize their talent, creativity, and innovation. More information can be found at www.acs.org/industry
American Chemical Society
5
Upcoming ACS Webinars™
www.acswebinars.org/events
Tuesday, April 5, 2011
Successfully Working with Recruiters – Dos and Don’ts
Patrick Ropella, Ropella, and DonAlexander, Carlyle & Conlan
Thursday, April 7, 2011
Optimizing the Workplace Across Five Generations of Scientists
Tamara Erickson, author and trainer on how to build an innovative organization
Contact ACS Webinars™at acswebinars@acs.org
6
3
3/31/2011
ACS WEBINARS™ March 31, 2011 Advanced Chemistry of Beer and Brewing
Charles Bamforth, UC Davis
Steve Carlo, Chemist,Homebrewer
Please submit your questions for the speaker via the Questions Panel in GoToWebinar
Download slides: http://acswebinars.org/bamforth2011
Contact ACS Webinars™at acswebinars@acs.org
7
Advanced Chemistry of Beer and Brewing
Charlie Bamforth
March 31 2011
4
3/31/2011
Quality of Beer Package Foam Gushing Clarity Color Flavor Stability Safety & wholesomeness Notmutually exclusive
Barley
malting
Malt
mashing boiling
Wort
fermentation
“Green Beer”
Beer
stabilization filtration
5
3/31/2011
Aspects of beer foam
Formation (nucleation, beading) Stability (head retention) Lacing (cling, adhesion) Texture, whiteness etc
6
3/31/2011
Drainage
Q= 2ρgqδ 3η where Q is flow rate η is viscosity of film liquid ρ is density q islength of Plateau border g is acceleration due to gravity δ is thickness of film
7
3/31/2011
Beer foam Physics
Disproportionation
Beer foam Physics
Disproportionation (continued) rt2 = ro2 - 4RTDS γ t Pθ where rt is the bubble radius at time t ro is bubble radius at the start R is the gas constant T is absolute temperature D is the gas diffusion coefficient S is the solubility ofthe gas γ is the surface tension P is atmospheric pressure θ is the film thickness between bubbles
8
3/31/2011
Foam
Positives polypeptide iso-α-acids Me 2+ N2 Negatives Lipid Detergents Ethanol
Which proteins?
-Discrete polypeptide hypothesis - Generalized amphipathic polypeptide hypothesis
9
3/31/2011
Some proposed foaming proteins Lipid Transfer Protein (LTP1) Frombarley Unchanged in malting and mashing Activated during boiling by denaturation
Protein Z (40kD protein) - from barley - attached to β-amylase
10
3/31/2011
Protein mixture Salt solution Octyl sepharose
Hydrophobic protein binds strongly
unbound water hydrophilic
glycol
→ increasingly hydrophobic
The generalized amphipathic polypeptide hypothesis
11
3/31/2011...
ACS Webinars™
We will start momentarily at 2pm ET
Download slides: http://acswebinars.org/bamforth2011
Contact ACS Webinars™at acswebinars@acs.org
1
Help Shape the future of ACS Webinars!
Join the ACS Webinars Audience Advisory Panel! Learn more: www.acswebinars.org
Contact ACS Webinars™at acswebinars@acs.org
2
1
3/31/2011
Have Questions?
Use theQuestions Box!
Or tweet us using #acswebinars
Download slides: http://acswebinars.org/bamforth2011
Contact ACS Webinars™at acswebinars@acs.org
3
You could be the lucky winner!
One lucky winner will receive a signed, hardback copy of Charlie’s book, Beer is Proof God Loves Us: Reaching for the Soul of Beer and Brewing!
Contact ACS Webinars™at acswebinars@acs.org
4
2 3/31/2011
Do You Know a Hero of Chemistry? Nominate them now
At the 2011 ACS Fall National Meeting in Denver, we will be honoring Heroes of Chemistry for the vital role these industrial chemical scientists and their companies play in improving human welfare through successful commercial innovations and products. It presents an ideal opportunity to enhance the public image of the chemical andallied industries. Each year, Heroes of Chemistry are nominated by their own companies to recognize their talent, creativity, and innovation. More information can be found at www.acs.org/industry
American Chemical Society
5
Upcoming ACS Webinars™
www.acswebinars.org/events
Tuesday, April 5, 2011
Successfully Working with Recruiters – Dos and Don’ts
Patrick Ropella, Ropella, and DonAlexander, Carlyle & Conlan
Thursday, April 7, 2011
Optimizing the Workplace Across Five Generations of Scientists
Tamara Erickson, author and trainer on how to build an innovative organization
Contact ACS Webinars™at acswebinars@acs.org
6
3
3/31/2011
ACS WEBINARS™ March 31, 2011 Advanced Chemistry of Beer and Brewing
Charles Bamforth, UC Davis
Steve Carlo, Chemist,Homebrewer
Please submit your questions for the speaker via the Questions Panel in GoToWebinar
Download slides: http://acswebinars.org/bamforth2011
Contact ACS Webinars™at acswebinars@acs.org
7
Advanced Chemistry of Beer and Brewing
Charlie Bamforth
March 31 2011
4
3/31/2011
Quality of Beer Package Foam Gushing Clarity Color Flavor Stability Safety & wholesomeness Notmutually exclusive
Barley
malting
Malt
mashing boiling
Wort
fermentation
“Green Beer”
Beer
stabilization filtration
5
3/31/2011
Aspects of beer foam
Formation (nucleation, beading) Stability (head retention) Lacing (cling, adhesion) Texture, whiteness etc
6
3/31/2011
Drainage
Q= 2ρgqδ 3η where Q is flow rate η is viscosity of film liquid ρ is density q islength of Plateau border g is acceleration due to gravity δ is thickness of film
7
3/31/2011
Beer foam Physics
Disproportionation
Beer foam Physics
Disproportionation (continued) rt2 = ro2 - 4RTDS γ t Pθ where rt is the bubble radius at time t ro is bubble radius at the start R is the gas constant T is absolute temperature D is the gas diffusion coefficient S is the solubility ofthe gas γ is the surface tension P is atmospheric pressure θ is the film thickness between bubbles
8
3/31/2011
Foam
Positives polypeptide iso-α-acids Me 2+ N2 Negatives Lipid Detergents Ethanol
Which proteins?
-Discrete polypeptide hypothesis - Generalized amphipathic polypeptide hypothesis
9
3/31/2011
Some proposed foaming proteins Lipid Transfer Protein (LTP1) Frombarley Unchanged in malting and mashing Activated during boiling by denaturation
Protein Z (40kD protein) - from barley - attached to β-amylase
10
3/31/2011
Protein mixture Salt solution Octyl sepharose
Hydrophobic protein binds strongly
unbound water hydrophilic
glycol
→ increasingly hydrophobic
The generalized amphipathic polypeptide hypothesis
11
3/31/2011...
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