beer chemistry

[BB2]

Does anyone know how to post on the janux forum just to the beerborg group? Seems like I can only use the group list for live chat.

Anyway I wanted to see if anyone else had found online textbook resources. I am referencing the foillowing, in addition to WATER and PRINCIPLES OF BREWING SCIENCE both of which I got for Christmas at a steal on Amazon. The online texts are available at http://www.saylor.org/ and http://openstaxcollege.org/textbooks/biology:
Introductory Chemistry.pdf
Chemistry Principles, Patterns, and Applications.pdf
The Basics of General, Organic and Biological Chemistry.pdf
Biology.pdf

I am finding this course challenging but not daunting so far. It will be worth it if we make better beer.

[Yankeedag]

Who is BB2 calling a pdf? Should anyone be offended?

*

Coffee is ready... never mind.

[gwcr]

The quiz for unit 1 seems to be really messed up. Lots of folks taking the course complaining about the answers not being correct finally got them to take another look at it. Wish I would have known they put a hold on it prior to spending the time taking it this morning...

[BB2]

We have to retake it if we took it before the errors were caught- still due friday also. I had three questions that were correct but marked as wrong.

[gwcr]

Just re-took it. Missed 2...

[Brewbirds]

UH OH, I'm making a pot roast for dinner and BB2 and I started talking about boil off rates, moisture content of various vegetables and aroma loss vs. heat retention on whether or not to leave the lid on.

It seems I need to sacrifice either carrot aroma or roast tenderness.

[philm00x]

Maybe you should have done a partial volume roast so that you can add water into the process to keep it all moist and still get good aroma!

[Brewbirds]

Maybe you should have done a partial volume roast so that you can add water into the process to keep it all moist and still get good aroma!

WOW you really are a wiseman! That is exactly what we decided I need to do to tweak the next batch. I had BB2 put it in the tasting notes.

[Wings_Fan_In_KC]

Holy Shite!!

I just watched the vids for unit 2 and I'm almost speechless. I think this course is going to be way over my head.

The distances between the residues and moieties in the ribbon dipiction are 2.7 to 2.8 angstroms?

Does your GABA - A receptor contain a delta subunit?

Are you f*cking kidding me?

[gwcr]

Right there with ya Wings...I was pretty solid on Unit 1, but this one definitely goes way down the chemistry rabbit hole. I'm trying to access areas of my brain that have long since been killed off by the youthful exuberance of my past (and not actually needing any of the chemistry info I learned 20+ years ago). Good thing this unit is about the health implications of alcohol...

[Brewbirds]

Holy Shite!!

I just watched the vids for unit 2 and I'm almost speechless. I think this course is going to be way over my head.

The distances between the residues and moieties in the ribbon dipiction are 2.7 to 2.8 angstroms?

Does your GABA - A receptor contain a delta subunit?

Are you f*cking kidding me?

I was just telling BB2 this morning not to be daunted. The chemistry of making beer boils down to breaking up all the big words into things you can pronounce.

[BB2]

UNIT TWO. I am posting this here because I am not quite sure I know how to post to our beerborg group on the Janus site, and as we have discovered the health effects material go be overly technically complicated. Hope this helps (please respond if anyone sees errors).

The attached diagram and footnote summarizes the metabolism of alcohol. When you drink about 10% of the ethanol goes right through the bloodstream and exits through breath and urine. The rest gets processed in the liver through the alcohol dehydrogenase system. Simply put the ethanol is transferred temporarily into acetaldehyde (a poison) and then quickly into acetate. Acetatee then breaks in to CO2 and H2O - so always exhale while pissing.

In more detail, the normal process in blue is a two way continuous oxidation-reduction process that helps limit the amount of poison while stages two and three work. Redox is just an exchange of ion charges and hydrogen ions back and forth. ADH is the enzyme that makes stage one work by borrowing a coenzyme from cells called NAD and, passing it a hydrogen ion and two electrons taken from the ethanol, creating NADH (the reduction). The exact reverse process creates ethanol from acetaldehyde if there's too much (oxidation). The second stage works pretty much the same to convert acetaldehyde to ACETATE (diagram incorrectly shows acetone - hey I didn't draw it), but uses a different enzyme ALDH (enzyme names show what compounds they work upon hence remember this one as AcetaLdehyde DeHydrogenase, and the other Alcohol DeHydrogenase - ok, made that up). \

So, all's well given low alcohol consumption but the backup MEOS system, microsomal ethanol oxidizing system in red, takes care of excess alcohol under conditions of heavy drinking. Another enzyme CYP2E1 gets formed as needed and it generates a second redox reaction delivering a hydrogen ion and two electrons to another coenzyme, NADP.

ethpathway1.jpg (26.32 KiB) Viewed 933 times

Figure 1: Metabolic pathways of alcohol. The main oxidizing enzyme is cytosolic alcohol dehydrogenase (ADH), which converts ethanol to acetaldehyde. Cytochrome P450 2E1 (CYP2E1), an enzyme of the microsomal ethanol oxidizing system (MEOS) that is inducible with chronic alcohol consumption also metabolizes alcohol. The conversion of acetaldehyde (a toxic metabolite) to acetate is by mitochondrial aldehyde dehydrogenase (ALDH). Both ADH and ALDH have polymorphisms that affect the rate at which acetaldehyde is generated and metabolized.

Mentions: Alcohol is detoxified and eliminated primarily in the liver via a series of oxidative metabolic reactions.10,11 The three major steps are: (1) reversible oxidation of ethanol to acetaldehyde, which is toxic; (2) non-reversible metabolism of the toxic acetaldehyde to acetate; and (3) breakdown of acetate to water and carbon dioxide (Fig. 1). The first step in alcohol oxidative metabolism is effectuated by key enzymes, including alcohol dehydrogenase (ALD), cytochrome P450 2E1 (CYP2E1), and catalase. ADH is the main oxidizing enzyme; it has a high affinity for alcohol12 and breaks down ethanol in the cytoplasm. CYP2E1 is utilized by a distinct pathway that is induced by chronic alcohol consumption, and results in acetaldehyde formation in peroxisomes. A third path of first-step ethanol metabolism is mediated by catalase oxidation of ethanol in microsomes.13,14

[Wings_Fan_In_KC]

Took the quiz this AM and only missed two. Solid "B" there at 83.3%.

Funny how a little studying improved my results.

I think I missed half of the first quiz becasue I didn't study the material at all, just watched the vids and jumped into it and then realized that it was "one and done".

[GOF]

I wonder if they'll have a course on the biology of brewing? I mean the yeast is a living organism, right?

[DaYooper]

Oh thats right it is test weekend again. Need to finish doing my studying....