Thursday, August 20, 2009

Fermentation: Break it DOWN

I love beer! I love beer so much I am on a committee for beer. But how many of you out there know about the chemistry behind making beer? I mean the itty-bitty, teeny-weenie changes that take place on a molecular level. To know about fermentation, you need to know something about oxidation and reduction. To know about oxidation and reduction, you have to know how electrons move between reducers and oxidizers. It’s like a Russian Doll, you see. One thing fits inside a smaller one, then a smaller one, then smaller, until you get down to the teeeeeeny tiny world of the electron. Really, fermentation (thus beer brewing) is about how electrons move around.

Think of oxidation/reduction this way: You’re at a cocktail party. You’re having a good time, drinkin’ drinks, chatty chatty when THAT couple walks in. You all know the couple I’m talking about. The couple who live to shuffle their emotional baggage between one other. Collective sigh. Don’t make eye contact. Uh oh. Here they come to talk to you. For the purposes of this analogy, one partner will play Iron (Fe), the other will be Copper (Cu), and their emotional baggage is Sulfate (SO4). Sulfate has a molecular charge of negative 2, meaning it has two extra electrons.

Copper: Blah, blah, blah, oh yeah? Well at least your oxidizer helps you in the kitchen. Mine thinks I’m a maid.

Iron: Ha! HA! Let me ask you, Copper, who has been paying your car insurance for the last 6 months?

Copper: I’ve been looking on Craigslist to find a job for a YEAR! Cut me some slack.

Iron: *scoff* And you’ve been on 2 interviews in the last 3 months. What do you do all day when I’m at work?

Copper: I do lots of things!

Iron: Like what? You wake up at 11.

Copper: Seriously, fuck you. I didn’t even want to come to this party. These are all your friends.

Iron: You know what? We’re not doing this here. Not now…

(Both exit in sulky huff)

Aaaand scene. What a bummer, these two are. What you’ve just been privy to is the oxidation/reduction reaction which is written symbolically as:

Fe + CuSO4 --> FeSO4 + Cu

Copper starts off connected to Sulfate, the negative baggage. Iron actually WANTS that baggage because Iron (and Iron will never admit this if you ask it) actually derives satisfaction from taking Copper’s sulfate. The exchange reduces Copper and oxidizes Iron.

Copper is now in a reduced state because it has a less positive charge. This is only one example of oxidation and reduction. These types of reactions happen ALL the time in nature. This is what takes place in the process of fermentation to make beer. Not with Iron and Copper because then you would be poisoned and die, but you get the gist. Little yeast oxidize organic material and in turn give off carbon dioxide and alcohol to get you buzzed. Now if you’ll excuse me, I must get back to being chemically awesome! Toodle-ooo.