The Brewing Continues

Both fermenters are bubbling like crazy today; I don't have a rotameter hooked up, but I would guess that carbon dioxide production is peaking in excess of 100mL per minute.  Everything in the must is now suspended, buoyed by the bubbles rising from the yeast, which are now floating in a cloudy layer near the surface.

It's obvious enough that yeast produces a ton of carbon dioxide during anaerobic growth... but how?  Molecular oxygen is not present to act as the final electron acceptor in oxidative phosphorylation, so the TCA cycle (the source of the carbon dioxide produces by you right now) certainly isn't active.  For a closer look, we go to the basic (unbalanced) bioreaction stoichiometry:

C₆H₁₂O₆ (sugar) + CH_1.9O_0.51N_0.23 (protein) -> CH1_1.77O_0.49N_0.24 (biomass) + C₂H₆O (ethanol)

Most available protein is going to biomass (which has almost the exact same stoichiometric ratios as protein), along with some of the sugar.  Most of the sugar will go toward generating reducing equivalents (NADH) and energy carriers (ATP), in which it will be almost stoichiometrically converted to ethanol.  If you take a look at that stoichiometry:

C₆H₁₂O₆ (sugar) -> C₂H₆O (ethanol)

Glucose on the left has a 1:1 C:O ratio, whereas ethanol has a 2:1 C:O ratio.  Carbon dioxide has a 1:2 C:O ratio, so this is a likely solution for closing the mass balance!  Of course, this is all nasty global inference, which should be left to systems biology (fake science).

What really happens?  Pyruvate decarboxylase (using thiamine pyrophosphate [pictured] in an acid-catalyzed reaction) hacks pyruvate into acetaldehyde and carbon dioxide.  The acetaldehyde is converted into ethoxide by reaction with NADH, and is then protonated to yield ethanol.  This is 'Ethanolic Fermentation'.

(Isn't mechanistic biochemistry so much more satisfying?)

Let The Brewing Begin

Oh school - the more classes you've taken, the more doing well just comes down to going through the motions and taking the time.  Unfortunately, all of this fake learning has been keeping me from doing the stuff I really want to do.

I'm headed to Germany in two weeks, but I wanted to get one solid project going before I head out.  Fairly quick to set up with long wait times to product?  Brewing fits the bill perfectly.

I kind of feel like 'brewing' with store-bought malts is sort of a cop-out.  I'd rather go with something simple and straightforward, do it right (meaning without too much cheating), and expand upward as I get better at it.  There are many indications that mead was one of the first fermented beverages, even predating agriculture itself, so it seemed like the perfect place to start.

Setting everything up was very straightforward.
Follow this project's progress in my Brewing Notebook.

Environmentalism Extrema

I mentioned on Sunday that most environmentalists aren't calling for a reduction in the human population.  Some, however, are!  Others have messaged me saying they indirectly support human population reduction through better availability of contraceptive methods and education.  I've also heard the argument made that voluntary population control could help stabilize the economies of extremely depressed regions in Africa.  I guess it's worth keeping in mind that a reduction in per capita consumption only really has an effect if the population is fairly stable or declining.


The Voluntary Human Extinction Movement has a very interesting stance.  From their website:

"Phasing out the human race by voluntarily ceasing to breed will allow Earth’s biosphere to return to good health. Crowded conditions and resource shortages will improve as we become less dense."

Everyone likes to discuss 'carbon footprint', but perhaps 'carbon legacy' is just as important: if my six-person family severely limits its use of natural resources but still consumes more overall than a three-person family with a much higher per capita usage, who is 'more green'?

If I drive a Prius 30 miles to work every day and my coworker drives his old gas-guzzler but lives only 5 miles away, who is doing more to conserve?

Can you really claim to be an 'environmentalist' if you live in a climate where you need to heat your living space five months out of the year?

Should conservation be measured on a 'per-lighbulb' basis, or is it really only a relevant concept when it is considered in terms of all of the decisions an individual makes, including what they buy, what they eat, where they live and work... even how much they reproduce?

Discuss!

(thanks to Kyle for the link, Ben for the 'legacy' concept, and Mr. Somers for a really good point)

Environmentalist's Dilemma

The environmentalism movement has an image problem.

At first glance, it's difficult to see how this is possible.  Environmentalists, at the most basic level, are simply interested in finding and implementing steady-state solutions for humanity's mass and energy balances.  They want to protect the planet's natural biological diversity, and preserve natural environments and ecosystems for the enjoyment, use, and contemplation of future generations of our own species.

When many people think 'environmentalist', a number of images come to mind.  Let's take an analytical approach to analyze some of these images (so if you're not a Rational, stop reading here).

"Environmentalists think *insert endangered species* are more important than people"

Ecologically-speaking, humans are the top of the food chain, the highest of the high predators.  Granted, a lion could certainly do a number on you if you come across one, unarmed, in the savanna... but humans for the most part live in hives (cities, suburbs) where we kill and eat as we please.  Many high predators act as a check and balance on the population of the species they prey on (think foxes and rabbits); we have gone so far as to domesticate and raise our own prey, and when we do come in contact with wild populations that are tasty and easy to catch, we have a very long history of wiping them out completely.  We chop down forests and replace them with monocultured fields of turfgrass, corn and wheat; we destroy habitats that are overflowing with biological diversity, and only pidgins, rats, cockroaches, and housecats remain.  We have no stabilizing purpose in the biospheres we inhabit.

Take, for instance, the Pacific Yew (the original source of the anticancer agent Taxol), or pretty much any other native tree or plant: at the very bottom of the food chain, they provide food and shelter to countless other organisms.  From a biological perspective, plants are absolutely critical for regulating the global carbon redox balance (carbon dioxide vs. reduced carbon).  Humans, at the very top, serve no critical ecological functions.  If you were to wipe out a species of plant, or insect, or fungus, it would almost certainly cause major environmental destabilization; wipe out humans, and the result would be a net STABILIZING effect.

There are many, many humans - probably around seven billion at this point - and it would be next to impossible to wipe them all out.  Tigers, on the other hand?  ~2,000 in the wild.  (One tiger = 3.5 million humans?)

So, if you want to pick things apart rationally: humans ARE quite the invasive species, and global ecology would only really benefit from a reduction in their population.  This doesn't jive very well with the "god put us on this planet to kill, eat, and pillage whatever we want" mentality that the majority of Americans seem to embrace, so the source of anti-environmentalism animosity is not too hard to find.

The thing is, 99.99% of environmentalists are NOT advocating doing anything to reduce the human population (which would probably be the most straightforward, surefire solution...) - they're only saying that we need to reduce our per-capita rate of consumption of natural resources to limit the destabilizing effects that we have.

Disagree?  Open-fire below.

Tomorrow: "Environmentalists are against progress and technology"
This Week: "Environmentalists don't care about jobs or the economy"
Later: "Redox Balances, Global Warming, and The History of The World"
           "Environmentalism: what is it really protecting?"

Perfect Pasta

Getting pasta 'just right' takes patience and practice.

It helps to start with the best possible ingredients. White, tasteless, bleached-to-death pasta, a horrible holdover from the days of Wonder Bread and the 'faux-wood-and-gold' style, is no longer the only option: many companies are now offering whole-wheat and multigrain pastas that offer superior taste and nutrition.

White, Wheat, and 7-Grain pastas. Data from NutritionData.com and Ronzoni Healthy Harvest

While all products made from wheat flour will have the same glycemic index, whole grains include the bran component, which contains additional dietary fiber and B-vitamins.

Strangely, whole grain products tend to be more expensive than their bran-removed, bleached counterparts... I would think that whole grain products would involve fewer processing steps and therefore end up cheaper. It may be related to economies of scale - the typical American still prefers the bleached, tasteless stuff for a few cents cheaper per pound.