Fermentation: A Depraved Gift from Nature

September 29, 2015, by , Posted in Blog,Education, 0 Comment

Fermentation: A Depraved Gift from Nature

When you think about it, drinking booze is kind of weird and gross.

First of all, an arguably rational species (us) will seek out – often at great expense and risk of self-harm – a substance that is toxic to them. That’s the weird part.

The gross part is that the toxic substance – ethyl alcohol– is excreted as waste by little critters that we can’t even see. Those critters – yeast, a type of fungus – are pretty bizarre themselves, from an anthropocentric point of view. These guys can live in a state of suspended animation for months or years, but somehow wake up when they get a whiff of sugar.

Neither little kids at a fructose-fueled birthday party nor frat boys have anything on yeast. The yeast usually begin with an orgy of instant reproduction, then proceed to gorge themselves on sugar, spray alcohol all over the place, and die once they’ve consumed all the snacks.  These gatherings are huge – as many as 100 billion single-celled yeast organisms may inhabit one liter of actively fermenting liquid.

You may remember the process of fermentation from high school biology described as yeast converting sugar into ethyl alcohol (also called ethanol), carbon dioxide, and heat. In reality, that’s an oversimplification, since not all yeast is created equal, and different species and subpopulations of yeast will produce very different types and amounts of other (non-ethanol) compounds called “congeners.”

Congeners are what makes booze interesting. Ethyl alcohol is ethyl alcohol: in moderate quantities it makes most people feel good, but that’s about as far as it goes. Congeners are responsible for the aromas and flavors that dazzle the palate and/or provide a socially acceptable pretext for a good buzz.

In the fermentation of cooked agave, congeners include compounds like fatty acids, esters, sulfur compounds, aldehydes, and other alcohols. When concentrated (via distillation), compounds like these can create pleasant aromas and flavors resembling spices, fruits, flowers, herbs and nuts.

So the next time you sip your favorite Tequila, mezcal, or any other adult beverage, take a moment to give thanks to our disgusting little comrades who give their lives so that we might imbibe. ¡Salud!

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