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| Earth on Aug 17, 2011

Lifeform of the week: Agave, from booze to biofuel

Sobriety? Energy crises? Whatever the problem, agave can lend a prickly hand.

About a decade ago things went terribly awry with the delicate supply/demand ratio of blue agave, and New York City – where I was living at the time – was hit with a tequila shortage at the onset of summer, aka margarita season.* Faced with rising cocktail ingredient prices, creative restaurant owners scrambled to save outdoor patio happy hours with novelty margaritas made using such spirits as rum (nice try, but that’s called a daiquiri) and vodka (just plain wrong). But the quasi-ritas were a bust and summer was ruined. RUINED, I tell you.

Image Credit: Chad Miller.

If that story alone doesn’t impress upon you the value of a genus of plants known as agave, let me add that they can also be turned into sweeteners, textiles and decorations for parched desert lawns (no watering needed, as they are succulents). And now scientists are exploring their ability to provide a suitable fuel alternative to oil. Surely you can drink to that.

Life and death

When agaves bloom, they bloom big. Image credit: Rael B.

The agave plant lives a life of dutiful sacrifice. For years it toils away as a stocky cluster of leaves, saving nourishment for its offspring. Once sufficient resources have been amassed, an obscenely long flowering stalk springs from the agave’s core. This scrimping and saving stage of growth takes considerable time. The species Agave americana is nicknamed “century plant” for this tendency, which is a bit of hyperbole as it generally flowers after somewhere between 10 and 30 years of growth. But when the agave’s stalk emerges, it grows at breakneck speed – up to a foot in a single day. Total stalk height can exceed 20 feet. It’s a proud day for the plant, but after that it’s all over. Agaves die after flowering is complete, although they can produce shoots as they grow that live on after the original plant retires.

Margarita-ville

In harvesting a piña, leaves are discarded and only the center is used. Image Credit: Josh Larios.

Tequila is the best-known agave-derived product. It is made from the Agave tequilana species, specifically from the juicy heart of the plant, called the “piña” (“pineapple”). The juice is extracted and distilled into the tasty alcoholic beverage we’ve come to rely upon to salvage otherwise mediocre Tex-Mex food. It takes about 10 years for plants to mature enough to be harvested for booze-making (though more modern farming practices may cut this down to around 6 years), which is how the dreaded tequila shortage occurs. The time of planting is so far from the actual harvesting that it’s anyone’s guess how much tequila the world will want by then.

Pile of pretty piñas. Image Credit: Roman Gomez.

Bonus booze

Tequila isn’t the only alcoholic beverage bestowed upon society by gracious agaves. Mezcal, distilled from Agave americana, is gaining the attention of fashionable spirits connoisseurs as an alternative to tequila.† The New York Times wrote about the stuff back in 2009, so if you haven’t tried it by the end of this summer, you’re probably hopelessly gauche.

Got pulque? Image credit: Claire L. Evans.

And then there’s pulque – a milky beverage made from fermenting (rather than distilling) agave that dates back to the Aztec empire but is apparently sold in cans and bottles today (though its popularity is dwarfed by harder agave-derived liquors and boring old beer). Why have I never encountered this product in my neighborhood Mexican supermarket?

Other household products

Wait, there’s even more. If you forgo fermentation and distillation, the juice from agave piñas can be transformed into a sweet syrup, sold as agave nectar. It’s an increasingly popular alternative to sugar and honey, though there is some debate over its relative healthiness. While agave nectar has a lower glycemic index than ordinary table sugar, it makes up the difference with additional fructose, thus drawing comparisons to the most detested of sweeteners – high fructose corn syrup.

Another productive member of the agave clan, Agave sisalana, offers up a fiber – sisal – that can be made into rope and, more importantly, dartboards! Think about that next time you’re drinking tequila while playing darts.

Around the world and in your own backyard

Kooky-stemmed Agave attenuata. Image Credit: Royal Botanic Gardens, Sydney.

While perhaps less practical than drinks and darts, agaves also make for excellent ornamental yard plants. Given the huge volume of water wasted on irrigating turf grass in arid climates (which seems to be about half of the U.S. lately), there’s much to be said for a plant that looks good and needs almost zero water. Due to its lack of sharp prickles, Agave attenuata is a popular species for brightening up lawns without injuring children and pets. It also produces an amusing curved stalk when it’s time to flower.

Agaves are native to the warmer regions of the Americas, but their awesomeness has resulted in cultivation around the globe. Europe has been adorning itself with agaves for centuries, and sisal farming fared well in Africa before being largely outpaced by plastics. And places such as Australia are currently conducting trials of the newest, and perhaps most interesting use for agave – biofuel …

Biofuel – the other ethanol

As we’re all aware, society has some major fossil fuel issues. Transportation accounts for about 60% of global oil use and car ownership is on the rise. Biofuels, such as ethanol, have been proposed as an option for powering all these vehicles without relying on oil, but this idea is problematic too. Currently the main sources of ethanol are corn and sugarcane, food crops that grow on arable land. This means we have to trade food for fuel, which is a bad idea for a rapidly increasing global population. But agaves can make ethanol too (they’re already sort of doing it in the form of alcoholic beverages) and they can do it on un-farmable desert land without the degree of environmentally damaging irrigation and fertilization needed for crops like corn.

Image Credit: Josh Larios3.

A study published online on July 28, 2011 in the journal Energy & Environmental Science examined the potential environmental impact of agave-derived ethanol versus existing ethanols like corn and sugarcane. While agaves fared slightly worse than sugarcane, they pretty much mopped the floor with corn in terms of CO2 emissions during production relative to energy output.‡

But don’t buy that second car just yet. The authors warn that biofuels alone can’t solve the world’s energy problems. If everyone on earth starts driving as much as the average American, agaves won’t be able to save us. And keep in mind that the study only addresses the production end of biofuels. Ethanol, like gasoline, still gets burned to power a car. Emission studies offer varying results, but even those suggesting that burning ethanol instead of gasoline considerably reduces CO2 emissions also state that it may increase emissions of other harmful chemicals, such as formaldehyde.§ If a genie grants you only one wish, you might consider asking for better public transportation instead of more biofuels.

* Other cities suffered from the shortage as well. However, as New Yorkers, we didn’t have time to care about their problems.

† Mezcal has been kicking around Mexico for ages, and cheaper forms of it gave birth to the tequila worm legend. In reality, the worm is just a moth larva that can find its way into substandard bottles of mezcal and has no hallucinogenic properties.

‡ Sugarcane ethanol’s success is mostly limited to Brazil’s climate, which maximizes efficiency for this crop but is tricky to replicate in drier climates.

§ More specific numbers and chemical names can be found here.

More Lifeforms from Alex Reshanov:

Portuguese Man o’ War, a crew of four

Naked mole-rat genome exposed

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Horseshoe crabs have something for everyone

For all lifeforms