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  • For humans, food and drink are more than just a necessity for survival.

  • They're a huge part of our culture and our history, shaping our lives on a daily basis.

  • And alcohol has had perhaps the strongest, uh, influence on us.

  • Pun intended.

  • From soft alcohols like beers and wines to hard liquors like whiskey and vodka, booze

  • comes in many shapes and styles, and can be found all over the world.

  • But how did humans discover alcohol, and how is it made?

  • Thanks to some microscopic organisms, some time, and some crafty chemistry, we've gotten

  • pretty good at our creating our own hooch!

  • The alcohol we're describing today is ethanol, which is actually just one type of alcohol.

  • But it's the only one that's safe to drink in large quantities, because we've developed

  • the ability to metabolize, or break down and eliminate its toxic components.

  • Ethanol occurs in nature thanks to fermentation -- the process of breaking sugars down into

  • ethanol and carbon dioxide.

  • And humans -- and our non-human ancestors -- have been able to metabolize that ethanol

  • for a really long time.

  • From examining our DNA, some scientists estimate that our ancestors developed the ability to

  • metabolize ethanol around 10 million years ago -- way before we were mixing our own cocktails.

  • Back then, we hadn't even split off from the ancestors of chimpanzees.

  • But that adaptation could have been helpful for our early primate ancestors by allowing

  • them to eat fermented fruit without getting sick.

  • Evolving humans must have enjoyed what they felt when they ate fermented fruits, because

  • figuring out how to create our own fermented beverages quickly became a centerpiece of

  • human culture.

  • In fact, there are some researchers who believe that our desire for alcohol is what drove

  • us to develop agriculture, which would have given us constant access to the grains and

  • starches needed to produce our own booze.

  • The earliest known evidence of the deliberate creation of an alcoholic beverage is 9,000

  • years old, discovered in some pottery in the Yellow River Valley in China.

  • This drink was some sort of wine, and contained rice, honey, and grapes.

  • In 2005, researchers actually recreated the drink based on a chemical analysis, and apparently

  • it tasted, quote, “very intriguing.”

  • Archaeologists think that around the same time people were originally making this stuff,

  • barley beers and grape wines were being produced in the Middle East.

  • People probably made those early drinks by leaving fruits and grains in covered containers

  • for long periods of time.

  • Eventually, they'd open the containers, and the liquid inside would be alcoholic -- but

  • for thousands of years, no one knew exactly why this was happening.

  • Thanks to modern science, we've got it pretty much figured out.

  • Beers are produced by fermentation, which comes from the Latin fervere, meaningto boil.”

  • Which makes sense, because the mixture of grains and water does bubble during the process.

  • And a beer really only needs four basic components: grain, water, yeast, and hops.

  • Different varieties of these components mixed in different ratios can give each beer a distinct flavor.

  • There are also different ways to do the beer-brewing itself.

  • But here's how the process generally works:

  • The first step in making beer involves cooking grains in water, which produces a mix called

  • the mash.

  • The heat activates enzymes within the grains and begins to break the starches down into

  • simple sugars.

  • Different grains are used for different kinds of beer; dark roasted grains are used for

  • darker, heavier beers like stouts while light grains are used for light beers, like wits

  • and pilsners.

  • Once they've all been cooked down, the grains are removed from the pot and the remaining

  • liquid is boiled.

  • At this point, the liquid is called the wort, and it's during this step that the primary

  • flavoring element of the beer is added -- hops.

  • Hops are actually flowers, harvested from a climbing vine called Humulus lupulus.

  • Beers have always been flavored with herbal mixtures, and we're not sure when or why

  • hops became the herb of choice -- but it was first noted as being part of brewing sometime

  • in the ninth century CE.

  • Adding hops to beer helped balance the sweet flavors from the grains with an acidic kick,

  • but more importantly, the hops kept it from spoiling, so the beer lasted longer.

  • We now know that hops produce antibacterial compounds called alpha and beta acids, which

  • help keep the beer free of bacteria and support the growth and survival of the yeast.

  • These acids mainly give the beer its distinctive bitterness, but different varieties of hops

  • can also give beers citrusy, floral, and even piney notes.

  • After the boil, the liquid is rapidly cooled to prevent bacterial contamination and oxidation,

  • which can change the taste of the beer.

  • Once the wort is cooled, the yeast is added to begin the fermentation process.

  • Yeast -- in this case, a particular variety called Saccharomyces cerevisiae -- is a microscopic,

  • single-celled fungus.

  • Yeast rely on sugars for energy, so they eat up the sugars in the wort and spit out carbon

  • dioxide and ethanol as waste products.

  • The carbon dioxide is why the liquid bubbles, and the ethanol is why there's alcohol in beer.

  • During the first phase -- the primary fermentation -- there's a lot of yeast hard at work.

  • All that waste carbon dioxide is allowed to escape the container, while the ethanol is

  • left behind.

  • After a while -- usually a minimum of two weeks -- most of the sugar has been consumed

  • and most of the yeast is dead.

  • In some cases, the beer is transferred to bottles with a small amount of sugar, to help

  • fuel the remaining yeast through the last step: secondary fermentation.

  • The beer is then tightly capped, and the carbon dioxide and ethanol produced within the container

  • are preserved, finally turning the liquid inside into the fizzy, intoxicating beverage

  • so many of us love.

  • Wine production is similar to beer-making in a lot of ways.

  • It's just that, instead of grains, wines use fruit to produce alcohol.

  • And as you probably know if you've ever tasted a $3 bottle of wine, different varieties

  • of grapes, and how they're prepared, can dramatically affect the flavor of the wine.

  • First, the grapes are crushed. Back in the day, people used to stomp on the grapes in

  • big tubs, but now it's generally done with specialized mechanical crushers.

  • The resulting mixture of skins, pulp, and juices is called the must.

  • Whether the wine is a red or a white usually depends on this step.

  • White wines are often made from green grapes, and red wines are generally made from purple

  • grapes -- but the color of the grape doesn't automatically determine what type of wine

  • it will be.

  • In fact, purple grapes can be used to produce both kinds of wine.

  • Leaving the dark grape skins sitting in the must will lead to a red wine, while separating

  • the juices from the skins and pulp quickly will lead to a white wine.

  • Those dark grape skins also contain tannins -- compounds that a chemist would call polyphenols.

  • They're made of lots of connected rings of carbons attached to an oxygen and a hydrogen.

  • These compounds give red wine its characteristic dryness, and help red wines age well, smoothing

  • and mellowing the flavor over time.

  • As with beer, the key component in turning the grapes into wine is the presence of yeast.

  • In the old days, naturally-occurring wild yeast on the grapes, mashed into the must

  • by winemakers' feet, would kickstart the process.

  • These days, winemakers sterilize the must and add their own specially-selected yeast

  • for better control over the wine's flavor.

  • Just like with beer, the yeast converts the grape's sugars into ethanol and carbon dioxide.

  • After fermentation, the yeast is killed off or filtered out and the liquid is clarified

  • to remove particles that might affect the taste or appearance of the wine.

  • The wine may then be aged in wooden barrels for a few months to a few years, which gives

  • the drink more flavors.

  • Finally, it's bottled and shipped off for consumption, ready to be sipped by vinophiles everywhere.

  • So those soft alcohols, as it turns out, are pretty easy to make by mistake - but what

  • if you want throw a really crazy party?

  • How do we make hard liquor?

  • High-alcohol-content beverages like vodka and whiskey require an additional step: distillation.

  • Distillation is a process of deliberate evaporation, cooling, and condensation that produces purified liquids.

  • Creating hard liquors this way takes advantage of the fact that ethanol has a lower boiling

  • point than water, so i t turns into a gas at a lower temperature than water does.

  • Just like with beer and wine, hard liquors begin with a fermentation step.

  • Different fruits, grains, and starches can be used to create this initial brew, depending

  • on the liquor.

  • For example, potatoes are generally used for vodka, while bourbon is made from corn, rum

  • comes from sugar cane, and tequila is made from agave.

  • The yeast gobbles up all of those sugars and produces ethanol and carbon dioxide, but the

  • liquid has a relatively low alcohol content -- around 10-15%.

  • So, to make the liquor truly hard, we have to purify some of that liquid to give it a

  • higher alcohol content.

  • The liquid is transferred to the still, where it's heated inside the pot until the components

  • with lower boiling points begin to boil off.

  • As the solution vaporizes, the temperature is increased very slowly, pushing other compounds

  • to boil at the appropriate temperatures.

  • The boiled--off vapor rises to the top of the pot and passes into the distillation column,

  • where specialized plates cool the vapor and cause it to condense and drop back into the pot.

  • This gives distillers precise control over the spirits as they pass up through the column,

  • allowing them to make adjustments to the contents and flavor of the drink.

  • The compounds with the lowest boiling point are able reach the top of the column and pass

  • into the lyne arm, a horizontal pipe that condenses the vapor back into liquid so it

  • can be collected.

  • This distillate is collected in stages, with each stage kept separated by its boiling points.

  • The first portion of the distillate, called the heads, contains the most volatile compounds

  • - the liquids with the lowest boiling point.

  • These include acetone and esters, and small amounts of these compounds are saved to add

  • flavor to the final product.

  • The second portion of the distillate is called the heart, and it's the most important part,

  • because it contains all of that intoxicating ethanol.

  • The heart is collected, mixed with some of the heads, and usually further modified until

  • it reaches the desired flavor profile.

  • Whichsounds really strange out of context.

  • Some of these modifications involve flavoring the liquid directly, like by adding juniper

  • berries to gin.

  • They can also involve redistillation -- passing the distillate through the process all over again.

  • And of course, hard liquors can be modified through aging.

  • Like wine, the type of container a spirit is aged in can have a significant effect on

  • its behavior.

  • Bourbon is aged in newly cut and freshly-charred oak barrels, imparting a rich, smoky flavor

  • to the drink.

  • Scotch, on the other hand, is aged in used barrels -- usually in barrels that have been

  • previously used for aging bourbon or sherry.

  • Different varieties of the same kind of spirit can age for different amounts of time, too

  • - like how white, or blanco tequila isn't aged, but reposado, or rested tequilas have