In 2000, food science researchers  found something surprising about a   part of our diet so basic, we don’t  even really think of it as a thing.

They fed a group of people 450  calories in jellybeans – best   experiment ever – while they gave the  other group a drink with 450 calories.

And the group that ate solid food  responded pretty much how you’d expect:   they felt full.

They even reduced their eating  for the rest of the day by about 450 calories.

But the group that drank their calories…didn’t.

They went on eating as normal –  and some even ate more than usual.

Scientists ran similar experiments again and   again – and they repeatedly found the  same thing: drinks don’t make us full.

Now, researchers aren’t 100% sure why.

It might  be that liquids enter our intestines faster than   food.

Or that beverages don’t trigger that “I’m  full!” peptides that we get from certain foods.

But either way, it turns out, our  bodies haven’t quite mastered drinking.

And that’s because of our past.

For almost all of human history,   as adults, we drank just one thing: water.

While beverages – from coffee to cocktails  – are basic in many cultures today,   humans only entered our “modern  beverage era” relatively recently.

Yep, that’s actually what scientists call it.

And our bodies just haven't caught up yet.

So when, exactly, did we start drinking  other things?

And why?

To find out,   we have to look at the world’s oldest  beverages – which might not be what you expect.

Okay, before we dive in, a reminder that  this is all based on what’s been written   or preserved in the archaeological  record and uncovered by scientists.

So it likely has some biases based on where  archaeologists have focused their work.

And some intriguing finds emerging  recently in places far from the general   Western-science-focused regions remind us that  there’s probably still a lot more to learn.

Now, if you had to guess  what the oldest beverage is,   you might speculate that it’s  something like fruit juice.

For the most part, though, it seems like ancient   humans didn’t bother turning fruits  into juice.

They just… ate the fruit.

Plant-based drinks are pretty old, though.

For example, modern coffee made from roasted  beans first appeared about 600 years ago,   probably in part of what was then  Yemen, but is now Saudi Arabia.

These coffee drinkers prized it for helping  them stay alert during religious ceremonies.

Drinks made of sweetened  lemon juice are even older,   potentially dating back to  over 1000 years ago, in Cairo.

And tea jumps back further  in the beverage timeline,   first popping up in Chinese  legends about 4,700 years ago.

But tea isn’t our oldest beverage.

And wine isn’t either, even though   it dates back to around 8,000 years ago  in Georgia – the country, not the state.

There are still two drinks that date back even  further, and are in competition for marking   the beginning of the modern beverage era.

And  they are incredibly different from each other.

A big piece of evidence for  one of these beverages is a   clay tablet from Mesopotamia, in what’s now Iraq.

It dates back to 6,000 years ago  and tracks the size of cow herds.

These ancient records likely indicate that these   people – the Sumerian civilization  – kept animals to produce dairy.

So, was our oldest beverage a glass of milk?

In 2019, researchers at London’s Natural History   Museum confirmed that drinking animal  milk is definitely at least that old.

To prove it, they checked with these  ancient milk drinkers themselves.

And while they couldn’t ask them directly, they  could scrape plaque from the teeth of skeletons,   some dating to nearly 6,000  years ago from across Britain.

It was too late to help with their dental hygiene,   but it did reveal what they drank.

Within  the plaque, scientists found milk proteins.

Back then, milk would have  solved several problems.

It’s rich in vitamin D, which makes it good for   people who struggle to produce enough  in less-sunny climates like Britain.

And it also contains vitamin C,   which is useful in places where fresh  fruits are rare, like central Asia.

Researchers even believe the consumption of this   beverage might have extended the  lifespans of Neolithic people.

So, is milk our oldest beverage,  then?

Well, maybe, maybe not.

There’s actually another surprising drink  that seems to appear around the same time.

And while milk is a practical drink, the  other beverage is… kind of the opposite.

Back in Sumerian society, archaeologists  have found pictographs showing oddly shaped   pots with narrow necks and sharp-pointed bottoms.

Dating to over 5,000 years ago, these images seem  to illustrate ancient breweries for making beer.

Other Sumerian texts show they  had something like 19 different   beers – more than enough to start a brew pub.

In fact, beer seems to have been  so popular that some researchers   estimate 40% of Mesopotamian  grain may have gone to brewing.

Other ancient texts reveal  that some Sumerian workers   even got paid in beer, up to five liters per day.

But why beer?

Well, beer purifies drinking water, and also  has its fair share of minerals and B vitamins.

But beer’s main appeal seems  to have been its effect.

Beer drinkers likely valued the beverage  for the intoxicating experience.

One ancient Egyptian scroll from 3,400 years  ago, for example, basically cautioned people   that after drinking beer, “You might say  things you won’t remember afterwards.” So, we know the Sumerians enjoyed both milk  and beer.

But what about everybody else?

It turns out, there’s one place that’s great  for tracking down humanity’s earliest beverage,   a place with a well-preserved  drinking culture: China.

On the Chan River in northern  China, archaeologists have found   two underground rooms that are  probably around 5,000 years old.

And inside, they found a stash of pots,   stoves, and stone funnels– all  things you’d use to brew beer.

A closer look confirmed that these chambers  are ancient breweries.

On the funnels,   archaeologists found grains  – probably millet and barley.

They also found… gunk.

And once they scraped it  off, vaporized it, and scanned the cloud of ions,   they discovered it was calcium oxalate, a  sediment that settles out of beer as it ferments.

But that’s not China’s oldest  beer.

Even older beverages pop   up in an unexpected place: tombs of the dead.

Toasting dead relatives at the graveside  was common in some parts of China,   and families often buried the  drinking glasses with the bodies.

And by 5,500 years ago, a striking feature  appeared in this graveyard pottery: legs.

Researchers think that these might have acted  like a tripod to heat alcohol over a fire,   warming it for graveside toasts.

But going back even farther – between  9,000 and 7,500 years ago – there’s   another big change in graveyard  pottery: pots with pinched necks.

These thinner necks would have  made it easy to seal a container,   which is something you might  do to ferment drinks like beer.

And in 2019, archeologists confirmed  that these were probably early beer vats.

By analyzing the residue from the  pots, they found evidence of starches,   fungi, and fermentation-related gelatin.

They also detected flavorings  like ginger and snake gourd root.

So, does 9,000-year-old beer mark  the start of the modern beverage era?

While evidence from ancient pottery says yes,  what about drinks from before there were pots?

In European history, there’s a whole  period known as the Pre-Pottery Neolithic,   lasting from about 12,000 to 8,500 years ago.

And some of the world’s leading beverage  archaeologists have long suspected that,   during this period, people drank milk.

And one of the leaders of this “old  milk” movement was Jean-Denis Vigne   at France’s National Museum of Natural History.

But Vigne’s ideas clashed with a major  archaeological concept called The   Secondary Products Revolution.

This theory, which appeared in the early 1980s,  states that secondary animal products like   milk – as opposed to primary products like meat  – couldn’t be as old as China’s graveyard beer.

Because, the theory stated,  these early human societies   supposedly weren’t organized enough  to keep animal herds for milking.

But other ‘old milk’ researchers  kept finding piles of goat and sheep   bones – the remains of herds they strongly  suspected ancient peoples kept for milk.

The problem was these were not associated  with any pottery to check for milk residue.

So, Vigne and his team looked  at modern ranching techniques,   which suggested that another way to spot ancient  milk could be by looking at the animals’ ages.

See, herds kept for milking  often contain older animals.

Because with meat herds, ranchers  usually slaughter as soon as   animals reach full size.

But milking  animals can be productive much longer.

So the team linked these  animals’ ages with tooth size,   comparing the teeth of modern animals to  the skeletons at archaeological sites.

And several bone piles contained  groups of older animals,   which suggested they could be  the remains of milking herds.

The oldest known sites they found with  milking-age animals were in Turkey, Syria,   and Iraq – and some dated  to over 10,000 years old.

While this pushed back the  beverage timeline even further,   putting milk in the lead for the  oldest beverage, the debate continues.

A 2001 analysis of a human skeleton from  Iran that was 11,000 years old showed signs   of the disease brucellosis, which usually  comes from exposure to unpasteurized dairy.

But in 2018, an archeological team found possible   beer residue in a cave settlement  in Israel that’s 13,000 years old.

And while the increasingly older archaeological  discoveries may lead us to think the debate may   never be settled, perhaps the oldest beverage  evidence actually comes from our own bodies.

Researchers have recently been  examining the genes that allow   adult humans to produce lactase –  the enzyme that breaks down milk.

And they found that a series  of genetic adaptations that   led to wide-spread milk-drinking  might be as old as 20,000 years.

But even if our beverage era  does reach that far back,   it’s worth remembering that this  timeline is incredibly recent.

Our species, Homo sapiens,  has been around for nearly   300,000 years – and for almost that  entire history, we only drank water.

Although researchers are still  uncovering the details of where,   when, and why our modern beverage era began,  the two oldest drinks provide some clues.

The nutrition acquired from milk reflects  how humans valued vitamins and ready energy.

Meanwhile, the old beer could reveal a different  side to ancient humans – a more social one.

So just maybe, these two oldest beverage  contenders show us two sides of ourselves:   the practical side and the not-so-practical side.

Either way, the next time you reach for a drink,   it’s worth remembering just how recent  this delicious practice really is.