“Once you wake up and smell the coffee, it’s hard to go back to sleep” – Fran Drescher
“I orchestrate my mornings to the tune of coffee” – Harry Mahtar, pundit
“Ah, coffee. The sweet balm by which we shall accomplish today’s tasks.” – Holly Black, author
“Without my morning coffee, I’m just like a dried-up piece of goat.” – Johann Sebastian Bach

No one needs confirmation from “coffee quotes” or “good morning quotes,” or the ubiquitous coffee memes on Instagram and Twitter, to understand the value of that first cup of coffee in the morning. It may be the only thing – from New York to Nebraska, from Los Angeles to Louisiana – that unites us in today’s fractious world.

Regular coffee drinkers probably can’t understand how anyone could wake up until they’ve had their morning coffee, and it’s easy to see why. Statistics from the National Coffee Association (NCA) show that 62% of American adults drink coffee every day, and 90% of those coffee drinkers have their first cup with breakfast

Some have their own coffee grinder, a coffee or espresso machine, or a fancy French press at home. Others prefer to pick up an espresso, latte or iced coffee at Starbucks or their local coffee shop. (We shouldn’t leave out another popular option, instant coffee.)

Morning is obviously not the only time Americans (and countless others around the world) enjoy their coffee. The NCA statistics show that coffee drinkers’ average daily consumption is more than three cups per day; obviously, many rely on it for a quick pick-me up during the day.

But why is morning coffee so special?

One reason that coffee lovers crave that morning cup of joe: coffee smells so darned good. Ground coffee beans contain about 800 different compounds, with scents ranging from spicy and sweet, to floral, fruity and smoky. There’s even one compound, furfurylthiol, which scientists say contributes its own unique “coffee aroma.” For most of us, the combination of scents heightens our anticipation and our appetite, delivering the clear message that it’s coffee time.

The primary benefits of coffee in the morning, though, stem from the fact that caffeine is a powerful stimulant. (It’s actually the most commonly-used psychoactive drug in the world.) For that reason, coffee really does wake you up. And it works in an interesting way.

The body regularly releases molecules known as adenosine, which attach to adenosine receptors in the brain and regulate the sleep-wake cycle. Adenosine tells the body to get tired; more and more of it is released during the day.

However, caffeine molecules look and act very much like adenosine. When you consume caffeine, it attaches to the adenosine receptors – and blocks adenosine from delivering it’s “you are getting sleepy” messages. So in reality, caffeine doesn’t wake you up. It stops you from being tired.

Adenosine plays another important role in the brain: it regulates “feel-good” and “fight or flight” hormones like serotonin, dopamine and adrenaline, and keeps us from getting too amped during the day. But when caffeine blocks the adenosine receptors, there’s nothing to prevent the hormones from running wild – explaining the energy boost we get from a cup of coffee (or any other caffeinated beverage).

Finally, studies have shown that caffeine may enhance important brain functions like alertness, memory performance and information processing. When you combine being “more awake” with extra energy and better cognitive performance, you’ve got the magic that a morning cup of coffee delivers at the start of the day.

Herbal tea and hot chocolate may taste good, but they’re simply not going to kick-start your body and brain like coffee does.