Battle of the Brews: Hot, Iced, and Cold Brew Coffee Explained

For centuries, coffee has been a hot drink—only a hot drink—and many people claim it should stay that way. But recent innovations in coffee brewing have helped us discover not one, but two ways to enjoy coffee cold without destroying its flavor.

Hot coffee, iced coffee, and cold brew coffee. Each style has its ups and downs, its own brewing methods that bring out unique flavors, and things you should not do to avoid a bad brew.

When you know the key differences between these three coffee styles, and can make them at home, a whole new world of coffee possibilities open up.

No more drinking hot coffee on a hot afternoon because that’s the only option. No more extra-sour iced coffee that took three hours to cool in the fridge. Feeling like a coffee cocktail? There’s a coffee style for that.

You’re about to discover how to maximize your coffee enjoyment, including…

• The #1 thing that destroys iced coffee flavor (that most people don’t realize)

• Which type of coffee has ~66% less bitterness and acidity

• How cold water makes good hot coffee

There’s a lot of potential to unlock, so let’s get started.

Hot Coffee: The Essentials You May Not Know

There’s a lot to love about classic hot coffee. Hot water extracts flavors—oils, sugars, acids, other compounds—into the water, creating the final brew.

Since the brewing water is near-boiling, a series of rapid chemical reactions starts as soon as it hits the coffee grounds. This makes brewing hot coffee a fast process, taking just 2-5 minutes to make anywhere from 1-3 cups.

This fast, explosive extraction produces the range of flavor you’re familiar with. Rich flavors and aromas fill the room, a crisp acidity adds a pop, the subtle sugars add sweetness, and deep earthy or chocolate-y notes (with a hint of pleasant bitterness) round it all out to form a complex, balanced brew.

You can enjoy your coffee black (our favorite way!), or get a little creative. Warm milk smoothes out the lower notes for a more agreeable flavor. Cinnamon sticks and honey can be added to beans with heavy chocolate notes for an Autumn-inspired treat.

Hot Coffee Overview

Flavor: Full-flavored with a bright acidity and balanced bitterness

Caffeine: 80-120mg per 8-ounces

Time: 2-5 minutes

Makes: 1-3 cups per session

Creativity: Low, only warm drinks

Perfect For: Cool mornings, cozy evenings with a book, a brisk walk outside

Iced Coffee: Flash Chilled And Refreshing

The old way of making iced coffee—brewing it hot, waiting for it to cool, and sticking it in the fridge—created a notoriously bitter flavor. The hot water would start all those chemical reactions, but since the coffee stayed hot for hours, those chemical reactions would keep happening, breaking down all the tasty sugars and acids into bitter, bad-tasting compounds.

It was a shame. A bitter, disappointing one. Thankfully, there’s a better way.

“Flash chilled” iced coffee is hot coffee that’s brewed directly over ice.

You get the best of both worlds. The hot water launches that chain of chemical reactions that produces a rich, bright flavor. But as the hot coffee drains over the ice, it chills instantly, stopping those chemical reactions so the flavors don’t break down slowly.

You end up with an iced coffee with all the flavors you love. The natural sugars, the bright acids, the balanced lower-notes, the caffeine. It’s all there—just iced. And since your tongue more easily perceives sweeter flavors at cold temperatures, flash chilled iced coffee tends to taste extra-sweet and tangy (without any sugar added).

The brewing process is a little more challenging since you have to account for ice-melting with less water, but adapting your regular recipe is simple: just remove 40% of the water you’d normally brew with, and replace it with ice in your glass.

It’s hard to beat iced coffee black, but there are a few ways you can customize your brew. Top with cream, mix in some vanilla syrup, or even add a fresh mint garnish. 

Iced Coffee Overview

Flavor: Full-flavored, with some extra tang and sweetness

Caffeine: 80-120mg per 8-ounces

Time: 2-5 minutes

Makes: 1-2 cups per session

Creativity: Low, only cold drinks

Perfect For: Warm afternoons, sunny walks in the park, bright-skied road trips

Cold Brew Coffee: A Whole New World Of Flavor

Hot coffee and iced coffee are very similar, just enjoyed at different temperatures. Cold brew coffee, on the other hand, is another beast entirely.

Made using cold water, cold brew coffee has a flavor unlike any other kind of coffee—and it allows you to get wildly creative.

The cold water doesn’t launch that chain of fast chemical reactions. Instead, the flavors from the coffee grounds are slowly extracted over the course of hours as the grounds and water steep together. But not all the same flavors. 

Without the near-boiling water, many of the acids and bitter compounds remain trapped in the grounds (the cold water can’t break them down), never making it to your final brew.

This means that cold brew coffee has up to 66% less acidity and bitterness. The flavors you can taste are presented differently than they would be in hot coffee. They’re smoother, less abrasive. And where aromatic compounds would normally rise from your mug as vapor, with cold brew, they’re still stuck in liquid form, giving cold brew coffee a reputation for incredibly rich aromas.

As if that’s not crazy enough, cold brew coffee is typically brewed as a concentrate. Since you’re brewing over the course of ~12 hours, you’re not restricted to the usual coffee-to-water ratios that help hot coffee taste balanced. It’s why most people make their cold brew 2-3x as strong. The concentrate is easier to store and is extremely versatile.

The obvious drink is iced cold brew coffee. Mix an ounce of cold brew concentrate with simple syrup and soda water for a coffee soda. Add milk for a cold brew iced latte. Shake with vodka and sugar for an evening cold brew martini. You can even add hot water for a different take on hot coffee. 

The possibilities are endless. 

Cold Brew Coffee Overview

Flavor: Rich, full-bodied, sweet, low acidity and bitterness

Caffeine: 160-300 mg per 1-ounce of concentrate

Takes: ~12 hours

Makes: 1-8 cups per session

Creativity: High, virtually no limit to what you can do

Perfect For: Warm afternoons, creative exploration, cocktail night, and beyond

The world of coffee is diverse, fascinating, and richly flavorful. Go explore!

Happy brewing,

Your friends at ESPRO