What Is Flash Brew Coffee?
Flash brew is coffee brewed hot directly onto ice, so it chills the instant it's made. You brew with less hot water than usual and let ice make up the rest, so the coffee isn't watered down. Because it's brewed hot, flash brew keeps the bright, fruity and aromatic flavors that cold brew loses, and it's ready in about 4 minutes instead of 12 to 24 hours. It's also called Japanese iced coffee, after the style made popular in Japanese coffee shops.
Flash Brew vs. Cold Brew vs. Iced Coffee
| Flash brew | Cold brew | Regular iced coffee | |
|---|---|---|---|
| How it's made | Brewed hot directly onto ice | Steeped in cold water | Hot coffee cooled, then poured over ice |
| Time | About 4 minutes | 12 to 24 hours | Varies |
| Flavor | Bright, clean, aromatic | Smooth, chocolatey, low acidity | Often flat or watery |
| Best coffees | Fruity single origins, lighter roasts | Medium and dark roasts | Any |
| Caffeine | About the same as hot coffee | Usually higher (more coffee used) | About the same as hot coffee |
Prefer something smooth and mellow? See our guide on how to make cold brew at home.
Why Flash Brew Tastes Better Than Regular Iced Coffee
Hot water pulls out a coffee's full range of flavors, including the fruity acids and aromatic oils that cold water leaves behind. Chilling the coffee right away locks those flavors in before they fade. Regular iced coffee is often brewed hot, left to sit and then poured over ice. That stale, diluted cup is exactly what flash brew avoids.
Flash Brew Coffee Recipe (16 oz)
You'll need: a pour over brewer (like a V60, Kalita Wave or Chemex), a filter, a scale, a kettle, a grinder and a carafe.
| Ingredient | Amount |
|---|---|
| Fresh coffee | 30 g, ground medium-fine, like table salt |
| Hot water (200°F) | 335 g |
| Ice in the carafe | 165 g |
- Add the ice. Put 165 g of ice in your carafe or server.
- Rinse the filter. Set the brewer on the carafe, rinse the filter with hot water, and pour that water out without melting the ice. Rinsing into a separate cup is easiest.
- Add the coffee. Add 30 g of ground coffee and shake it level.
- Bloom. Start a timer and pour 60 g of water to wet all the grounds. Wait 30 to 45 seconds.
- Pour. Pour slowly in circles to 200 g, let it drop, then pour to 335 g total.
- Swirl and serve. The brew should finish around 3 to 3½ minutes. Swirl the carafe until the ice melts, then pour over fresh ice.
The hot water and ice together make 500 g, about a 1:16.7 coffee-to-water ratio, close to our hot pour over recipe. Because the hot water is only two-thirds of the total, grind a little finer than you would for hot pour over to get full flavor.
Can You Flash Brew With a Coffee Maker?
Yes. Fill the carafe about one-third of the way with ice, then brew with the normal amount of coffee but only about two-thirds of the usual water. Roughly 60 g of coffee, 670 g of water and 330 g of ice makes about a liter. Swirl to melt the ice and serve over fresh ice. An AeroPress works too: brew a strong cup straight onto ice.
The Best Coffee for Flash Brew
Flash brew shows off fruity, bright coffees. A natural process Ethiopian with notes of berry and citrus tastes almost like iced tea or juice. If you like a sweeter, rounder iced coffee, use a medium roast like Abstract Blend (honey, berry, cacao) or Loom Blend (nutty, toffee, chocolate). Use beans roasted within the last few weeks. We print the roast date on the bottom of every bag.
Quick Answers
What is flash brew coffee?
Coffee brewed hot directly onto ice so it chills instantly. It keeps the bright, aromatic flavor of hot coffee in an iced drink.
Is flash brew the same as Japanese iced coffee?
Yes. Both names describe brewing hot coffee directly onto ice.
Is flash brew stronger than cold brew?
Usually not. Cold brew uses more coffee, so it often has more caffeine. Flash brew has about the same caffeine as a hot cup of the same size. See how much caffeine is in coffee.
Is flash brew more acidic than cold brew?
Yes, it tastes brighter. Hot water extracts more of the coffee's natural acids, which is where the fruity, lively flavors come from. Cold brew is smoother and lower in acidity.
How long does flash brew last?
It's best fresh, within a few hours. Unlike cold brew concentrate, it doesn't keep well for days.
What grind size is best for flash brew?
Medium-fine, about like table salt, a little finer than regular pour over.
