[Video Guide] How to Make Japanese Flash Brew Coffee (Better Than Cold Brew in Minutes)

When the heat rises, nothing beats an ice-cold coffee. While cold brew has its place, Japanese-style flash brew delivers a brighter, more complex cup—without the 12–24 hour wait. By brewing hot and chilling instantly over ice, flash brew preserves delicate aromas and brings out floral notes, citrus brightness, and sweetness in just minutes. Here’s how to master this refreshing method at home using a V60 (or any pourover setup).

Frequently Asked Questions:

What is Japanese flash brew?
It’s a method of brewing hot coffee directly over ice, instantly chilling it while preserving delicate aromas and bright flavors.

How is flash brew different from cold brew?
Cold brew steeps for 12–24 hours and tastes smooth but muted. Flash brew is ready in minutes and keeps more acidity, florals, and complexity.

What grind size should I use for flash brew?
Slightly finer than your usual pourover grind, closer to AeroPress size, to ensure enough extraction with less hot water.

What coffee works best for flash brew?
Light roasts shine with this method, highlighting fruity and floral notes, though you can experiment with any beans you enjoy.

Can I use something other than a V60?
Yes—Chemex, Kalita Wave, or other pourover devices work fine. Just adjust the ratio and brew time to match your setup.

Cold brew has long been the go-to for iced coffee, but Japanese flash brew offers something entirely different: speed and vibrancy. Instead of a slow 12–24 hour steep, flash brew is brewed hot, directly over ice, and ready in minutes. The result? A refreshing cup that captures the lively acidity, floral notes, and sweetness of your favorite beans.

To get started, you’ll need 20 grams of coffee, ground slightly finer than you’d normally use for a V60 pourover. Why finer? Since you’re using less hot water than in a standard pourover, the extra surface area helps extract enough flavor before the ice dilutes the brew. Aim for a grind just finer than your typical setting—too coarse will taste weak, too fine will taste bitter.

The recipe uses a 1:15 ratio: 20 grams of coffee, 200 grams of hot water, and 100 grams of ice. Rinse your filter first to remove papery taste, then discard the rinse water. Place 100 grams of ice in your carafe, add the ground coffee to the filter, and start with the bloom. Pour 40 grams of hot water and let it sit for 45 seconds to release CO₂. Then slowly add the remaining 160 grams of hot water in controlled circles, pouring in pulses for even extraction. The total brew should take around 2.5 to 3 minutes.

Once finished, give the carafe a gentle swirl to mix the melted ice. Pour over fresh ice in a glass, and enjoy a crisp, refreshing coffee bursting with flavor. If it tastes too strong, let the ice melt for a minute. If it’s too weak, grind finer next time; too bitter, grind coarser or shorten the brew time.

Light roasts really shine with this method, highlighting fruity and floral notes, but you can experiment with different beans to suit your taste. The beauty of flash brew lies in its flexibility and speed—you’ll have a chilled, café-quality cup in minutes, without sacrificing complexity.

For an easy comparison, try making both cold brew and flash brew with the same beans. Cold brew delivers smoothness, but flash brew captures vibrancy and brightness in a way cold brew never can.

Full Video Transcript: 

"There’s nothing better than an ice-cold coffee when the heat kicks in. Cold brew? It’s okay. But Japanese-style flash brew? Incredible. It’s faster, fresher, and brings out so much more flavor. You get all the bright acidity, floral notes, and sweetness of a great pourover—just ice cold.

Today I’m showing you how to make it using a V60 with a few tweaks to get the absolute best extraction. But if you don’t have one, you can adapt this recipe to work with any pourover setup. Let’s get into it.

My name’s Lizzy, and I’m all about helping you make better coffee at home. If you want to learn more, then subscribe.

So why choose flash brew over cold brew? Cold brew can be delicious, but it takes 12 to 24 hours to steep. It’s smooth, but it loses some of the bright, complex notes that make specialty coffee special. Flash brew, on the other hand, is brewed hot and then instantly chilled over ice. That way, you keep all those delicate aromatics while still getting an ice-cold, refreshing cup. And the best part? It’s ready in minutes.

For this recipe, we’re going to use a 1:15 ratio. That means 20 grams of coffee, ground slightly finer than usual (I’ll explain why in a second), 300 grams of total water, with 200 grams hot and 100 grams in the form of ice. You’ll also need a carafe or server to brew into, a kettle (a gooseneck is ideal, but any will do), a scale, and a timer—because precision matters.

If you don’t have a V60, you can use a Chemex, Kalita Wave, or any other pourover method. Just adjust the ratios depending on your equipment and brew time. Normally for a V60, you’d use a medium grind, but here we’re going slightly finer—closer to what you’d use for an AeroPress. Why? Because we’re using less hot water than usual.

In a standard pourover, all the water passes through the coffee. But here, part of the final brew volume comes from melted ice. That means we need to increase the surface area of the grounds to extract enough flavor with the limited hot water. Grind too coarse, and you’ll get a weak, under-extracted cup. Grind too fine, and it will over-extract and taste bitter. Aim for a grind just finer than your regular pourover setting, and adjust as needed.

Today I’ll be using a Burundi Long Miles Farm natural-processed coffee, which has notes of apple, orange, and cinnamon. Perfect for this brew. And if you’d like to try this or other delicious coffees, we’ve got 20% off—just use the code on the screen and the link in the description.

Let’s start. Place the V60 filter in the dripper and rinse it with hot water to remove any papery taste, then discard the rinse water. Add the ice to the bottom of the carafe. Next, add the ground coffee to your filter and begin with the bloom. Pour 40 grams of hot water over the 20 grams of coffee and let it sit for 45 seconds. This releases CO₂ and prepares the coffee for even extraction.

After the bloom, continue by slowly adding the remaining 160 grams of hot water in gentle, controlled circles. Pour in pulses rather than dumping it all at once—this ensures a more even extraction. The total brew time should be around two and a half to three minutes.

Once the brewing is complete, give the carafe a gentle swirl. This helps mix in the melted ice for an even flavor. Top up a glass with fresh ice, pour your coffee over, and enjoy. The result is a crisp, refreshing iced coffee that keeps all the complexity of those gorgeous single-origin beans.

If the flavor seems a little strong at first, let the ice melt for a minute—it will balance out beautifully. If your brew is too weak, try grinding a little finer next time. If it’s too bitter, grind slightly coarser or reduce the brew time. Light roasts, in particular, really shine with this method, but experiment with different beans to see what you like best.

And that’s it—Japanese flash brew made simple. If you’d like to compare this to our cold brew recipe, click the video here. Or, for something fun, check out our peanut butter iced coffee recipe. Let me know in the comments if you prefer cold brew or iced coffee. Thanks for watching, and I’ll see you in the next video."