Flash Brewed Coffee, or Japanese-style Iced Coffee is a method of brewing iced coffee that's full of flavor and aroma, with no chilling time required.
It’s a testament to the versatility of coffee that it can be drunk either hot or iced and many coffee lovers enjoy it both ways. And then within that versatility there blossoms even greater diversity in brew methods: drip, pour-over, French press, espresso, cold brew...the list goes on.
There’s one method of chilled coffee that’s become increasingly popular in local coffee shops (and the homes of coffee lovers!) because of its ability to preserve the bright, nuanced flavors that can sometimes get lost when coffee is served cold.
Plus, this method earns extra points for its speed. It can be brewed in the same amount of time it takes to make a hot cup, without having to wait for the coffee to cool before enjoying it.
This fast and flavorful variation on iced coffee is what’s called flash-brewed coffee, also known as Japanese-style iced coffee. It’s made by brewing hot coffee directly onto ice, a simple method that allows the coffee to maintain its freshness, since it doesn’t need time to cool to room temperature, and effectively draws out the flavor compounds from the beans by using hot water instead of cold, which can have trouble extracting the compounds. The result is a bright, fresh, iced coffee.
In addition to all the good stuff listed above, it has even more things going for it:
- The aroma is unbeatable
- It pairs amazingly well with pastry
- It’s super refreshing in warm weather
If your local coffee shop doesn’t offer it, not to worry. You can easily make it yourself at home. You just need either a basic pour-over set-up like a Chemex or a trusty drip coffee maker.
How to Make Flash-Brewed Coffee at Home
Equipment and Ingredients
- Gooseneck Kettle
- Scale (Optional)
- Chemex or Drip Coffee Maker
- Coffee, Ground Medium-Fine, 40 g (1.4 oz)
- Filtered water, 300 g (8 oz)
- Ice, 300 g (8 oz)
Method for Pour-over Style
1. Fill your vessel with ice
Grab your Chemex, or whatever pour-over brewer you’re using, and measure out your ice cubes. If you don’t have a scale, you can eyeball it by filling the brewer to just a smidge higher than a typical hot brewed coffee would normally reach.
2. Let your coffee bloom
Set up your filter and fill it with your coffee grinds. Keeping an eye on the time, pour in 80 grams of water that’s just come off the boil, making sure to evenly distribute it amongst the coffee so all of the grinds get nice and saturated. This is known as letting the coffee “bloom” and is a crucial part of the pour-over method. The heated water flushes out carbon dioxide that is stored in the beans, which allows the remaining water to really penetrate the grinds and draw out all the lovely aromatics and oils. Aim for 45 seconds of bloom time.
3. Begin your pour
Pour your water in, starting with the center as usual, but at a slower rate than you normally would. Flash-brewing calls for about half of the water that regular brewing does, but that doesn’t mean you want to halve the water’s contact time with the beans, so it’s important to take a bit longer with your pour. Here’s an easy way to hit the optimal pour time of about two and a half minutes:
- Pour about 150 grams of water and let it drip almost entirely through the coffee bed
- Pour in a little more water (about 25 grams) and let that drip through
- Repeat until all of your water is used up
4. Finish brewing and enjoy
Once all the coffee has dripped through and melted all of the ice (or most of it), your flash-brewed coffee is ready to pour into a glass and drink. Don’t forget to take a moment to enjoy the distinctive aroma.
Method for Drip Coffee Makers
1. Prepare your ingredients
Add 300 grams of water to the coffee maker’s reservoir and 300 grams of ice into the carafe. Turn off the coffee maker’s hot plate, if you can (if your model doesn’t have this option, just skip this step). Then place your filter and grinds in the basket.
2. Make your flash-brew
Turn your coffee maker on and begin the brew. Once it’s finished brewing, it’s ready to enjoy.
Those are the basic guidelines for making flash-brewed or Japanese-style iced coffee. Once you’ve got the hang of it, you can make adjustments to it as you see fit. This method is really simple and works with any pour-over or drip coffee maker you have on hand. All you need to keep in mind is:
- Use the same amount of coffee as you would for a normal hot brew
- Halve the amount of water you’d normally use
- Fill your vessel with ice to just above where hot brewed coffee usually reaches
Other Tips for Flash-Brewed Coffee:
- Use high quality beans. Iced coffee in general, and this method in particular, highlights the flavor profile of the coffee, so if your beans are low quality, you’ll taste it.
- Grinds that look like coarse salt are the ideal size for this brew method.
- Heat your water to between 195 and 205 degrees Fahrenheit for optimal extraction.
- Serve the finished beverage in a tall glass for maximum visual appeal.
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