How to Make Flash Brew Coffee.

Ice and coffee in a glass Chemex brewer

Flash Brewed coffee is also known as Japanese style coffee.   Let’s talk about what Flash Brew Coffee is NOT.  Flash brew is not cold brew coffee, which is coffee brewed with cold water, and the grounds are in contact with the cold water for 8-12 hours.  It’s also not iced coffee, in the sense that iced coffee is brewed then poured over ice, however it is similar.  Flash brewed coffee is coffee that has been brewed and chilled rapidly, locking in maximum flavor, and is served over ice, but more specifically, it's simply coffee that is brewed directly over ice

This method is best done with a pour over style of brewing, but a drip coffee maker can work as well.  

The process of brewing this way remains the same as how you would regularly prepare a pour over or drip coffee, however, you must adjust the recipe to account for the ice. 

The key to this style of brewing is the correct ratio of coffee to water to ice - so it's best to use a scale to weigh out each ingredient. 

We found this to be a great recipe which gives you the ideal ratio of 1:16 (coffee : water) and it’s easy to remember.

  • 1 oz coffee (28.3 grams) 
  • 8 oz water (225 grams)
  • 8 oz ice (225 grams)

However, others say that a coffee to water ratio of 1:17 is good, with 65% of the total water being hot, while the remaining 35% should be ice.  To calculate this ratio, begin with your coffee amount  - in this case 30g coffee. Multiply by 17 to give you the amount of water (510 g).  Multiply 510 by 65% (331 ml) for the hot water and 35% for the amount of ice in weight. (178.5g)

Regardless of which recipe you choose, you will need the following equipment:

  • Pour over dripper of choice (Chemex, Hario V60, Kalita Wave, Origami, etc.) or drip coffee machine
  • Appropriate filter for the brew method you choose
  • Carafe or vessel with a capacity of more than 500 ml
  • Kettle
  • Grinder
  • Scale with a timer (a separate timer is ok too.)

Instructions using a pour over method:

  • Weigh out your coffee and grind it, medium-fine. The coffee will need to be finer than usual for pour over/drip, as you are using less water.
  • Bring your water to 205 degrees
  • Place your filter into your dripper/drip pot, and rinse it through with hot water. Discard the water.
  • Load your weighed amount of ice into the carafe or vessel.
  • Place your ground coffee into your filter.
  • Saturate the coffee bed with 60 grams of water and let the coffee bloom for 30 seconds.
  • Resume pouring in concentric circles, filling in stages (75 grams of water, then 75 grams). Pour slowly, aiming to reach your total brew weight by around 2 minutes.
  • Once the brew water has drained, dispose of the filter and coffee, then serve and enjoy.

Instructions using a Drip Coffee Maker:

  • Use the same amount of coffee as you would for hot brew, half the amount of water you’d normally use, and fill the vessel with ice to just above where hot brewed coffee level would be.
  • 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 your drip machine has this feature.
  • Then place your filter and grinds in the basket.  
  • Turn your coffee maker on and begin the brew. Once it’s finished brewing, it’s ready to enjoy. 

Once you’ve got the hang of it, you can make adjustments to your taste. 

 Other Tips to keep in mind for the BEST 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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