What Is Flash Brew Iced Coffee?

Flash brew iced coffee is growing in popularity, so we have decided to look further into what this method entails and what makes it different from other cold coffees.

Flash brew iced coffee
Brewing hot pour-over coffee and instantly chilling it by pouring it over ice

One of the best things about coffee is that it can be enjoyed hot or cold. However, making cold-brew coffee can be time-consuming, with some recipes suggesting leaving your coffee grounds in the fridge for at least 24 hours. 

Put simply, that’s not a method that everyone has time for. If it’s a balmy day, you might want a cold coffee without having to give a day’s notice. Thankfully, another brewing process allows you to make iced coffee in the same amount of time you would make a hot cup.

It involves brewing hot pour-over coffee and instantly chilling it by pouring it over ice. The drink produced from that method is known as Japanese-style iced coffee or flash brew iced coffee. Here’s a little more detail.

Making Flash-Brewed Iced Coffee 

The most common way that flashed-brewed iced coffee is made is by brewing drip coffee directly onto ice. The thought process behind this type of brewing is that the coffee cools immediately but maintains the complexity of a hot cup of joe. 

When making this type of coffee, you use the same ratio of water to coffee as you would typically use for your drip coffee maker or Chemex. The key difference is a proportion of that water is frozen as ice and is put underneath in the dripper. The remaining water is heated and used to make the coffee as you usually would.

The hot coffee drips down onto the ice and chills immediately (or, if you prefer, in a ‘flash’). 

Flash Brew vs. Cold Brew Coffee 

Home made cold brew coffee
Cold brew will also have more caffeine since it sits longer before being served

Both flash and cold brew are chilled coffee-making methods, but the two resulting beverages have different flavor profiles. One is brewed using hot water, while the other uses a cold water method. 

The difference in temperatures extracts two distinct flavors. The flash brew method creates more of a light-tasting, fresh-flavored coffee. This is opposed to cold brew, which has a robust and full-bodied taste.

Generally speaking, cold brew will also have more caffeine because it sits for a longer period of time before being served. Thus, more caffeine is extracted from the beans. 

The History and Future of Flash Brew Iced Coffee 

Flash brew iced coffee isn’t a new invention. In fact, this type of coffee was popular in Japan during the 1960s, hence why it is also called Japanese brewed ice coffee. 

Although it has been around a while, flash brew iced coffee is currently having its big moment. In fact, there is even a new technology company taking advantage of the trend. 

The company in question is called Snapchill™ Technology. It creates ways to immediately cool hot drinks without the use of ice. Its Chief Tea & Coffee Officer Ryan McDonnell told Coffee T&I magazine that they’re “developing products that will change how we make cold coffee.” 

He said: “Created to capture, preserve and enhance every distinctive flavor or note of coffee without oxidation, dilution or additives, Snapchilling preserves all the flavors of a hot coffee cold.” 

“Coffee is incredibly volatile at high temperatures. By Snapchilling the coffee, we can experience flavors at a more drinkable temperature without them dissipating into the air. The ability of our Snapchill™ Technology to ‘dial in’ on the precise and ideal temperature for any variety of coffee allows even the most complex of single-origin coffees to shine brighter than before.”

How To Make Flash Brew Iced Coffee 

To make flash brew iced coffee, you will need the following; 

  • A kettle.
  • A drip coffee maker or a Chemex. 
  • About 40. g (1.4 oz of ground coffee).
  • Around 300g (8oz) of water and the same amount of ice. 

Step One – Put the ice in the carafe 

First, fill the carafe of your pour-over brewer with ice. Ideally speaking, you will want to weigh your ice cubes. However, if you don’t have scales to hand, putting them in just above where your brewed coffee would typically reach will work. 

Step Two – Allow the coffee to bloom 

For step two, you should set up your brewer as you normally would for brewing hot coffee. Then pour a small amount of the recently boiled water evenly over the coffee grinds, allowing the coffee to bloom. Around 45 seconds is perfect for this step. 

Step Three – Pour over the hot water

Then proceed to pour the water in as you normally would but at a slightly slower rate. That is because you don’t want to dramatically decrease the water’s usual contact time with the beans when making flash brew, even though you are using less water for the pour-over. 

Step Four – Serve and enjoy

Once all the water has seeped through and your carafe is full, you can pour your crisp and refreshing cold brew into a glass and enjoy. Ensure you spare some time to enjoy the enticing aroma of the drink. 

Ready To Drink Flash Brew Iced Coffee 

If you don’t fancy making flash-brew iced coffee, then you should know that there are several ‘ready to drink’ brands on the market. These brands brew their coffee using hot water, then chill the coffee quickly and package their product to be sold as cold drinks. Here are just a few of the ones we have tried. 

BOSS Coffee

Photo of lighted vending machine
You may have seen it on one of Japan’s vending machine

Boss coffee provides a smooth, rich flavor that isn’t bitter. It’s a delicious cold drink and one that we thoroughly enjoyed when trying it. Here’s what one Amazon reviewer had to say:

“The taste did not have the bitter aftertaste you normally get from cold coffee, which is good. With cream and sweetener, it was even better. I would switch from my normal canned coffee (to this).”

If you have ever traveled to Japan, you may have seen BOSS flash brew coffee for sale in a vending machine over there.

Two Bears Black Coffee

Two Bears is another brand that knows what it is doing when it comes to flash brew iced coffee. The brand’s classic black coffee option is incredibly smooth, frothy, and wonderfully fresh-tasting, thanks to the addition of liquid nitrogen. You can drink it right from the can, but shake it before opening it to mix the nitrogen.

Two Bears Vanilla Frothed Latte 

You don’t have to go for the basic black coffee when it comes to flash brew iced coffees. This Two Bears drink was flashed cold brewed, resulting in a sweet and nuanced cold latte drink. It’s the perfect option for a warm summer’s day when you want something sweet but need a caffeine boost.

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03/07/2024 01:25 am GMT


  • Cian Murray

    Cian Murray is an experienced writer and editor, who graduated from Cardiff University’s esteemed School of Journalism, Media and Culture. His work has been featured in both local and national media, and he has also produced content for multinational brands and agencies. Find Cian on muckrack.com.