Flash Brew Coffee Guide: How to Make Iced Coffee Like a Pro

Flash brew is where you brew coffee directly over ice using a pour-over setup. The result is a crisp, iced coffee with similar qualities to cold brew coffee. However, unlike cold brew, flash brew coffee can be made in an instant. 

In this brew guide, you'll learn how to make a refreshing iced coffee using the Japanese flash brew method. If you have a pour-over, high-quality arabica coffee, and some ice, you'll be able to make this delightful beverage in minutes.

Flash Brew Brewing Specs:

• Brew Time: 5 minutes
• Coffee/Water Ratio: 1:15
• Grind: Medium-fine (similar to table salt)
• Water Temperature: 208ºF (98ºC) 
• Recommended Coffee: DaLat Coffee (100% Arabica)

Flash Brew Brewing Summary

1. Boil a kettle of water. 
2. Prepare the pour-over. 
3. Add ice to the collection chamber. 
4. Brew the coffee over the ice. 
5. Add sugar and/or milk (optional).
6. Serve and enjoy.

What You Need to Flash Brew Coffee

You don't need much to make flash brew coffee. However, the quality of your coffee, ice, and water is important if you want to produce the best iced brew. 

Here's what you need to make flash brew coffee:

Tools Needed

1. Pour-Over Device — These manual brewers come in several shapes and sizes, but they all work in the same way. The Hario V60, Chemex brewer, and Kalita Wave are good options. 
2. Coffee Grinder — The best flash brew is made with freshly ground coffee. Use a burr or blade grinder to grind whole beans.  
3. Coffee Measure — Use a coffee scoop or weighing scale to accurately measure the coffee. This will ensure you get the same results every time. 
4. Kettle — Although flash brew is cold, you'll need hot water to brew the coffee. Use an electric or stovetop kettle to heat your water.
5. Serving Glass — Flash brew should be served in a large, clean glass with ice. 

Ingredients

1. High-Quality Coffee — Opt for a high-quality, whole-bean arabica or blend. 
2. Water — Use fresh, filtered water for making flash brew coffee.
3. Ice — You'll need plenty of ice to brew the coffee over.
4. Milk (Optional) — You can add milk to flash brew coffee to create a creamy iced beverage. 
5. Sugar (Optional) — You can add sugar to sweeten your flash brew coffee if desired. 

Coffee Recommendations: Flash Brewing

We recommend 100% arabica coffee for flash brew. The smooth, sweet, bold flavors of arabica make the perfect iced coffee. 

You should opt for a whole-bean arabica such as fruity DaLat Coffee — freshly ground coffee makes the best brew. If you don't want to grind your owfn coffee, make sure to purchase a high-quality, fresh, pre-ground coffee.

If you prefer a stronger iced coffee, try an arabica and robusta blend. Blends such as Saigon OG combine the smoothness of arabica with the dark, bold flavors of robusta. 

Step-by-Step Brewing Instructions: Flash Brewing

Flash Brewing is one of the quickest and easiest ways to make barista-quality iced coffee. 

Here's how to make Flash brew coffee:

1. Boil a Kettle of Water

First, boil a kettle of water. Use fresh, filtered water for the cleanest brew. 

2. Measure and Grind the Coffee

Grind your coffee to a medium-fine consistency (unless your pour-over requires a different grind size). A burr grinder produces the most consistent grind, but blade grinders also work well with pour-over coffee. 

The amount of coffee you use depends on how much flash brew you want to make. 

Use the table below to work out how much coffee and water you need:

Note: The table above is relevant to most pour-overs. However, some, such as the Clever Dripper, may require different coffee-to-water ratios. 

3. Prepare Your Pour-Over

Put a paper filter in your pour-over and place the brewing chamber over your mug or collection chamber. 

Pour some hot water over the filter until it drips through into the container below. Then, discard the water. Doing this removes any impurities in the filter that can taint the taste of the flash brew coffee. 

Once you've done this, add the coffee to the filter and disperse it evenly.

4. Add Ice

Fill your cup or collection chamber with ice and place the brewing chamber on top. 

5. Bloom the Coffee

Blooming the coffee before brewing ensures even extraction. To bloom the coffee pour just enough hot water over the grounds to cover them. Wait for 30 to 45 seconds for the gasses to release fro6.the grounds. 

6. Brew the Coffee

Gently pour your hot water over the coffee, moving in a circular motion slowly. Avoid disturbing the grounds too much — this can lead to over-extraction. 

After 45 seconds to one minute, you'll see the first drips fall into your ice-filled collection chamber. It can take anywhere from three to five minutes for the brewing process to complete. 

7. Customize and Serve

If you brewed the coffee into a collection chamber, pour it into your serving glass. Enjoy it unsweetened and black over ice, or add milk and sugar to taste if you prefer a sweet, milky iced coffee. 

Tips for Flash Brewing Coffee

Flash brew is a simple brewing method for making delicious chilled coffee. However, a few simple tricks ensure you make the best possible brew every time. 

Here are a few tips to follow when making flash brew coffee:

1. Adjust the Coffee-to-Water Ratio

Experiment with your coffee-to-water ratio until you find the perfect strength and flavor for your taste. Different beans and blends may require different ratios to bring out their flavors and aromas. Start with a 1:15 ratio and adjust it as you see fit. 

Less coffee and more water makes a weaker brew; more coffee and less water makes a stronger brew. Arabica and arabica-rich blends may require a higher coffee-to-water ratio to bring out the more subtle notes of the coffee. Robusta and robusta-rich blends may require a lower coffee-to-water ratio to dull the bold, dark, bitter notes of the coffee. 

You may also want to increase the amount of coffee and decrease the amount of water if you want to make milky iced coffee with your flash brew. Making a concentrated flash brew allows you to dilute it 50:50 with milk while retaining the flavor of the coffee. 

2. Always Bloom the Coffee

Always bloom your coffee before brewing. This step should not be overlooked if you want to make barista-quality iced coffee at home. Blooming allows gasses to escape the grounds before brewing, leading to a more evenly-extracted cup of coffee. 

To bloom your coffee, saturate the grounds with water and wait for around 45 seconds before adding the rest of the water. This small step makes a massive difference when it comes to flavor. 

3. Stir the Brew Before Serving

The nature of flash brewing can lead to an uneven brew. As the hot coffee drips over the ice, the ice melts and dilutes the coffee. The finished brew may have layers of stronger coffee and weaker coffee. 

Give your coffee a gentle stir after brewing to ensure the flavors are evenly distributed, and the brew is completely chilled. 

4. Experiment With Bean Type

Experiment with your roast and bean type. Although most people prefer arabica coffee for making flash brew, robusta, blends, and liberican coffee also make interesting chilled coffee. 

Don't be afraid to try out new beans and combinations. 

Robusta beans produce a dark, bold, slightly bitter flash brew with a high caffeine content. Although this can be a little strong for most palates when black, combining it with milk and sugar makes a delightfully rich drink. You can also add sweetened condensed milk to craft a Vietnamese iced coffee. 

Experiment with roast levels, too. Different roasts bring out different characteristics in coffee. Darker roasts tend to be naturally sweeter, bolder, and caramel-like, with notes of nuts and chocolate. Light roasts tend to be more acidic and have notes of citrus, tropical fruit, and floral undertones. Medium roasts have elements from both roast levels. 

5. Store Your Flash Brew Properly

Although flash brew coffee is best consumed fresh, you can make it in bulk and store it in your refrigerator. 

If you want to make flash brew coffee a part of your busy morning routine, consider brewing a large quantity at once. 

Store black flash brew in airtight jars or bottles in the fridge, but make sure to remove the ice first to prevent dilution. When it's time to make a coffee, throw some ice in a glass and pour over a serving of your pre-chilled coffee. 

Flash brew stays fresh in the fridge for three to five days before its flavor starts to degrade noticeably. 

FAQs: Flash Brewed Coffee

Want to learn more about flash brew coffee and iced beverages?

Check out the answers to the FAQs below:

1. What is Flash Brewing Coffee?

Flash brewing is a simple Japanese coffee brewing method that involves making the best pour-over coffee directly over ice. When the coffee drips through the filter, it's instantly cooled and diluted by the ice below. The result is a delicious, balanced cup of iced coffee that can be consumed black or with milk and sugar. 

2. How Much Caffeine in a Cup of Flash Brewed Coffee?

The amount of caffeine in a flash-brewed coffee varies depending on the type of coffee used, the coffee-to-water ratio, and the flow rate on the pour-over used. The average 8 oz (240 mL) cup of flash brew coffee made with 100% arabica contains somewhere between 90 and 160 mg of caffeine. 

3. What’s the Best Coffee for Making Flash Brew Coffee?

The best coffee for making flash brew should be high-quality and freshly ground. Opting for a whole-bean coffee and grinding it just before brewing is the best option. Arabica coffee is a favorite for flash brew coffee because it produces a naturally sweet, smooth, complex brew. Blends can also be used to create a darker brew with a higher caffeine content. 

4. Can You Add Milk to Flash Brew Coffee?

Yes. Although flash brew coffee is traditionally consumed black over ice, you can add a dash of milk and sugar to create a chilled, creamy, indulgent brew. If you want to add milk to your flash brew coffee, increase the coffee-to-water ratio to ensure the flavors of the coffee shine through the dairy. 

5. What is a Pour-Over Coffee Brewer?

A pour-over is a simple manual coffee brewer. A paper filter is added to the brew chamber before adding ground coffee. Hot water is then gently poured over the coffee, and a perfectly extracted brew is collected in a mug or collection chamber below. You can think of a pour-over as a manual drip coffee maker — both work in the same way, but the pour-over provides more control over the extraction process. 

6. Can You Use a Hario V60 to Flash Brew Coffee?

Yes. The Hario V60 is the perfect Japanese pour-over brewer for making flash brew coffee. To use it, simply place it on top of an ice-filled serving glass. Add coffee and gently pour over hot water to extract the coffee. 

7. Can You Make Vanilla Iced Coffee by Flash Brewing?

Yes. You can make vanilla iced coffee using flash brew coffee. Simply brew a concentrated flash brew by increasing the coffee-to-water ratio. Dilute the brew with milk, add vanilla syrup, and stir to combine. 

8. Can You Use a Chemex to Flash Brew?

Yes. You can use a Chemex pour-over to flash brew coffee. Before adding the filter and ground coffee, fill the collection chamber with ice. Brew the coffee as normal, and an iced beverage will form below. 

9. Does Flash Brewing Make Cold Brew Coffee?

No. Cold brew coffee is made by slowly extracting coffee with cold water over a period of 18 to 24 hours. Cold brew coffee is less acidic and produces more delicate flavors. Flash brew coffee is hot brewed coffee that's cooled instantly. This creates a chilled brew with the qualities of regular pour-over coffee. 

10. How Long Will Flash Brew Coffee Keep in the Fridge?

You can keep flash brew coffee in the fridge for three to five days before its flavor begins to deteriorate. Make sure to remove the ice before storage to prevent dilution. 

If you've made too much flash brew coffee with milk, it will keep for one to two days before it begins to turn bad.