How to Make Iced Coffee with a Chemex: Cold Brew and Flash Brew Methods

When the temperature climbs, your morning pour-over can feel less like a ritual and more like a chore. But you don't have to give up your beloved Chemex just because it's hot outside. With a few simple adjustments, you can turn your favorite coffeemaker into an iced coffee machine that produces bright, flavorful, and refreshing cups all summer long.

In this guide, we'll explore two distinct methods for making iced coffee with a Chemex: cold brew and flash brew. Cold brew is perfect for those who love a smooth, low-acid concentrate that you can mix with milk or water. Flash brew, on the other hand, delivers a vibrant, aromatic cup that's brewed hot and then rapidly chilled over ice. Both methods showcase the versatility of the Chemex, and we'll walk you through each step so you can choose the one that fits your taste and schedule.

Why Use a Chemex for Iced Coffee?

The Chemex coffeemaker is renowned for its ability to produce a clean, sediment-free cup of coffee. Its thick bonded filters remove even the finest particles and most of the oils, resulting in a crisp, tea-like brew that's perfect for chilling. When you make iced coffee with a Chemex, you get a beverage that's free of bitterness and sludge, even when served cold.

Moreover, the Chemex's elegant design and wide range of sizes—from the three-cup to the ten-cup—make it easy to brew small or large batches of cold brew concentrate. And for flash brew, the Chemex's pour-over design allows you to control the extraction precisely, ensuring that your coffee isn't over-extracted when it hits the ice.

• Clean, sediment-free coffee thanks to thick bonded filters
• Versatile sizes for small or large batches
• Precise control over extraction for flash brew

Method 1: Chemex Cold Brew

Cold brew is the ultimate summer coffee: smooth, sweet, and incredibly low in acidity. It's made by steeping coarsely ground coffee in cold water for 12 to 24 hours, then filtering out the grounds. The result is a concentrate that you can dilute with water, milk, or your favorite non-dairy alternative.

To make cold brew in your Chemex, you'll need a coarser grind than you would for a regular pour-over—think kosher salt or breadcrumb texture. Use a ratio of 1 part coffee to 8 parts water (by weight) for a concentrate that's perfect for pouring over ice. If you prefer a ready-to-drink strength, use a 1:12 ratio.

Start by placing a Chemex filter in the top of your coffeemaker and rinsing it with hot water to remove any paper taste. Then, add the coffee grounds to the filter and slowly pour cold, filtered water over them, making sure all the grounds are saturated. Stir gently to ensure even extraction. Cover the top of the Chemex with plastic wrap or a lid, and let it steep at room temperature for 12 to 24 hours. The longer it steeps, the stronger and more chocolatey it becomes.

After steeping, remove the filter and discard the grounds. Your cold brew concentrate is ready! Store it in the refrigerator for up to two weeks. To serve, fill a glass with ice, add equal parts cold brew and water or milk, and enjoy. For a little sweetness, try a simple syrup or a splash of vanilla.

• Use a 1:8 coffee-to-water ratio for concentrate, or 1:12 for ready-to-drink
• Steep for 12–24 hours at room temperature
• Store concentrate in the fridge for up to two weeks

Method 2: Flash Brew (Iced Pour-Over)

Flash brew, also known as Japanese iced coffee, is the perfect method when you want a cup that's bright, aromatic, and ready in under five minutes. The idea is simple: you brew a hot pour-over directly onto ice, which rapidly chills the coffee and locks in the volatile aromatics that are often lost when hot coffee cools slowly.

To flash brew with your Chemex, you'll need to adjust your recipe to account for the ice. A good starting point is a 1:15 coffee-to-water ratio, but with about 30% of the total water weight replaced by ice. For example, for a 300 ml cup, use 20 grams of coffee, 210 ml of hot water, and 90 grams of ice (which is roughly 90 ml). Place the ice directly in the bottom of the Chemex carafe before you start brewing.

Grind your coffee slightly finer than you would for cold brew—similar to table salt. Rinse the filter with hot water, then add the coffee grounds. Pour the hot water in stages: start with a bloom pour (twice the weight of the coffee) and wait 30 seconds, then continue pouring in a slow, circular motion until you've added all the hot water. The hot coffee will melt the ice and chill rapidly, preserving the delicate floral and fruity notes.

Once the brew is complete, give it a gentle swirl to ensure the coffee and melted ice are fully integrated. Serve immediately over fresh ice if you want it extra cold, or pour it straight into a glass. Flash brew is best enjoyed right away, as the flavors will fade if stored.

• Replace about 30% of total water with ice
• Use a slightly finer grind than cold brew
• Serve immediately to enjoy the bright, aromatic profile

Choosing the Right Chemex for Iced Coffee

Whether you prefer cold brew or flash brew, the size of your Chemex matters. For solo iced coffee sessions, the Three Cup Gold Glass Handle Set is a charming and practical choice. It's small enough to brew a single serving of flash brew or a small batch of cold brew concentrate, and the gold handle adds a touch of elegance to your kitchen. If you often entertain or want to make a larger batch of cold brew, the Six Cup Gold Glass Handle CHEMEX® is a better fit. It provides ample capacity for a family-sized batch of concentrate that you can enjoy all week.

No matter which size you choose, the Chemex's glass construction is ideal for iced coffee. It's non-reactive, so it won't impart any off-flavors, and it's easy to clean after a cold brew steep. Plus, the signature wood or glass handle stays cool to the touch, making it comfortable to pour even when the carafe is filled with ice and cold brew.

• Three Cup Gold Glass Handle Set: perfect for personal servings
• Six Cup Gold Glass Handle CHEMEX®: ideal for larger batches
• Glass construction ensures clean, non-reactive flavor

Tips for the Best Chemex Iced Coffee

To get the most out of your iced coffee, start with freshly roasted beans and grind them just before brewing. For cold brew, a coarse grind is essential to prevent over-extraction and bitterness. For flash brew, a medium-fine grind works best. Always use filtered water to avoid any off-tastes, and don't forget to rinse the paper filter before brewing to remove any papery notes.

Another pro tip: when making flash brew, use large ice cubes or even coffee ice cubes. Coffee ice cubes are made by freezing leftover coffee or cold brew in an ice tray. They won't dilute your drink as they melt, keeping your coffee strong and flavorful to the last sip. You can also experiment with adding spices like cinnamon or cardamom to the grounds for a unique twist.

Finally, consider investing in a good grinder. A consistent grind size is crucial for both methods. If you're just starting out, the Starter Kit is a great way to get everything you need, including a Chemex coffeemaker, filters, and a coffee scoop. It's an excellent entry point for anyone new to pour-over coffee.

• Use coffee ice cubes to prevent dilution
• Rinse the filter before brewing to remove paper taste
• Invest in a quality burr grinder for consistency

Making iced coffee with a Chemex is a rewarding way to enjoy your favorite brew all year round. Whether you choose the patience of cold brew or the speed of flash brew, you'll be rewarded with a clean, flavorful cup that highlights the best of your beans. Experiment with ratios, grind sizes, and add-ins to find your perfect summer coffee. For a complete setup, check out the Starter Kit—it has everything you need to start brewing delicious iced coffee at home.