Cold Brew Coffee Using An Aeropress: A Guide

Quick Answer

• Use the inverted Aeropress method for a mess-free cold brew.
• Aim for a coarse grind, similar to sea salt.
• A 1:8 coffee-to-water ratio is a good starting point.
• Steep for 12-24 hours at room temperature or in the fridge.
• Press slowly and gently to avoid sediment.
• Dilute the concentrate to your preferred strength.

Who This Is For

• Coffee enthusiasts looking to experiment with cold brew at home.
• Aeropress owners who want to leverage their existing equipment for a new brewing method.
• Individuals seeking a smoother, less acidic coffee experience.

What to Check First

Brewer Type and Filter Type

The Aeropress is your brewer for this guide. You’ll be using the standard Aeropress paper filters, or if you have one, a reusable metal filter. Paper filters will yield a cleaner cup with fewer fines, while metal filters allow more oils and sediment through, resulting in a richer, fuller-bodied brew. Ensure your Aeropress is clean and all parts are present.

Water Quality and Temperature

Start with good quality water. Filtered tap water is ideal; avoid distilled water as it lacks the minerals that contribute to coffee flavor. For cold brew, the brewing temperature is ambient, meaning room temperature or refrigerator temperature. You do not need to heat the water.

Grind Size and Coffee Freshness

The grind size is crucial for cold brew. You want a coarse grind, resembling coarse sea salt or breadcrumbs. If the grind is too fine, you risk over-extraction, bitterness, and difficulty pressing. If it’s too coarse, the brew might be weak. Freshly roasted and ground coffee will always yield the best results. For cold brew, coffee ground a few days to a couple of weeks after roasting is generally preferred over very fresh beans, as it can be less acidic.

Coffee-to-Water Ratio

A common starting point for cold brew concentrate is a 1:8 ratio of coffee to water by weight. For example, if you use 30 grams of coffee, you would use 240 grams (or ml) of water. This will produce a concentrate that you’ll dilute later. You can adjust this ratio based on your preference for strength.

Cleanliness/Descale Status

Ensure your Aeropress and any containers you use are thoroughly clean. Coffee oils can build up and impart stale flavors. If you haven’t descaled your Aeropress (or any other coffee equipment you use), it’s a good time to do so. Mineral buildup can affect the taste of your coffee.

Step-by-Step: How to Make Cold Brew Coffee Aeropress

1. Assemble the Aeropress Inverted: Insert the plunger into the brew chamber just enough to create a seal, about 1 inch. This prevents coffee from dripping through prematurely.

• What “good” looks like: The plunger is seated securely, and the Aeropress can be held upside down without coffee leaking.
• Common mistake and how to avoid it: Not inserting the plunger far enough, leading to leaks. Ensure a good seal before proceeding.

2. Add Coffee Grounds: Place your Aeropress, now inverted, on a stable surface. Add your coarsely ground coffee to the brew chamber. For a standard Aeropress, start with about 15-20 grams of coffee.

• What “good” looks like: The grounds are evenly distributed in the chamber.
• Common mistake and how to avoid it: Using a grind that is too fine. This can clog the filter and make pressing difficult. Stick to a coarse grind.

3. Add a Small Amount of Water (Bloom): Pour just enough cool or room temperature water over the grounds to saturate them. This is the “bloom” phase. Let it sit for about 30 seconds.

• What “good” looks like: The coffee grounds will expand and release CO2, appearing wet and slightly bubbly.
• Common mistake and how to avoid it: Skipping the bloom. This can lead to uneven extraction.

4. Add Remaining Water: Gently pour the rest of your cool or room temperature water over the grounds. For a 1:8 ratio with 20g of coffee, you’d add about 160g (ml) of water.

• What “good” looks like: The water is evenly distributed throughout the coffee grounds.
• Common mistake and how to avoid it: Pouring too aggressively, which can disturb the coffee bed and lead to channeling.

5. Stir Gently (Optional but Recommended): Give the coffee and water mixture a gentle stir with a non-metal stirrer (like a chopstick or the Aeropress stirrer) to ensure all grounds are fully saturated.

• What “good” looks like: All visible coffee grounds are wet.
• Common mistake and how to avoid it: Over-stirring, which can break up the grounds and lead to a muddy brew.

6. Cap and Steep: Place the filter cap onto the Aeropress, securing it tightly. You can either leave the Aeropress at room temperature or place it in the refrigerator for steeping.

• What “good” looks like: The cap is securely fastened, creating a sealed environment.
• Common mistake and how to avoid it: Not securing the cap properly. This could lead to spills when you move it.

7. Steep for 12-24 Hours: Allow the coffee to steep. Shorter steeps (12-15 hours) will be lighter; longer steeps (18-24 hours) will result in a more concentrated and intense flavor. Experiment to find your preference.

• What “good” looks like: The coffee is steeping undisturbed.
• Common mistake and how to avoid it: Steeping for too short a time (under 12 hours) or too long (over 24 hours), which can result in a weak or overly bitter brew, respectively.

8. Remove from Fridge/Room Temp: Once steeping is complete, take the Aeropress out. If it was in the fridge, let it sit at room temperature for about 15-30 minutes to make pressing easier.

9. Flip and Prepare to Press: Carefully flip the Aeropress over onto a sturdy mug. Ensure the mug is stable and can handle the pressure.

• What “good” looks like: The Aeropress is stable on the mug, ready for pressing.
• Common mistake and how to avoid it: Using a mug that is too small or unstable, increasing the risk of spills or breakage.

10. Press Slowly and Gently: Press down on the plunger slowly and steadily. Aim for about 20-30 seconds of pressing. You should feel some resistance.

• What “good” looks like: The coffee is being pushed through the filter smoothly, with even pressure.
• Common mistake and how to avoid it: Pressing too hard or too fast. This can force fine grounds through the filter, creating sediment and bitterness. Stop pressing when you hear a hissing sound.

11. Dilute and Serve: The liquid collected is a concentrate. Dilute it with cold water or milk to your desired strength. A common starting point is a 1:1 or 1:2 ratio of concentrate to diluent.

• What “good” looks like: Your diluted coffee tastes balanced and refreshing.
• Common mistake and how to avoid it: Not diluting the concentrate enough, resulting in an overly strong and potentially bitter drink.

12. Clean Your Aeropress: Immediately after brewing, disassemble and clean your Aeropress. This prevents coffee oils from building up.

• What “good” looks like: All parts of the Aeropress are clean and dry.
• Common mistake and how to avoid it: Leaving the Aeropress dirty. This can affect the taste of future brews.

Common Mistakes (and What Happens If You Ignore Them)

| Mistake | What It Causes | Fix