How Dunkin’ Donuts Makes Their Signature Cold Brew Coffee

Quick answer

• Dunkin’ uses a specific cold brew coffee concentrate, not standard brewed coffee.
• The process involves steeping coarse-ground coffee in cold water for an extended period (typically 12-24 hours).
• The resulting concentrate is then diluted with cold water and served over ice.
• Key factors for a good cold brew are coffee-to-water ratio, grind size, and steeping time.
• Freshly roasted, quality coffee beans are crucial for optimal flavor.
• Cleanliness of equipment prevents off-flavors and ensures consistent taste.

Who this is for

• Home brewers curious about replicating Dunkin’s cold brew experience.
• Coffee enthusiasts looking to understand the cold brew process for consistent results.
• Anyone frustrated with bitter or weak homemade cold brew coffee.

What to check first

Brewer type and filter type

Most cold brew systems are simple immersion brewers. This means the coffee grounds are fully submerged in water. You’ll need a large container, ideally with a spigot, or a French press. For filtering, a fine mesh filter, cheesecloth, or specialized cold brew filter bags are common.

• Good looks like: A system that allows for complete coffee immersion and easy, sediment-free straining.
• Common mistake: Using a standard drip coffee maker or espresso machine; these are designed for hot brewing and won’t produce cold brew.

For filtering, a fine mesh filter, cheesecloth, or specialized cold brew filter bags are common. These filter bags make the straining process much easier and cleaner.

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Water quality and temperature

Cold brew, by definition, uses cold water. Filtered water is highly recommended to avoid introducing off-flavors from chlorine or minerals often found in tap water. The initial water temperature should be cold, straight from the tap or refrigerated.

• Good looks like: Clear, odor-free, filtered water at refrigerator temperature.
• Common mistake: Using warm or hot water, which will extract different compounds and lead to a different flavor profile than true cold brew.

Grind size and coffee freshness

For cold brew, a coarse grind, similar to sea salt or breadcrumbs, is essential. This prevents over-extraction and excessive bitterness during the long steeping process. Use freshly roasted coffee beans, ideally ground just before steeping, for the best flavor.

• Good looks like: Uniform, coarse grounds that feel gritty between your fingers. Coffee beans roasted within the last 2-3 weeks.
• Common mistake: Using a fine grind (like for espresso or drip coffee), which results in over-extraction, bitterness, and a muddy final product. Stale coffee leads to flat, lifeless cold brew.

Coffee-to-water ratio

The ratio is crucial for cold brew concentrate. A common starting point is a 1:8 coffee-to-water ratio by weight (e.g., 1 part coffee to 8 parts water). This produces a strong concentrate that you’ll dilute later.

• Good looks like: A ratio that yields a strong, flavorful concentrate, allowing for later dilution without losing character.
• Common mistake: Using too little coffee, resulting in a weak concentrate, or too much water, leading to a watery final product after dilution.

Cleanliness/descale status

All equipment used for cold brew, from the steeping container to the filter, should be meticulously clean. Coffee oils can build up and become rancid, imparting off-flavors to your brew. Regular cleaning with soap and water is sufficient; descaling isn’t typically relevant for cold brew unless using specific cold brew machines with internal components.

• Good looks like: Spotless equipment, free from visible residue or oily films.
• Common mistake: Brewing in a container with old coffee residue or uncleaned filters, which can make your cold brew taste sour or bitter.

Step-by-step (brew workflow)

1. Gather your ingredients and equipment:

• What to do: Have your coarse-ground coffee, filtered cold water, steeping vessel, and filtering equipment ready.
• Good looks like: Everything is clean, and you have enough coffee and water for your desired batch size, typically using a 1:8 coffee-to-water ratio by weight.
• Common mistake: Forgetting a key piece of equipment or not having enough coffee; avoid this by planning ahead.

Gather your ingredients and equipment: Have your coarse-ground coffee, filtered cold water, steeping vessel, and filtering equipment ready. A large glass jar with a lid is perfect for steeping your coffee grounds.

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2. Measure your coffee and water:

• What to do: Use a kitchen scale to accurately measure your coarse-ground coffee and cold, filtered water according to your chosen ratio (e.g., 8 oz coffee to 64 oz water).
• Good looks like: Precise measurements ensure consistent strength and flavor.
• Common mistake: Estimating measurements by volume instead of weight, which can lead to inconsistent results due to varying coffee density.

3. Combine coffee and water:

• What to do: Place the coarse coffee grounds into your steeping vessel. Slowly pour the measured cold water over the grounds, ensuring all grounds are fully saturated.
• Good looks like: All coffee grounds are submerged and visibly wet.
• Common mistake: Not fully saturating the grounds, leading to dry pockets and under-extraction; gently stir to ensure full saturation.

4. Steep the mixture:

• What to do: Cover the vessel and let it steep at room temperature or in the refrigerator for 12 to 24 hours. Longer steeping times generally result in a stronger concentrate.
• Good looks like: The mixture sits undisturbed for the chosen duration.
• Common mistake: Steeping for too short a time (weak brew) or too long (over-extracted, bitter brew); experiment to find your preferred steeping time.

5. Prepare for filtration:

• What to do: Set up your chosen filtration system. This might involve placing a fine-mesh strainer lined with cheesecloth over another container, or using a specialized cold brew filter.
• Good looks like: A clean, stable setup ready to receive the brewed concentrate.
• Common mistake: Not having a proper filtering setup, which can lead to sediment in your final product.

6. Filter the concentrate:

• What to do: Slowly pour the steeped coffee mixture through your filtration system. Allow gravity to do the work; do not press or squeeze the grounds.
• Good looks like: A clear stream of dark brown concentrate drips into your clean collection vessel, free of large coffee particles.
• Common mistake: Squeezing the grounds, which can force fine particulates and bitter oils into the concentrate, making it cloudy and harsh.

7. Store the concentrate:

• What to do: Transfer the filtered cold brew concentrate to an airtight container and store it in the refrigerator.
• Good looks like: A sealed container of rich, dark cold brew concentrate.
• Common mistake: Storing in an open container, which can lead to oxidation and absorption of refrigerator odors, diminishing flavor.

8. Dilute and serve:

• What to do: When ready to drink, dilute the concentrate with cold water (or milk) to your preferred strength, typically a 1:1 ratio. Serve over ice.
• Good looks like: A refreshing, smooth cold brew, perfectly balanced to your taste.
• Common mistake: Drinking the concentrate undiluted (too strong) or over-diluting it (too weak); adjust the ratio based on personal preference.

Common mistakes (and what happens if you ignore them)

Decision rules (simple if/then)

• If your cold brew tastes too weak, then increase the coffee-to-water ratio slightly (more coffee) or steep for a longer duration (up to 24 hours) because it’s under-extracted.
• If your cold brew tastes too bitter or astringent, then use a coarser grind or reduce the steeping time because it’s over-extracted.
• If your cold brew is cloudy or has sediment, then use a finer filter or avoid squeezing the grounds during filtration because fine particles are passing through.
• If your cold brew has an off-flavor, then check your water quality and ensure all equipment is meticulously clean because impurities or old coffee oils can be the cause.
• If you prefer a milder cold brew, then dilute your concentrate with more water or milk because the concentrate is designed to be strong.
• If you’re short on time, then consider a slightly higher coffee-to-water ratio (e.g., 1:7) for a stronger concentrate in less steeping time because it allows for quicker extraction.
• If your cold brew tastes flat or lacks aroma, then use fresher roasted coffee beans and grind them just before brewing because fresh coffee is key to vibrant flavor.
• If you want a less acidic cold brew, then cold brewing is already a good choice, but ensure a coarse grind and avoid over-steeping because these can still introduce some acidity.
• If your cold brew concentrate doesn’t last long enough, then make a larger batch, maintaining the same coffee-to-water ratio, because it stores well in the refrigerator for up to two weeks.
• If your cold brew tastes watery after adding ice, then dilute your concentrate less initially or use coffee ice cubes because melting ice dilutes the drink further.

FAQ

What kind of coffee does Dunkin’ use for cold brew?

Dunkin’ typically uses a proprietary blend of 100% Arabica beans for their cold brew. While the exact blend isn’t publicly disclosed, Arabica beans are known for their smoother, less bitter flavor profiles, which are ideal for cold brewing. For home brewing, look for medium to dark roast Arabica beans.

How does Dunkin’ Donuts make cold brew coffee taste so smooth?

The smoothness comes from the cold brewing process itself. Steeping coffee in cold water for an extended period extracts fewer acidic compounds and bitter oils compared to hot brewing. This results in a naturally smoother, less acidic, and often sweeter concentrate.

Can I use regular ground coffee for cold brew?

While you can, it’s not recommended. Regular pre-ground coffee is usually too fine for cold brew. Using a fine grind can lead to over-extraction, making your cold brew bitter, astringent, and difficult to filter, often resulting in a muddy final product. Always opt for a coarse grind.

How long does Dunkin’ Donuts make their cold brew coffee steep?

Like most commercial cold brew operations, Dunkin’ likely steeps their coffee for an extended period, typically between 12 and 24 hours. This long, slow extraction in cold water is what creates the signature smooth and low-acid concentrate.

What is the ideal coffee-to-water ratio for making cold brew at home?

A common and effective starting point for cold brew concentrate is a 1:8 coffee-to-water ratio by weight. For example, 1 part coffee (e.g., 8 ounces) to 8 parts water (e.g., 64 ounces). You can adjust this slightly based on your preference for strength and later dilution.

How should I store homemade cold brew concentrate?

Store your filtered cold brew concentrate in an airtight container in the refrigerator. This will keep it fresh and prevent it from absorbing other odors from your fridge. Properly stored, cold brew concentrate can last for up to two weeks.

Why is my homemade cold brew bitter?

Bitterness in cold brew is usually a sign of over-extraction. This can be caused by using coffee that’s ground too fine, steeping the coffee for too long, or squeezing the coffee grounds during the filtration process. Try adjusting these variables for a smoother taste.

What this page does NOT cover (and where to go next)

• Specific Dunkin’ brand ingredient details or proprietary recipes.
• Advanced cold brew techniques like nitro cold brew or Japanese-style flash brew.
• Detailed chemistry of coffee extraction or specific compound analysis.
• Equipment reviews or brand comparisons for cold brew makers.
• How to make hot coffee or espresso-based drinks.
• The history of coffee or the cold brew trend.