What’s the Best Roast for Cold Brew? Using Science to Find the Best Cold Brew Roast

I’m a huge fan of cold brew coffee. I don’t just love it because it’s convenient, but also because it’s delicious, lacks bitterness, and has a lovely smooth texture. Over the years, I’ve spent a ton of time and money doing personal research to find the best roast for cold brew at home. In this article, I’ll share everything I’ve learned through my experiments to help you step up your own cold brew game.

Understanding Cold Brew and Why Roast Level Matters

Before we dive into choosing the perfect coffee and roast for cold brew, it helps to understand the science behind cold brew and why the roast level you choose even makes a difference.

Cold brew coffee is made by steeping coarsely ground coffee in room temperature or cold water for 12 to 24 hours. This long, cold extraction draws out the sweeter, less acidic compounds from the coffee beans and leaves behind the bitter, acidic ones. The result is a naturally sweeter, smoother, and less acidic coffee than conventional hot coffee.

The reason the roast level you choose matters is that roasting transforms the chemical composition of the coffee beans. The longer the beans roast, the more aromatic compounds are developed but also destroyed through caramelization and pyrolysis reactions.

So, darker roasts have less acidity but also fewer aromatic compounds for sweetness and complexity. This significantly affects the flavor you’ll get in cold brew, and it means that there’s ONE best roast for cold brew…although that might differ based on your personal taste.

How and Why Does Cold Brew Taste Different From Hot-Brewed Coffee?

Cold brew coffee has a markedly different flavor profile from coffee made with hot water. The cold water extraction preserves many aromatic compounds that hot water breaks down. Specifically, cold brew retains more:

Sweetness: Compounds like saccharides and polysaccharides don’t extract well in hot water. Cold water pulls them out better.
Fruitiness: Esters and aldehydes like isoamyl acetate (banana) and 2-methylbutanal (dark chocolate) remain intact in cold brew coffee.
Bright Acidity: Acids like malic, citric, and quinic acid are preserved rather than neutralized or denatured by heat.
Tea-like qualities: Catechins and tannins extract well in cold water, lending an almost tea-like astringency in some cases.

The extended brew time of cold brew also extracts more caffeine and soluble coffee solids, lending cold brew a perceived fuller body despite less actual body from emulsified oils.

Conversely, hot coffee brewing causes two key flavor changes:

Bitterness: Hot water readily extracts bitter compounds like trigonelline and quinic acid. Prolonged exposure to heat also breaks down the cell walls of the coffee, leading to bitter coffee flavor.
Low Acidity: Heat neutralizes malic and citric acids, reducing bright acidity. You can still get acidic hot coffee, but the acidity will be less nuanced and bright.

So in summary, cold brew highlights fruity, floral, and tea-like qualities with a smooth mouthfeel. Hot coffee showcases nutty, roasted flavors with more body and bitterness. Quite different flavor experiences…and that’s why the best roast for cold brew isn’t necessarily the best one for hot brewing methods.

How Roast Level Affects the Flavor of Your Coffee

The degree to which coffee beans are roasted has a monumental impact on the flavors extracted into cold brew. Here’s an exhaustive look at what happens during roasting and how it transforms the bean’s chemical composition.

In roasting, heat causes two key chemical reactions:

Caramelization: Sugars and amino acids react to form aromatic compounds and brown pigments. This reaction requires temperatures of 230 to 450 degrees (F) and happens early in light roasts.
Pyrolysis: Between 446 and 464 degrees (F) and beyond, oils start decomposing into even more new flavor compounds. Many are volatile though and degrade with prolonged roasting.

So, in light roasts, you get more sugars and amino acids. As roasting progresses, these convert to aromatic compounds that provide sweetness and flavor top notes. After pyrolysis commences, you start losing many of these volatiles but develop more roast character.

In cold brew, the implications are as follow:

Light roasts retain more sugars and fruitiness.
Medium roasts provide naturally sweet coffee flavors and balanced roast character.
Dark roasts have intense roast flavor but a touch less complexity.

Let’s explore how this manifests in various roast levels when cold brewed.

Cinnamon Roast for Cold Brew

Cinnamon is the lightest roast, taken out of the roaster right at the beginning of first crack where the bean temperature reaches around 385 degrees (F). Beans will be a very light brown and have a powdery surface. The flavor is bright and tea-like with hints of graininess.

When cold brewed, a cinnamon roast retains its origin character and delicate fruity notes well. You’ll taste a bit of sweetness from preserved sugars. But the grassy, cereal-like flavors will overpower the coffee along with a distinct under-roasted greenness, kind of like a tomato-y flavor. For cold brew, I find this roast too vegetal and astringent. Most people don’t even enjoy this in hot brewed coffee.

However, if you want to experiment with cold brewing an ultra light roast, use a coarse grind and extended to an 18 to 24 hour brew time as opposed to filtering after 12 hours. This will help extract more sweetness to balance the roast.

City Roast/Light Roast for Cold Brew

The City or light roast takes the beans to around the middle of first crack, when the beans reach an internal temperature of around 400 degrees (F). The beans will be a light to medium brown with a dry surface. Acidity is bright and you can taste notes of toasted grain and grass.

In cold brew, a light roast is quite bright and sweet thanks to the preserved sugars. But those grassy, cereal notes still dominate. There isn’t enough surface oil development or roast character to balance out the undeveloped green flavors, in my opinion. As with cinnamon roast, I find light roast cold brew to be too one-dimensional and vegetal for my tastes.

To improve the flavor if you want to cold brew a light roast, use a very coarse grind and extended brew time around 18 to 24 hours. This helps extract more sweetness and body to balance the grassy flavors, much like with cinnamon roast.

City Plus Roast for Cold Brew

The City Plus or City Medium roast progresses slightly beyond City into the early seconds after first crack. Temperatures reach between 405 and 410 degrees (F). The beans will be a medium brown and have a hint of oil sheen. You’ll taste nuttiness and grain balanced by sweetness.

Cold brewed, a City Plus roast has muted acidity but still some light vegetal flavors. There are some light, bready notes emerging but not enough surface oil development for my tastes. While an improvement over lighter roasts for cold brew, I still find this roast too undeveloped.

As always, a coarser grind and extended brew time will help if you want to cold brew a City+ roast. But I’d personally recommend progressing into the Full City range.

Full City/Medium Roast for Cold Brew

The Full City or medium roast takes the beans through the end of first crack until just before second crack starts at between 410 to 430 degrees (F). The beans will be a medium-dark brown with an oily patchwork surface. Nuttiness increases along with sweetness and body.

Here’s where cold brew starts getting really good in my opinion. At a Full City roast level, there’s enough surface oil to extract sweetness and nutty flavor but still good acidity and fruitiness. You get a great balance of roast character and origin uniqueness. This is a versatile level for cold brew.

As you venture into medium roasts for cold brew, you can begin using a slightly finer grind and a shorter 12 to 18 hour brew time to maximize flavor and smoothness.

Full City Plus Roast for Cold Brew

My absolute favorite roast for cold brew is Full City Plus, taken to just the beginning of second crack when the beans hit temperatures of between 425 and 435 degrees (F). The beans will be dark brown with an oily surface. Richness increases along with bittersweet cocoa flavors.

In cold brew, Full City Plus strikes the perfect harmony in my opinion. There’s dark cocoa sweetness along with nuttiness and caramel from Maillard browning. But you’ll still get enough acidity and fruit qualities coming through from the bean origin. You get an intricate, sweet, chocolatey cold brew that’s incredibly smooth. For most specialty grade coffees, this mid-level roast accentuates complexity and balance.

When cold brewing Full City Plus roasts, a coarse grind and 12 to 15 hour extraction time works beautifully.

Vienna/Dark Roast for Cold Brew

The Vienna or dark roast takes the beans well into second crack and to bean temperatures of between 430 and 440 degrees (F). The beans will be very dark brown, almost black, and coated in oil. Roasty, bittersweet flavors dominate with muted acidity.

It’s true that many people consider dark roast to be the best for cold brew. And there are good reasons why. The extended roasting develops rich dark cocoa and molasses flavors that extract well into cold water. The lack of acidity gives it a super smooth mouthfeel, and the overwhelming bitterness that you might get from brewing this roast in hot water will be significantly reduced.

That said, I personally prefer stopping at Full City Plus instead of a true dark roast. I find that ultra-dark roasting destroys too much of the origin character that makes a coffee unique. The cold brew loses nuance. But a lower-end dark roast still produces outstanding, chocolatey cold brew with great body.

When brewing cold brew with a dark roast, use a coarse grind size and a shorter 10 to 12 hour extraction time. This prevents over-extracting bitter, ashy flavors.

Why Is Dark Roast Considered the Best for Cold Brew?

There are a few key reasons why dark roasts are traditionally considered the best choice for cold brew coffee:

Roast flavor: The long roasting time develops rich, dark chocolate and roasted flavors that extract well into cold water.
Less acidity: Heavy roasting neutralizes virtually all of the bright, acidic compounds, giving dark roast cold brew an incredibly smooth mouthfeel.
Higher solubility: The components in dark roasts are more soluble, yielding more dissolved coffee solids. This creates a fuller-bodied and richer cold brew.
Maillard browning: The high heat breaks down proteins and sugars which react to form rich, nutty, chocolatey flavors.
Caramelization: Similarly, the prolonged heat caramelizes natural coffee sugars into buttery, fudge-like notes.

So, in summary, dark roasts are popular for cold brew because of their rich roast character, lack of acidity, and developed sweetness and body. The high solubility and smoothness make them an easy, crowd-pleasing choice for thick, syrupy cold brew.

Is Espresso Roast Good for Cold Brew?

The term “espresso roast” is confusing because you can use any roast level to pull espresso shots. Espresso refers to a method of high-pressure extraction rather than a specific roast profile.

However, many commercial coffee companies use “espresso roast” to signify a very dark roast, since darker roasts are traditionally considered best for espresso’s thick, concentrated flavor.

So, while “espresso roast” is a vague term and a bit of a misnomer, it typically indicates a dark to very-dark roast level similar to what most people consider best for cold brew. A lower-end espresso roast will likely produce a rich, sweeter cold brew compared to an ultra-dark Italian roast for espresso.

But overall, an “espresso roast” is probably a safe bet for cold brew if you prefer dark roasted flavor.

French Roast for Cold Brew

French roast takes the beans into the very extremes of second crack, with beans reaching between 440 and 455 degrees (F), until they are almost black. They will have an extremely dark oil sheen, and flavors lean towards ashiness and bitterness with barely any bright acidity.

In cold brew, the intense roast flavor of a French roast will be muted slightly. You’ll get less of the ashy and charred flavors. But it will still lack much complexity or origin character. The cold brew will be very heavy, chocolatey, and bitter.

I find French roast cold brew to be monotone and overly roasty. But if you enjoy bold, thick, dark chocolate flavor, a French roast may appeal more to you in cold brew than other methods. Use a slightly coarser grind and the normal 12 to 15 hour brew time to prevent harsh over-extracted flavors.

Italian Roast for Cold Brew

An Italian roast takes the beans past second crack to over 455 degrees (F) until they are shiny black with oil. Flavors are dominated by charcoal, ash, and extreme bitterness with virtually no origin character left. The beans are quite literally burnt.

In my opinion, Italian roast produces unpleasant cold brew. The beans are so far over-roasted that the cold brew tastes flat, dusty, and overly bitter with a chalky texture. Almost no sweetness or acidity remains. I’d suggest avoiding cold brewing beans roasted this dark.

However, if you want to experiment, use an extremely coarse grind and 12 hours as the maximum brew time. But in general, I don’t recommend Italian roasts for any brewing method, especially immersion like cold brew that extracts exponentially more flavor.

Ideal Coffee Characteristics for Cold Brew

Based on all my experimentation and experience, here are the key characteristics I look for when selecting coffee beans and roast levels for cold brew:

Origin: Blends or single origins from Central/South America like Brazil, Guatemala, and Costa Rica. Their chocolate and nutty profiles suit cold brew beautifully.
Processing: Look for washed/wet processed coffees rather than naturals. They have cleaner flavor for cold brew.
Roast: Full City to Full City+ or a lower-end dark roast. Enough roast character without stifling origin complexity.
Body: Medium or medium-high body work well. Provides richness without oiliness.
Acidity: Low to medium acidity gives pleasant brightness without harshness in cold brew.
Sweetness: Look for coffees with notes of chocolate, caramel, brown sugar. Indicates sweeter flavor.

These characteristics help cold brew achieve a smooth, sweet, nuanced flavor without any harsh vegetal or overpowering roasty notes. Let’s explore a few other factors in more detail.

Coffee Origin: Single Origin vs. Coffee Blends for Cold Brew

Single origin simply means coffee from one specific region, farm, or even harvest from a specific farm. Blends combine beans from multiple origins into one. Neither is necessarily better overall. But for cold brew, I tend to prefer blends.

The extended cold water extraction can exaggerate some qualities in single origins, like bright acidity, fruitiness, grassiness, and more. Blending beans balances out these quirks. It creates a smoother, more mellow flavor, which is ideal for cold brew, in my opinion.

That said, many light-roast single origins like Ethiopians still shine beautifully in cold brew. You get intricate tea-like flavors and fruitiness with some nut overtones and chocolate undertones. Just adjust the grind size and brew time to prevent over-extracting any harsh notes.

How to Choose the Best Coffee for Cold Brew

Here’s a summary of my top tips for selecting delicious coffee beans for cold brew:

Choose a mid-level roast like Full City+ that balances sweetness and roastiness.
Look for a smooth, medium body with low-medium acidity.
Pick beans with flavor notes of chocolate, caramel, brown sugar, and hazelnut.
Lean towards blends or origins like Brazil, Mexico, and Guatemala rather than very bright African coffees.
Make sure the coffee is wet processed for a clean flavor.
Look for beans from reputable specialty roasters who offer detailed roast profiles.
Ask to have the beans ground specifically for cold brew unless you have a good burr grinder at home.
Stick to fresh beans roasted within the past 1 to 2 weeks for optimal flavor.

Follow these guidelines to take the guesswork out of picking coffee that will brew into a delicious cold brew every time.

Wrapping Up: What’s the Best Roast for Cold Brew Coffee?

After years of testing and countless batches of cold brew, I’ve concluded that the best roast level for cold brew is Full City+ or Vienna/dark roast. I personally prefer Full City+ for a touch more acidity and fruitiness to counterbalance the dark chocolate notes, but most people agree that Vienna roasts are best for cold brew.

Of course, personal taste is subjective. If you enjoy very dark chocolate flavors, then a lower-end dark French roast can also be great for cold brew. Just avoid roasting all the way to second crack to preserve acidity and prevent ashiness. You may even love light roasts in cold brew…it’s all about experimenting and finding what works for you!

Whichever you prefer, use a coarse grind, filtered water, and high-quality, fresh beans. With the right roast and coffee selection, you can make outrageously delicious cold brew at home that puts any coffee shop to shame.

Frequently Asked Questions

What’s the difference between cold brew and iced coffee?

Cold brew coffee is brewed by steeping ground coffee in cold or room temperature water for 12 to 24 hours. This long, cold extraction results in a naturally sweet, smooth coffee concentrate. Iced coffee is regular hot-brewed coffee that is subsequently chilled and served over ice. The hot brewing makes iced coffee more bitter and acidic compared to cold brew’s sweeter, mellower flavor.

Can you use hot water to make cold brew?

No, hot water should be avoided when making cold brew coffee. The entire point of cold brewing is that using cold or room temperature water for an extended time extracts a different set of compounds from the grounds. This results in a sweeter, smoother tasting coffee. Hot water would cause the same bitterness and acidity that you get with regular drip coffee. The long extraction time would also over-extract the beans. For authentic cold brew flavor, only use cool or cold water in the 12 to 24 hour brewing process.

How long does cold brew last in the fridge?

If kept sealed and refrigerated, fresh cold brew coffee concentrate will last up to 2 weeks before significant flavor deterioration occurs. The chilly temperature prevents microbial growth, too, keeping it safe to drink. After diluting the concentrate with water or milk, the shelf life decreases to about 5 to 7 days. For maximum freshness, aim to drink any prepared or diluted cold brew within one week. The concentrate itself stays good for up to 14 days sealed in the fridge.

Can you use cold brew concentrate in place of espresso?

No, cold brew concentrate won’t work the same as espresso in coffee drinks. While both are concentrated forms of coffee, cold brew lacks the thick texture, bitterness, and foaming ability of espresso. Substituting cold brew concentrate in drinks like lattes and cappuccinos won’t produce the same experience. However, you can make delicious customized drinks by using cold brew concentrate as the base and experimenting with milk, sweeteners, and mix-ins. Enjoy cold brew on its own terms rather than trying to imitate espresso-based beverages.