Cold Brew vs Iced Coffee: Strength, Acidity and Taste

Both drinks are served cold. The difference is the water temperature while the coffee brews. Cold brew never meets hot water. Iced coffee is regular hot coffee that gets chilled.

That one change affects how fast flavor comes out, which compounds dissolve, and how the drink tastes. Below we compare the two, then suggest coffees from our catalog for each.

What is the difference between cold brew and iced coffee?

Cold brew is steeped in cold or room-temperature water for hours, then filtered. Iced coffee is brewed with hot water in minutes, then cooled or poured over ice. Cold brew usually tastes rounder and less sharp. Iced coffee keeps more of the bright, fruity flavors you get from hot coffee.

Acidity rows from Rao and Fuller, Scientific Reports (2018).

How is cold brew made?

Cold brew is made by mixing coarse ground coffee with cold or room-temperature water, letting it steep for many hours, then straining out the grounds. Most guides call for 12 to 24 hours. Because cool water extracts slowly, cold brew uses more time, and usually more coffee, than a hot cup.

The steep time may be longer than needed. In a 2017 study in Scientific Reports, chemists Megan Fuller and Niny Rao at Thomas Jefferson University found that caffeine and a key chlorogenic acid in cold brew were close to fully extracted after about 400 minutes, or just under 7 hours. Steeping longer added little of either. Flavor is another matter, and many people still prefer an overnight steep.

A lot of cold brew is made as a concentrate, with a high dose of coffee to water, then cut with water, milk or ice before drinking. That is why cafe cold brew can taste strong even after the ice melts.

Grind coarse so the grounds are easy to filter and the brew doesn't turn muddy. Some roasters sell coffee already ground for cold brew, which saves a step if you don't own a grinder.

How is iced coffee made?

Iced coffee is regular hot-brewed coffee served cold. You can brew it normally and chill it, or brew it hot directly onto ice, often called flash brewing or Japanese-style iced coffee. Brewing onto ice cools it within seconds, which keeps more aroma and brightness than letting a pot sit and cool.

Simply pouring fresh hot coffee over a glass of ice gives you a weak drink, because the melting ice dilutes it. The fix is to brew stronger. With a pour-over or drip brewer, put part of your water in the carafe as ice and brew the rest hot over the grounds, keeping your usual amount of coffee. The total liquid stays the same, so the final drink tastes like a normal cup.

If you already brew hot coffee, iced coffee needs no new gear. Our beginner home brewing guide (Lesson 03) covers the basic hot method you start from.

Is cold brew stronger than iced coffee?

Cold brew is often stronger in practice because it is usually made with more coffee per ounce of water. At the same ratio, research finds the two are fairly close. A 2017 study measured somewhat more caffeine in coarse-ground cold brew than in hot brew, while medium-ground samples showed no significant difference.

In that Fuller and Rao study, a medium roast coarse-ground cold brew measured about 1,230 mg of caffeine per liter against 970 mg/L for the matching hot brew. For a dark roast, the numbers were 990 and 840 mg/L. The study used one coffee, Kona beans, and small samples, so treat it as a guide and not a rule.

Ratio swamps all of this. A concentrate steeped at double strength and served over a little ice will deliver far more caffeine than a cup of iced coffee brewed at normal strength. For a baseline, Mayo Clinic lists an 8 oz cup of brewed coffee at about 96 mg. The FDA cites 400 mg a day as an amount not generally linked to negative effects for most healthy adults.

Roast level matters less than ratio. The study found medium roasts slightly higher in caffeine than dark roasts in both methods. We look at that question in detail in Does dark roast have more caffeine? (Lesson 04).

Is cold brew less acidic than iced coffee?

Partly. A 2018 study in Scientific Reports found cold brew and hot coffee have nearly the same pH, about 4.85 to 5.13 across six coffees. Hot coffee did have higher titratable acidity, meaning more total acid compounds. That may be why cold brew tastes less sharp, even though it isn't much less acidic by pH.

The researchers, Niny Rao and Megan Fuller, brewed the same six coffees both ways. Hot brews ranged from pH 4.85 to 5.10 and cold brews from 4.96 to 5.13. They concluded that pH alone is a poor way to describe coffee's acid chemistry, since many different acids add to how sour or bright a cup tastes.

The same study found hot coffee had higher antioxidant activity than cold brew. If you drink cold brew because you've heard it is gentler on the stomach, the research doesn't settle that question. If you have reflux or another digestive condition, a doctor is the right person to ask about coffee.

How do cold brew and iced coffee taste different?

Cold brew usually tastes smooth, heavy and low in bite, with chocolate, nut and caramel flavors in front. Iced coffee tastes livelier and more aromatic, with more citrus, berry and floral notes coming through. Light, fruity coffees tend to shine as iced coffee, while chocolatey medium and dark roasts make easy cold brew.

Hot water pulls out aromatic compounds and acids quickly, which is why iced coffee keeps the brightness of the hot cup. Cold water extracts more gently, so the drink is rounder but can taste flat with delicate light roasts.

Our own data supports matching beans to method. In our coffee by the numbers report (Lesson 05), 96% of light roasts list fruit notes, compared with 42% of dark roasts. If you want fruit in a cold drink, a light roast brewed hot over ice keeps it best. If you want chocolate and low bite, a medium or dark roast cold brew is the safer bet.

Which should you make at home?

Make cold brew if you want a smooth, chocolatey drink ready in the fridge every morning and don't mind planning a day ahead. Make iced coffee if you want a cold cup right now, like bright, fruity flavors, or want to use the brewer you already own. Both are easy and need no special equipment.

You can also keep both on hand. A jar of cold brew concentrate for busy mornings and a bag of light roast for weekend iced pour-overs covers most moods.

Coffees to try for cold brew and iced coffee

We picked coffees from our catalog that suit each method. For cold brew, look for chocolate, caramel and brown sugar notes. For iced coffee, look for fruit and floral notes. Tasting notes below are the roasters' own, and you can find more in our full coffee list.

Coffee Bros. Cold Brew Coffee Blend

A medium roast, natural process blend of Brazil and Ethiopia built for cold brew. The roaster lists dark chocolate, berry and brown sugar. It suits anyone who wants a cold brew that's chocolatey with a touch of fruit.

Hula Daddy Kona Coffee Kona Cold Brew

Kona coffee from Hawaii, sold coarse ground for cold brew. The roaster lists smooth, sweet and mellow. A good fit if you don't own a grinder and want a gentle, easy-drinking batch.

Coffee Bros. Dark Roast Coffee

A dark roast blend of Brazil and Indonesia, natural and wet-hulled. The roaster lists dark chocolate, creamy caramel and maple syrup. It makes a rich cold brew concentrate for drinks with milk.

Peace Coffee Birchwood Breakfast Blend

A medium roast from Peru and Honduras. The roaster lists bittersweet chocolate, honey and cedar. It works as an everyday cold brew or as a mellow iced coffee.

Coffee Bros. Costa Rica – Las Lajas Natural

A medium roast, natural process single origin from Alajuela, Costa Rica. The roaster lists berry, cocoa and toffee. Its mix of fruit and chocolate makes it a solid choice for either method.

Onyx Coffee Lab Tropical Weather

An Ethiopian coffee with natural and washed lots. The roaster lists floral, berries, plum and sweet tea. Brew it hot over ice to keep those fruit and floral notes.

Black & White Coffee Roasters Elto Bare – Natural

A natural process coffee from Sidama, Ethiopia. The roaster lists citrus, stone fruit, raspberry, milk chocolate and peach iced tea. It suits iced coffee fans who want a cup that tastes like summer fruit.

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