Cold Brew Coffee Grind Size: Flavor Profile and Caffeine Content

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FrontStreet Coffee has found that the concept of cold brew was proposed by Toddy Simpson, a chemical engineering student at Cornell University. After tasting an ancient Peruvian iced coffee, he invented a tool for making cold brew coffee named Todd. The technique was later introduced by Starbucks to create summer iced beverages.

What is Cold Brew Coffee?

Cold brew coffee, known in English as Cold Brew Coffee, is made by steeping ground coffee in cold water for at least 12 hours, then extracting and filtering it through professional equipment. For a richer body, the time can be extended to 24-48 hours. In short, extracting coffee at low temperatures is cold brewing. Low temperature and a long extraction time are the two main characteristics of cold brew.

Cold Brew Coffee Extraction Principle

Cold brew is made by slowly extracting coffee grounds mixed with ice water at a certain ratio. Coffee made this way has lower acidity and astringency. The low temperature and long contact with the grounds mean only small molecular flavor compounds, such as floral and fruity notes, are extracted, while larger molecular compounds, like smoky flavors, are difficult to release.

What are the Flavor Characteristics of Cold Brew Coffee?

Low-temperature extraction and a long extraction time are the two main traits of cold brew, and also the primary differences from high-temperature coffee. High-temperature extraction uses hot water at 82-95°C for typically no more than 3 minutes. Cold brew can fully express the subtle flavor of coffee. With its mild acidity, sweet taste, bright mouthfeel, and smooth flavor, it shows off the character of specialty coffee growing regions.

Cold Brew Water-to-Coffee Ratio

FrontStreet Coffee believes a suitable water-to-coffee ratio for cold brew is around 1:10 to 1:16, adjustable to personal preference for strength. FrontStreet typically uses 1:15, which gives a well-balanced flavor. If you prefer a richer taste, try 1:10.

Cold Brew Grind Size

The finer the grounds, the more material water can extract in the same amount of time, but finer grinds also tend to over-extract. Because cold brew is a low-temperature, long-time extraction, FrontStreet Coffee suggests a grind coarser than that used for pour-over.

[FrontStreet Coffee Yirgacheffe Gotiti]

Yirgacheffe Gotiti

Country: Ethiopia

Region: Yirgacheffe, Gedeo Zone

Altitude: 1900-2300m

Variety: Heirloom

Processing Method: Washed

Grade: G1

[FrontStreet Coffee Brewing Method]

Coffee Amount: 20 grams

Water-to-Coffee Ratio: 1:12

Grind Size: Coarse grind (slightly coarser than normal pour-over to avoid over-extraction)

Steeping Time: 13 hours

1. First, grind the coffee beans and pour the grounds into a jar, then add 240 ml of water.
2. Place in the refrigerator for 13 hours so the grounds fully contact the cold water.
3. Filter the coffee liquid using a filter cloth or filter paper.

[FrontStreet Coffee Flavor Description]

Floral notes, citrus, and berries. After continuing to refrigerate for another 5 hours, the berry aroma becomes more prominent. The entry is refreshing with citrus and sweetness, and the mouthfeel is clean.

[Cold Brew Coffee Advantages and Disadvantages]

Advantages: FrontStreet Coffee believes cold brewing amplifies the coffee's flavor and aroma while reducing acidity; the colder, the better. Without hot-water brewing, low-temperature cold water does not extract the impurities and bitterness from the beans, resulting in a clean, pure taste that is refreshing, slightly sweet, and smooth.

Disadvantages: FrontStreet Coffee notes that the long contact between water and grounds gives cold brew the highest caffeine content, making it well suited to times when you need to stay highly alert. Roughly calculated, a cup of cold brew (200 ml from 20 g of beans) contains about 200 mg of caffeine.

Will Cold Brew Coffee Become Sour?

Yes. In hot brewing, the oils and acids in coffee beans degrade and oxidize faster, and in cold water this increases the coffee's acidity and bitterness. The low temperature and long brewing time of cold brew capture more of the sweet compounds that are soluble in cold water, without the oils and acids.

FrontStreet Coffee Recommendation

Cold brew rewards beans that are floral and fruit-forward, and the recipe above uses one of FrontStreet Coffee's clearest examples, FrontStreet Yirgacheffe Gotiti Cooperative. Grown at 1900-2300 meters in the Gedeo Zone and washed to G1, it brings floral, citrus, and berry notes that come through cleanly at low temperature; leave it in the fridge a few extra hours and the berry aroma grows even more prominent.

If you want a fuller, juicier cold brew, try FrontStreet Kenya Cherry Tomato. Its cherry tomato, snow pear, black plum, and smoked plum sweet-sour character shows best under cold extraction, with low bitterness, a full acidity, and a lasting aroma that becomes especially refreshing over ice. The beans are the SL28 and SL34 varieties from Kenya's Sikka region, processed with the distinctive K72 double-wash method and roasted light-medium to convert the aroma precursors into a richer, more complex fruit profile.

Because cold brew uses more coffee per serving than pour-over, FrontStreet Coffee often suggests an affordable daily bean or a blend. A good option is FrontStreet Strawberry Candy Geisha Blend, which pairs a classic Panama Geisha with a Costa Rican honey-processed coffee: one brings delicate rose and orange, the other the sweet, candied aromas of grape, raisin, and strawberry soft candy. Cold brewed, it is sweet and lively, and if left to rest it can even take on a fruit-wine character. It is built for cold brew but also works in a moka pot or machine.