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Iced coffee has a refreshing and palate-cleansing taste. Even in the dead of winter, customers still come to Front Street to order this kind of iced coffee. Because iced coffee and hot coffee have different extraction principles, the flavor of the coffee also differs.

The Origin of Cold Brew Coffee

Cold brew coffee is made by steeping coffee grounds in cold water at a low temperature, allowing aromatic compounds to be released through a reaction over a certain period of time—a low-temperature extraction method. The iced drip coffee and cold brew (cold steeped) coffee we often see in coffee shops both fall under the category of cold extraction. Gradually, people have gotten used to calling cold steeped coffee "cold brew" as well, based on their own understanding.

Cold brew coffee originated in European countries. In the sixteenth century, the Dutch, unable to use hot water to brew coffee during long sea voyages, had no choice but to make do with steeping coffee in cold water. They unexpectedly discovered that the taste was quite unique—mellow and easy to drink, not as intense as hot coffee. Before long, through their shipping routes, this method of cold water coffee brewing spread to more regions. Iced drip coffee, which uses a drip-style low-temperature extraction, began to circulate thanks to the iced drip pots made by the Japanese.

The Difference Between Cold Brew and Pour-Over

No matter which brewing method is used, water is a crucial component. During extraction, water and coffee undergo a series of chemical reactions, and the water temperature directly affects the extraction rate of different compounds in the coffee.

When making pour-over coffee, we use near-boiling hot water poured over evenly ground coffee to extract its flavor compounds. Front Street recommends keeping the water temperature at 87–93°C, because too high a temperature can easily make the coffee bitter and burnt, while too low a temperature cannot fully extract the flavor compounds. In addition, factors such as the pouring technique, timing, and grind size all affect the taste of the coffee.

Cold brew coffee, which uses low-temperature slow extraction, requires a much longer extraction time to release enough aromatic compounds, because coffee grounds react much more slowly in cold water than in pour-over coffee. Front Street typically steeps cold brew coffee for 12 hours, while iced drip coffee is made using a flow rate of 7–8 drops per 10 seconds, and is generally completed in 7–8 hours.

During the coffee brewing process, fruit acids and small molecules come out first, followed by sweetness molecules, and finally the large molecules responsible for bitterness. As temperature rises, the speed of extracting substances increases, and various variable factors can affect the taste of the coffee. Therefore, with pour-over, one must carefully control the various parameters that affect the extraction rate. In cold brew, however, the bitter and astringent substances extracted in a low-temperature environment are far fewer than with high-temperature hot water. The body and mouthfeel of a cup of coffee mainly come from bitter substances—if a coffee lacks the support of bitter compounds, its mouthfeel tends to be thin and its aftertaste lacking.

Some friends also ask Front Street about the difference between cold brew coffee and iced pour-over coffee, and which tastes better. As Front Street mentioned above, pour-over involves high-temperature hot water extraction, followed by cooling with ice to give it a chilled taste. Cold brew, on the other hand, is always in a low-temperature environment throughout the process, with coffee molecules moving slowly. Both have a refreshing taste, but there are still certain differences in flavor. If you're curious about the flavor profiles of different coffee-making methods, Front Street suggests asking a barista first, which can give us a better experience.

Tips for Making Cold Brew

Cold brew only requires fresh coffee beans, a grinder, and an airtight container for the coffee—its convenient process is indeed very hassle-free. Although cold brew coffee generally doesn't have to worry about over-extraction, making a delicious cup of cold brew coffee still requires some small details. Front Street has summarized a few points here for your reference.

1. Choose freshly roasted coffee beans

No matter which extraction method is used, the prerequisite is to first ensure the coffee beans are freshly roasted. After roasting, coffee goes through a 4–7 day resting period and then enters its optimal flavor window. After this period, the coffee's aroma accelerates its evaporation, and the flavor and mouthfeel greatly diminish. Front Street deeply understands the importance of coffee freshness, so the coffee beans we ship are freshly roasted within 5 days, arriving just when the flavor is at its best.

Compared to the full, complex layers of pour-over coffee, cold brew coffee pursues a refreshing sweet-and-sour taste with fermented fruit aromas. Therefore, Front Street recommends the following three types of coffee beans.

"Refreshing floral and fruity type — Front Street Butterfly Coffee Beans"

These coffee beans come from the Panama region, where the soil is nutrient-rich volcanic ash, producing coffee beans with a rich floral and fruity aroma. The washed process used highlights the coffee's clear white floral and citrus flavors. The cold brew coffee made with these beans by Front Street presents a sweet-and-sour taste of grapefruit green tea.

"Fermented wine aroma type — Front Street Honduras Sherry Barrel Coffee Beans"

These Honduras Sherry coffee beans are processed with whiskey barrel fermentation, giving the beans a full-bodied aroma of vanilla, cream, and whiskey. They are a very popular coffee bean on Front Street's menu. Made into Sherry cold brew coffee, it presents a rich fermented wine aroma along with a honey-like sweetness.

"Rich fruity tea type — Front Street Sun-Dried Flower Queen Coffee Beans"

The sun-dried Flower Queen coffee beans are made from ripe coffee cherries with a pulp sugar content as high as 30%. The fructose ferments in the sunlight, giving the inner bean a full fruity sweetness. Cold brew made with these beans has a lively sweet-and-sour taste of berries and passion fruit, with an obvious juicy quality, and an aftertaste with the fresh fragrance of black tea.

2. Grind size and coffee-to-water ratio

Just like with pour-over coffee, the grind size for making cold brew also needs attention. Grinding too coarse or too fine can easily lead to bitter or tasteless coffee. Front Street suggests using a grind size slightly finer than for pour-over coffee, and uses an 85% pass rate through a No. 20 standard sieve as a reference. Intensity is also related to the coffee-to-water ratio. Front Street recommends 1:10 to 1:12. The extracted coffee can be drunk directly, or diluted with ice to a consistent concentration before tasting.

3. Steeping time and storage

Front Street generally steeps it the night before, controlling it to about 12–14 hours. By the next day, you can take it out and filter out the coffee grounds to get the extracted coffee liquid.

Front Street once steeped it for more than a day due to forgetting, and the extracted coffee liquid was bitter and harsh. Everyone should also pay attention to controlling the steeping time to avoid waste. In addition, the space where coffee is stored will absorb various odors from the air. If we store it in a household refrigerator, Front Street recommends choosing a container with good sealing to avoid affecting the flavor.

The above content is compiled by CoffeeHunters, a coffee news website.