What Is Cold Brew Coffee and How Is It Made?

Cold brew coffee is made by extracting coffee with room-temperature or near-0°C water for the entire coffee production process. If hot water touches the grounds at any point, the drink is iced coffee, not cold brew, no matter how it is served. Cold brew splits into two methods: immersion, where grounds soak fully in water, and ice drip, where chilled water drips slowly through the bed.

Bean choice shapes the result. Honduras Sherry beans were used to demonstrate ice drip parameters, and the article also covers shelf life, since cold brew keeps longer than hot-brewed coffee. Iced pour-over and iced Americano are often confused with cold brew, but the extraction water temperature is the deciding factor, not the serving temperature.

On a scorching summer day, a glass of cold brew coffee is almost every coffee lover's first choice for beating the heat. But many people's understanding of cold brew coffee still stops at the level of "iced coffee," and some even confuse iced pour-over and iced Americano with cold brew. In fact, the core of cold brew coffee lies in using low-temperature water throughout the entire extraction process, and depending on the method, it can be further divided into two major categories: cold brew (immersion) and ice drip. This article will start from the definition, sort out the essential differences between cold brew and iced coffee, analyze the types of coffee beans suitable for making cold brew, and use Honduras Sherry beans as an example to introduce in detail Front Street Coffee's ice drip production parameters and process. Finally, it will answer the question of cold brew coffee's shelf life, helping you gain a comprehensive understanding of cold brew coffee.

Cold brew coffee is one of the indispensable choices for enjoying coffee on a hot summer day. Faced with the densely packed coffee varieties on Front Street Coffee's blackboard, knowledge of origins is instantly tossed to the back of your mind, leaving you unsure which one to choose. This time, let Front Street systematically explain everything about cold brew coffee.

What is cold brew coffee?

The brewing logic of cold brew coffee is completely different from that of regular hot coffee. Literally speaking, cold brew means using lower-temperature water to extract coffee. However, since iced pour-over coffee and iced Americano are also served in chilled form, Front Street has encountered quite a few friends who mistake them for cold brew coffee.

To accurately determine whether a cup of coffee qualifies as cold brew, the key is the water temperature used during the extraction stage. Cold brew coffee typically uses room-temperature or even near-0°C low-temperature water to complete the extraction. In other words, whether it's an iced Americano or an iced pour-over, even if it's ultimately served cold, as long as hot water has come into contact with the coffee grounds during extraction, it cannot be classified as cold brew.

Based on differences in production methods, cold brew coffee can be broadly divided into two categories: one is cold brew (immersion) coffee, where coffee grounds are fully submerged in low-temperature water and extracted through prolonged soaking; the other is ice drip coffee, where ice water is dripped drop by drop onto the coffee grounds for extraction.

At Front Street Coffee's stores, limited by equipment conditions, the cold brew coffee currently offered by Front Street Coffee is only available as ice drip coffee.

The key word for cold brew coffee is: low enough temperature. First, we need to clarify a concept — coffee beans contain about 30% soluble substances, and the essence of brewing is simply extracting the portion of these substances that present better flavors. The higher the water temperature, the faster various soluble substances are released: acidic substances move the fastest, sweet substances are next, and bitter substances are the slowest. At the same time, rising temperatures also increase the total amount of these flavor substances.

Conversely, when the water temperature is very low, to extract a sufficient amount of flavor substances, the extraction time must be extended. This also explains why ordering ice drip coffee made with a specific bean at Front Street stores requires booking two days in advance.

What coffee beans are suitable for making cold brew coffee?

Because the water temperature is relatively low during the cold brew process, the release rate of flavor substances slows down noticeably after the coffee grounds come into contact with water, and the extraction amount of some larger-molecular-weight bitter substances decreases accordingly, making the coffee's sweet and sour profile more prominent.

Therefore, Front Street recommends choosing coffee beans with a lighter roast level and excellent acidity, such as Kenya, or beans with distinct and unique flavors, such as Honduras Sherry.

Front Street Coffee's process of using Honduras Sherry coffee beans to make ice drip coffee

Below, Front Street will use Honduras Sherry coffee beans as an example to demonstrate the cold brew coffee production process. First, let's get to know this bean.

Honduras Sherry coffee beans are processed using a method of refined washing plus Sherry whiskey barrel fermentation: cleaned parchment beans are placed into Sherry whiskey barrels and fermented at low temperature for 30 to 40 days, allowing the aromatic substances in the barrels to fully penetrate the green coffee beans. Afterward, they are evenly spread out in a cool, shaded area to dry, preventing the whiskey aroma substances from decomposing into unpleasant whiskey sourness due to excessively high temperatures from direct sunlight.

In the world of whiskey, malt must undergo germination, drying, grinding, mashing, and fermentation before the finally distilled liquid is placed into barrels for long-term maturation. In whiskey flavor, 75% comes from the wooden barrels used for maturation. Barrels made of different materials and previously holding different liquids produce different maturation effects. Among the many types of whiskey, Sherry cask whiskey has won the favor of a large number of whiskey connoisseurs and beginners alike with its rich, sweet flavor. Front Street's Honduras Sherry coffee beans are precisely fermented at low temperature using Sherry whiskey barrels, continuing to a certain extent the sweet characteristics of Sherry whiskey.

When setting the roasting curve, in order to preserve the gentle acidity of Central American beans, Front Street roasts Honduras Sherry coffee beans to a medium level.

Front Street Coffee cupped the roasted Honduras Sherry and tasted rich vanilla and cream flavors, gentle berry acidity, and after the berry acidity faded, a clear oak barrel aroma emerged.

Coffee dose: 60 grams

Coffee-to-water ratio: 1:10

Water temperature: 0°C——4°C

Time: 6——8 hours

Grind size: 85% passing rate on China No. 20 standard sieve

Place 60 grams of coffee grounds into the coffee powder cup, ultimately extracting 600 milliliters of coffee liquid, with a cold brew coffee water-to-coffee ratio of 1:10. Regarding grind size, since the water temperature contacting the coffee grounds is lower than that of regular pour-over, choose a slightly finer setting than pour-over. Measured by a No. 20 sieve, the passing rate is approximately 85%. The mixing ratio of ice to water is roughly 1:1, and the throttle valve controls the flow rate at 7 drops per 10 seconds. At the same time, place a pre-moistened filter paper on the coffee bed to make the extraction more even. The entire extraction process lasts approximately 6——8 hours. After extraction is complete, bottle the coffee liquid and refrigerate it for 12 hours before drinking.

After a night of fermentation, the ice drip coffee made with Sherry coffee beans presents a distinct berry acidity, along with the rich sweetness of chocolate, nuts, and dried fruit found in Sherry whiskey. The mouthfeel is full-bodied, accompanied by fermented notes.

How long can cold brew coffee be stored at most?

Cold brew coffee takes a long time to make, so some friends prefer to make a larger batch at once and store it for later use. The question "How long can cold brew coffee be stored?" has therefore troubled quite a few people.

Front Street recommends that finished cold brew coffee should be placed in a sealable container and stored in the refrigerator at low temperature.

From the moment cold brew coffee is sealed and stored after extraction is complete, the coffee liquid begins to ferment. As time passes, the fermented flavor becomes increasingly pronounced, eventually producing a spoilage taste. Front Street Coffee once kept records: by the fifth day of refrigeration, the cold brew coffee's flavor had already weakened, replaced by a heavy fermented sensation. For safety reasons, Front Street recommends drinking cold brew coffee within one week after extraction is complete.

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