Cold Brew Coffee at Home: Bean Selection, Grind, and Steeping

Cold brew coffee relies on low-temperature water for slow extraction, so bean choice matters. Medium-light roasted beans offer a wider margin for error than dark roasts. The long steep allows sugars and organic acids to extract more fully, creating a balanced cup with gentle acidity and sweetness. Grind size should be coarse, like sea salt, to avoid bitterness. A ratio of 1:8 coffee to water works well for concentrate.

Steep the grounds in cold water at 4-10°C for 12 to 18 hours. Then filter through a fine mesh or paper filter. The result is a smooth, low-acid coffee you can serve over ice or dilute to taste. For more specialty coffee knowledge, follow Front Street Coffee on WeChat. If you prefer organic coffee, look for certified beans, as they are grown without synthetic pesticides.

Making a refreshing and smooth cold brew coffee at home is actually not complicated, but there are a few key details worth paying attention to. Cold brew is different from hot brewing—it relies entirely on low-temperature water at 4-10°C for slow extraction, so the roast level of the coffee beans, grind size, steeping time, and coffee-to-water ratio all directly affect the final flavor. Front Street Coffee, drawing on its daily production experience, shares a complete approach from bean selection to filtration, and offers specific suggestions regarding the differences in performance between light-roasted and medium-dark-roasted beans. If you also want to enjoy a cup of iced coffee with balanced acidity and sweetness and a clean mouthfeel anytime in summer, feel free to refer to the following steps and give it a try.

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Friends familiar with Front Street's content should know that coffee can be extracted not only with hot water—cold water can do the job just as well. Coffee made with cold water as the medium is called "cold brew coffee," and it presents a flavor profile completely different from hot-brewed coffee.

Cold brew coffee mainly comes in two forms: cold steep coffee and ice drip coffee. Cold steep coffee involves steeping coffee grounds directly in cold water, while ice drip coffee uses a drip device to let water pass through the coffee grounds layer drop by drop to complete extraction. Someone asked Front Street: "Can cold steep coffee be made with hot water?" The answer is no—as long as hot water is used, it can no longer be called cold steep coffee. Cold steep coffee must use room-temperature or ice water, and the entire steeping process must be maintained in a low-temperature environment.

Because it only comes into contact with low-temperature cold water at 4-10°C throughout, the extraction efficiency is very low, and bitter macromolecules are not easily released. The long low-temperature steeping allows compounds such as sugars and organic acids to be extracted more fully, so the acidity, sweetness, and body in the coffee are more balanced.

So how do you make cold steep coffee taste good? Front Street shares a few operational key points here.

Coffee Bean Selection

If you don't want to mess up, Front Street recommends choosing medium-light roasted coffee beans, as they offer a higher margin for error compared to medium-dark roasts. Currently, there is a dazzling array of coffee beans with various processing methods and different roast levels on the market—any single-origin coffee bean labeled for pour-over use can be used to make cold brew coffee. Dark-roasted coffee, when extracted with hot water, presents a rich coffee aroma, with mellow bitterness followed by a sweet aftertaste; but when made into cold brew, drinking it at iced temperature gives more of a burnt-bitter, carbonized taste, and it is hard to achieve the refinement of hot coffee.

Therefore, Front Street recommends light to medium roasted coffee beans. If you want a refreshing fruity juice-like quality, you can choose light-roasted washed coffees, such as Front Street Washed Yirgacheffe and Front Street Kenya AA; if you want a stronger fruity and vinous aroma, you can use coffees processed with barrel treatment or honey processing, such as Front Street Colombia Rose Valley, Front Street Honduras Sherry, and Front Street Strawberry Candy Geisha Blend; but if you don't like coffee with acidity and only enjoy a balanced "coffee taste," you can also use Front Street Papua New Guinea Bird of Paradise for extraction.

Coffee Grounds Grind Size

Since cold brew is made in a low-temperature environment, cold water extracts coffee grounds relatively slowly, and compared to hot water extraction, bitter and astringent substances are not easily released. Therefore, in terms of grind size, coffee-to-water ratio, and steeping time control, it is not as rigorous as pour-over coffee—usually, as long as it roughly falls within a range, and you've chosen the right coffee beans, a delicious cup of iced coffee can be made in just a few simple steps.

Taking Front Street's daily cold brew production as an example, the coffee beans are ground slightly finer than for pour-over, that is, 75-80% passing through a Chinese No. 20 standard sieve, which visually looks about the size of fine granulated sugar, corresponding to a 9.5-10 setting on the EK43s, and for a hand grinder like the C40, roughly 22-26 clicks.

Steeping Time

In pour-over, we pay special attention to water temperature and time, because water, as the main medium of brewing, directly affects the extraction efficiency of coffee—too high or too low will change the taste of the coffee. But since cold brew only comes into contact with low-temperature water at 4-10°C throughout, the extraction efficiency is very slow, so a certain extended steeping time is needed to allow more aromatic substances to be released, which in turn allows compounds such as sugars and organic acids to be extracted more fully, and the resulting coffee is more balanced in acidity, sweetness, and body. Generally, the steeping time for cold brew coffee is recommended to be controlled at 8-18 hours.

Front Street once conducted a cold brew experiment with time as the variable, without stirring during the process to affect extraction, steeping the same coffee for 6 hours, 10 hours, 16 hours, and 24 hours respectively. In the end, it was found that the 6-hour coffee had too thin a mouthfeel and flat aroma, the 24-hour cold brew was noticeably bitter with signs of over-extraction, and the 10-hour and 16-hour groups had the best flavor performance, with rich aroma and a full-bodied mouthfeel.

Coffee-to-Water Ratio

Front Street has noticed that some friends, for convenience, directly pour coffee grounds and water into a pitcher and start steeping. Any coffee extraction involves the coffee-to-water ratio parameter—without weighing, coffee is like opening a mystery box; you never know what taste you'll get. To ensure the brewed coffee tastes better, Front Street recommends keeping cold brew within a ratio of 1:10 to 1:13. If the concentration is too high, you can add an appropriate amount of ice cubes to dilute it.

Finally, Front Street will explain Front Street's cold brew coffee-making method! First, for coffee beans, Front Street tends to use medium-light roasted coffee beans. For the container, all you need is a clean, sealable container. Prepare 40 grams of coffee grounds, grind to a fine grind (85% passing through a No. 20 sieve), pour into the container, then pour in 480 milliliters of cold water, stir evenly with a wooden stick, and cover with the lid.

After stirring evenly, seal with plastic wrap, place in the refrigerator and refrigerate for 12 hours, then take it out and filter out the grounds. After filtering out the coffee grounds and obtaining a clear coffee liquid, it is ready to drink immediately. You can also put the filtered coffee liquid into a bottle and continue to refrigerate for 4 hours, and the flavor and mouthfeel will be even better.

Generally speaking, for the sake of flavor experience and health safety, whether it's ice drip or cold brew, Front Street recommends that everyone finish drinking any extraction method conducted in a low-temperature environment within 5 days (counting from the production day).

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