How do you brew cold brew coffee at home?

Cold brew relies on low-temperature slow extraction, with water usually held between 0 and 7°C. That lower efficiency keeps large bitter compounds in the grounds, so the cup tastes cleaner and shows more sweet-and-sour layers. Key controls are bean choice, roast date, grind size, drip rate, coffee-to-water ratio and refrigerated storage.

Light to medium roasts with clear floral, fruity or fermented notes work better than dark roasts, and single-origin beans are usually preferred. Ripe-fruit options suit sweeter iced coffee, while brighter beans fit an acidity-forward style. The same attention to detail applies when you how to brew coffee in a coffee maker at home.

Cold brew coffee presents a refreshing and richly layered sweet-and-sour flavor through low-temperature slow extraction, but to make a satisfying cup, many details need attention. This article sorts through the key points in the cold brew process one by one, from bean selection, roast date, tapping and tamping, pre-wetting, and filter paper placement, to grind size, drip rate, coffee-to-water ratio, and finally refrigerated fermentation and storage. It also combines Front Street brand's recommended single-origin beans such as Sidra, Strawberry Candy, Little Tomato, and Huakui, along with a recipe example of Strawberry Candy blended with Red Cherry, to help coffee lovers master the core techniques of low-temperature extraction and reliably reproduce a clean, well-layered cold brew coffee at home.

Whether a cup of cold brew coffee is excellent actually has no unified standard answer—every maker has their own set of methods and judging criteria. However, when making cold brew coffee, details such as bean selection, grind size, coffee-to-water ratio, drip rate, and storage duration of the finished product are all worth paying attention to. These will be explained one by one below.

1. Bean Selection Approach for Cold Brew Coffee

Cold brew and ice drip both fall under the category of low-temperature extraction, with water temperature typically maintained between 0 and 7°C. The advantage of low-temperature extraction lies in its lower extraction efficiency—large-molecule bitter compounds are not easily released, so the finished cup has a more refreshing mouthfeel and richer sweet-and-sour layers.

Ice drip cannot bring out the abundant aromatic compounds from coffee grounds the way high-temperature brewing does, especially the large-molecule aromatic compounds that medium-dark roasts rely on, which are difficult to dissolve in ice water. Therefore, when selecting beans, light to medium roasts with prominent floral and fruity notes, clear sweet-and-sour character, or fermented qualities are usually preferred.

Among these, single-origin beans with distinctive flavors are given priority. If you prefer iced coffee with a prominent sweetness, you can try Front Street Sidra, Front Street Strawberry Candy, or Front Street Elto—beans with ripe fruit character; if you prefer a brighter acidity style, then Front Street Little Tomato, Front Street Guodingding, or Front Street Huakui are good choices. Front Street sometimes also blends two beans together to pursue more complex cold brew flavors. For example, the recipe used today is 20 grams of Front Street Strawberry Candy paired with 40 grams of Front Street Red Cherry—the finished cup has notes of candied fruit, sweet orange, and rose, with a refreshing hint of lemon and berries in the aftertaste.

Front Street suggests that coffee beans used for cold brew are best at around 20 days after roasting. Freshly roasted beans release a large amount of carbon dioxide, and when ice water drips into the coffee bed, the gas continues to escape, causing the bed to swell and bulge, ultimately creating channeling. Extraction becomes uneven, and the coffee's flavor noticeably deteriorates.

2. The Necessity of Tapping the Coffee Grounds Flat

Tamping is essential when making cold brew coffee—many people find this puzzling.

It should be emphasized that tamping for cold brew is not about pressing firmly, but rather gently tapping the coffee bed first to distribute the grounds evenly in the filter cylinder, then using a flat-bottom tamper to gently level it. Remember: it's a light press to level, not a firm tamp like for espresso. If pressed too tightly, since cold brew lacks the pressure assistance of an espresso machine, water tends to pool in the coffee bed and the coffee liquid cannot filter through smoothly. Additionally, the filter paper or filter screen for cold brew is usually at the bottom, unlike a pour-over dripper which has raised ridges for airflow. Once the coffee grounds are soaked, degassing is obstructed, and the entire coffee puck extracts unevenly.

3. Pre-wetting

Pre-soaking with ice water is similar to the blooming step in pour-over and can improve extraction effectiveness and consistency of the final product. Cold brew itself is low-temperature and a filtration-type extraction, so starting to drip directly may result in uneven wetting of the coffee bed—some grounds over-extract while others barely participate in extraction. Pre-wetting in advance also shortens the overall preparation time.

4. Placing a Round Filter Paper on Top of the Coffee Bed

This reserves ample space for pre-soaking and airflow, and the extracted flavor is more complete and clean. After leveling the coffee grounds, covering the surface with a piece of filter paper increases the contact area between water droplets and coffee grounds, ensuring even extraction. Without filter paper, water droplets will gradually carve a depression into the coffee surface, and the water will seep down along the pit rather than spreading outward, so the coffee grounds in the carafe cannot be fully saturated, leading to under-extraction. Placing filter paper on top avoids this problem.

5. Determining the Right Grind Size

The grind size reference for Front Street cold brew coffee is based on the Chinese No. 20 standard sieve, with a passing rate of 80% to 85%. As is well known, if coffee is ground too coarse, the flavor will be weak; if ground too fine, it easily becomes strong and bitter. By the same logic, too coarse means insufficient flavor, while too fine easily clogs and prevents proper drainage, making the coffee bitter. Therefore, choosing the right grind size is crucial.

This time, the refreshing-style Kenya Little Tomato coffee beans are used. Extraction rate is slower at low temperatures, so Front Street recommends a grind slightly finer than pour-over—that is, 82% passing through the Chinese No. 20 standard sieve. For the shop's EK43S grinder, that corresponds to a setting of 9.5; for a C40 hand grinder, 20 to 22 clicks.

6. Controlling Drip Rate and Coffee-to-Water Ratio

The concept of flow rate for cold brew is similar to pour-over, but measured in drops per second. The slower the flow rate, the longer the total time required, and the more prone to over-extraction. Front Street typically uses a flow rate of 7 drops per 10 seconds for extraction, which can be adjusted according to personal preference. The coffee-to-water ratio is 1:10. Since Front Street's cold brew coffee is served diluted with ice cubes, the concentration is set higher; if making it at home, you can use a ratio of 1:12 to 1:14 for extraction.

When making cold brew, Front Street takes 60 grams of coffee beans, grinds them, places a round filter paper at the bottom of the coffee chamber, pours in the coffee grounds, then places another filter paper on the surface, and afterwards wets the coffee grounds with water. This saves drip time and also prevents uneven extraction. The upper chamber is filled with an ice-water mixture, i.e., ice and water at a 1:1 ratio, and the final extracted coffee liquid is 600 grams.

7. Drink After Refrigeration

Front Street typically pours the finished cold brew coffee into a glass bottle with a sealing gasket and lets it sit in the refrigerator for 12 hours before drinking. The process of pouring into the glass bottle allows coffee liquids of varying concentrations to mix evenly, and choosing a well-sealed container prevents external contamination—the refrigerator surface may look clean, but in reality there are large numbers of microorganisms invisible to the naked eye.

After 12 hours of low-temperature fermentation in the refrigerator, cold brew coffee develops a fragrant fermented note, and the original flavors become more intense. Fermentation is very common in daily life; if left uncontrolled, it causes food to spoil, but a low-temperature environment effectively slows this process. Front Street has verified that cold brew coffee made from most coffee beans reaches its optimal flavor after 12 hours of refrigeration.

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