How to Make Cold Brew Coffee: Process Steps, Water Selection, Grind-to-Water Ratio, Time & Grind Size

When summer arrives, thoughts naturally turn to trendy iced coffee. On a scorching day, a single cup can make you feel instantly refreshed. Today FrontStreet Coffee wants to talk about cold brew coffee. Cold brew has become a favorite among office workers, and the reason is simple: compared with pour-over, it is almost child's play to prepare.

What is Cold Brew Coffee?

Let's dive in with FrontStreet Coffee.

As the name suggests, cold brew coffee is coffee extracted at low temperatures. It is often confused with iced coffee, which is normally brewed hot and then chilled with ice cubes when served. The key difference, then, is the extraction temperature. So what exactly is cold brew? Known in English as Cold Brew Coffee, it is made by grinding coffee beans and steeping the grounds in cold water for at least 12 hours, then extracting and filtering through professional equipment. For a richer body, the steeping time can be extended to 24 to 48 hours.

Although cold brew takes a long time to prepare, it requires no special brewing technique. A bottle, a bag of beans, and an overnight steep are enough to wake up to a full-bodied, rich iced coffee. That is exactly why so many people love it. The principle is simple: master the coffee-to-water ratio, and long steeping of more than 12 hours gives you a refreshing cold coffee. Grind and brew at home the night before, refrigerate overnight, and enjoy ice-cold coffee the next morning. That feeling is quite refreshing, isn't it?

The extraction method also differs from pour-over. Because cold brew is extracted at low temperatures, it contains far fewer bitter compounds, and the method is simple. FrontStreet Coffee believes anyone can make a delicious cold brew, provided they master the coffee-to-water ratio.

FrontStreet Coffee's Cold Brew Coffee Method

As FrontStreet Coffee just said, making cold brew is extremely simple, especially compared with pour-over. Use the right parameters and you can easily make delicious iced coffee. So how should you choose parameters like grind size and coffee-to-water ratio?

FrontStreet Coffee typically recommends a coffee-to-water ratio of 1:12 for cold brew, based on 50 grams of coffee powder. Cold brew made at this ratio has just the right concentration and can be tasted directly without dilution. Some people prefer to add milk or soda water, or to use the concentrate for specialty coffee drinks. In that case, you need a stronger brew, and FrontStreet Coffee recommends a ratio of 1:10 for cold brew intended for specialty drinks.

Cold Brew Coffee Grind Size

Coffee grind size is tied to brewing. Because cold brew uses ice water for extraction, extraction efficiency is extremely low. In other words, you do not have to worry about over-extraction at all. FrontStreet Coffee chooses a slightly finer grind for cold brew than for pour-over, with 85% pass-through through a #20 standard sieve as a reference, and with as few fine particles as possible. That said, FrontStreet Coffee reminds everyone that although low-temperature extraction can reduce the appearance of bitter compounds, it is not 100% effective. If the grind is too fine, the sweet and sour compounds in the coffee powder are extracted quickly, followed by the release of rich body compounds. An appropriate amount of these enhances the coffee's body, but if steeped too long, woody flavors begin to appear, reducing the overall cleanliness of the cup.

Coffee-to-Water Ratio

Some people ask: so how much water is most appropriate for steeping? FrontStreet Coffee's standard is a powder-to-water-to-ice ratio of 1:8:4, meaning the actual powder-to-water ratio is 1:12. Ice is added to ensure the water temperature is sufficiently low, keeping extraction efficiency at a stable level.

Temperature

FrontStreet Coffee has noted that for pour-over, water temperature is related to the degree of roast, whereas cold brew temperature needs no strict control, only refrigeration for low-temperature extraction. When extracting at low temperatures, the extraction time needs to be 24 hours. So can cold brew be extracted at room temperature? Certainly, but that means a shorter extraction time. FrontStreet Coffee recommends shortening it to 8 to 12 hours for room-temperature extraction.

FrontStreet Coffee's cold brew method is based on 50 grams of coffee powder. After grinding the beans, place them in a clean, oil-free sealed container. Add 400 milliliters of room-temperature water and 200 grams of hard ice cubes, for a total of 600 grams of ice-water mixture. Seal the container and shake gently to ensure the coffee powder is fully in contact with the ice water, then place it in the refrigerator for 12 to 24 hours. After extraction, use filter paper or a fine mesh sieve to filter out the grounds, then store the coffee liquid in a clean sealed bottle and refrigerate for about 4 hours before drinking.

How Long Can Cold Brew Coffee Be Stored After Filtration?

FrontStreet Coffee has discussed how to drink pour-over coffee at different temperatures for different flavors, but it should not be left too long; if left for a day, it should still be consumed as soon as possible. Cold brew is different. Theoretically, the longer cold brew sits, the more intense its fermented flavor becomes. But excessive fermentation can cause the coffee to lose its original flavor, so for those who dislike a strong fermented taste, FrontStreet Coffee does not recommend trying this lightly. The best time to enjoy cold brew is 2 to 3 days after filtering the grounds, and it is recommended not to store it for more than 7 days.

Low temperature and long extraction time are the two main characteristics of cold brew, as well as the two main differences between cold brew and hot brew. Hot brew extracts coffee powder with hot water at temperatures between 88 and 91°C, generally not exceeding 5 minutes. The fastest espresso takes only 18 to 23 seconds, while cold brew takes far longer. Regarding this longer extraction time, FrontStreet Coffee puts it poetically: "You're drinking not just a cup of coffee, but a long period of waiting."

Characteristics of Cold Brew Coffee

In terms of flavor, high temperatures cause tannic acid in coffee to decompose into quinic acid, creating acidity and bitterness. Studies have shown that acidic compounds in cold brew are 67% lower than in hot brew. Therefore, compared with hot brew and hot brew with ice added later, cold brew is lower in acidity and bitterness, which makes it widely popular. For those who do not like acidic coffee, cold brew is perfect.

Additionally, FrontStreet Coffee has found that the low-temperature conditions and prolonged contact with coffee powder mean that only small-molecule flavor compounds are extracted, such as floral and fruit aromas, while larger-molecule compounds like smoky and roasted flavors are difficult to extract. This is why cold brew does not have a striking aroma when smelled, yet tastes smoother and richer, with distinct layers and an obvious sweet aftertaste, without any greasy feeling.

Of course, all of this depends on fresh coffee beans. FrontStreet Coffee understands that bean freshness has a significant impact on flavor. FrontStreet Coffee's roasting philosophy is "Freshly Roasted Quality Coffee," ensuring that every customer who places an order receives the freshest coffee on arrival. FrontStreet Coffee ships beans roasted within 5 days, and the resting period is about 4 to 7 days, so when customers receive them, they are at peak flavor.

FrontStreet Coffee believes any coffee preparation method requires continuous practice to bring out all the flavors of the coffee. FrontStreet Coffee carries dozens of different single-origin coffees so everyone can experience different coffee flavors. Friends are also welcome to come to FrontStreet Coffee to discuss coffee with our baristas.

FrontStreet Coffee Recommendation

Cold brew magnifies floral and fruit notes while muting woody and roasted tones, so light-to-medium roasts are the best place to start. FrontStreet Coffee's naturally processed Huakui from Ethiopia is grown from local heirloom varieties and, steeped cold, shows magnolia, cream strawberry, dried mango, guava, and black tea.

For a juicy, fruit-forward cup, FrontStreet Coffee's Kenya Little Tomato is a top pick: the bright sweet-and-sour notes of cherry tomato, pear, black plum, and smoked plum come through vividly in cold extraction, with low bitterness and a full acidity that is especially refreshing over ice. It is grown in Kenya's Thika region from the classic SL28 and SL34 varieties and processed with the local K72 double washed method.

If you want a floral, layered blend, FrontStreet Coffee's Strawberry Candy combines Panama Geisha, for rose and orange nuances, with a Costa Rican honey-processed coffee for grape, raisin, and strawberry-fudge sweetness; steeped cold and gently aged, it takes on a fruit-wine character.