When summer arrives, trendy iced coffee comes to mind. Indeed, in this scorching summer, a glass of iced coffee instantly makes you feel refreshed. Today Front Street wants to talk to you about iced coffee, specifically cold brew coffee. Cold brew coffee has become a favorite among office workers—why is that? Front Street believes that the reason cold brew coffee is so popular is mainly because it's extremely simple to make; compared to pour-over coffee, it's like comparing a molehill to a mountain.

Now let Front Street properly tell you all about cold brew coffee!

Since we're calling it cold brew coffee, then as the name suggests, Cold Brew Coffee refers to coffee extracted at low temperatures. It is often confused with iced coffee, which usually refers to coffee that is extracted at high temperatures and then cooled with ice cubes when served. So the first and biggest difference between cold brew coffee and regular iced coffee is the extraction temperature. So what is cold brew coffee? Cold Brew Coffee, as the English name suggests, is made by grinding coffee beans into coffee grounds, soaking them in cold water for generally at least 12 hours, and then extracting and filtering through professional equipment. If you want a fuller body, you can also extend the time to 24-48 hours.

Front Street believes that although cold brew coffee takes a long time to make, it requires no technique whatsoever—one bottle, one bag of beans, one night, and you can wake up to a full-bodied, rich iced coffee. This is also why many people love cold brew coffee. The principle behind making cold brew coffee is very simple: you just need to get the coffee-to-water ratio right and soak for a long time (over 12 hours) to get a glass of refreshingly cool coffee. Grind and brew at home the night before, refrigerate overnight, and the next morning you can drink ice-cold coffee—that feeling is pretty great, right?

Cold brew coffee and pour-over coffee use different extraction methods. Cold brew extracts far fewer bitter compounds at low temperatures, and the method is simple to make. Front Street believes that anyone can make a delicious cold brew coffee—of course, you need to get the coffee-to-water ratio right!

Front Street's method for making cold brew coffee

Front Street just mentioned that the method for making cold brew coffee is very simple, especially compared to pour-over, it's even more straightforward. As long as you use the right parameters, you can easily make a delicious iced coffee. So, how do you choose parameters like grind size and coffee-to-water ratio for making cold brew coffee?

Front Street usually recommends a coffee-to-water ratio of 1:12 for cold brew coffee, based on 50 grams of coffee grounds. This produces a cold brew with just the right concentration that can be enjoyed directly without dilution. Some friends prefer to add milk/soda water or use it for specialty coffee drinks, in which case you need to increase the coffee concentration. Front Street recommends a ratio of 1:10 for cold brew intended for specialty coffee drinks.

Grind size for cold brew coffee

The grind size of coffee is related to brewing. Since cold brew coffee uses ice water for immersion extraction, the extraction efficiency is extremely low. In other words, there's no need to worry about over-extraction at all. Front Street chooses a grind size for cold brew coffee that is slightly finer than pour-over grind, with a reference standard of 85% passing through a No. 20 standard sieve, with as few fines as possible. However, Front Street reminds everyone to note: although low-temperature extraction can reduce the emergence of bitter compounds, it's not 100%. If the grind is too fine, after the sour and sweet substances in the coffee grounds are quickly extracted, the rich and heavy substances will be released. A moderate amount of heavy substances can enhance the coffee's body, but if soaked too long, woody flavors will begin to appear, reducing the overall cleanliness of the coffee.

Coffee-to-water ratio

Some friends might ask: how much water is most suitable for soaking? Front Street's production standard is a ratio of coffee to water to ice of 1:8:4, meaning the actual coffee-to-water ratio is 1:12. Ice is added to ensure the water temperature is low enough and the extraction efficiency remains at a stable level.

Temperature

Front Street has told you before: the water temperature for pour-over coffee is related to the roast level, but the temperature for cold brew coffee doesn't require strict control—you just need to put it in the fridge for low-temperature extraction. When extracting at low temperatures, the extraction time needs to be 24 hours. So can cold brew coffee be extracted at room temperature? Cold brew coffee can certainly be extracted at room temperature, but the corresponding extraction time is shortened. When extracting at room temperature, Front Street Coffee recommends shortening the extraction time to 8 to 12 hours.

Front Street Coffee's cold brew method is based on 50 grams of coffee grounds. After grinding the coffee beans, place them in a clean, oil-free sealed container, add 400 ml of room-temperature water and 200 grams of hard ice cubes (totaling 600 grams of ice-water mixture), cover with a lid and shake gently to ensure the coffee grounds and ice water fully contact, then place in the refrigerator and let sit for 12-24 hours. After extraction, use filter paper or a fine mesh strainer to filter out the coffee grounds, then use a clean sealed bottle to store the coffee liquid and refrigerate for about 4 more hours before drinking.

How long can cold brew coffee be stored after filtering?
Front Street has talked about how to drink pour-over coffee—different temperatures, different flavors—but you can't leave it for too long, say a day, and you still need to drink it as soon as possible. Cold brew coffee is different. Theoretically, the longer cold brew coffee sits, the stronger the fermented flavor becomes. But over-fermentation causes the coffee to lose its original flavors. For those who don't like too strong a fermented taste, Front Street doesn't recommend trying it lightly. The best time to enjoy cold brew coffee is 2-3 days after filtering out the grounds, and the recommended storage time should not exceed 7 days.

Low temperature and long extraction time are the two major characteristics of cold brew coffee, and also the two main differences between cold brew coffee and hot brew coffee. Hot brew coffee extracts coffee grounds with hot water at temperatures between 88-91°C, generally not exceeding 5 minutes. The fastest Espresso takes only 18-23 seconds, while cold brew coffee far exceeds hot brew coffee in terms of time. Regarding the longer extraction time of cold brew coffee, Front Street puts it poetically: "What you're drinking is not just a cup of coffee, but a long wait."

Characteristics of cold brew coffee

In terms of flavor, high temperatures cause the tannic acid in coffee to break down into pyrogallic acid, creating sourness and bitterness. Studies have shown that the acidic substances in cold brew coffee are 67% lower than in hot brew methods. Therefore, compared to hot brew coffee and iced coffee made by adding ice to hot brew, coffee made with the cold brew process has lower acidity and bitterness, and is widely welcomed. For friends who don't like sour coffee, cold brew coffee is perfect!

Additionally, Front Street has found that the low-temperature conditions and prolonged contact with coffee grounds mean that only small-molecule flavor compounds are extracted, such as floral and fruity notes, while larger-molecule flavor compounds like smoky and roasted notes are difficult to extract. This is why cold brew coffee doesn't have a very sensory-impacting aroma when smelled, but tastes smoother, richer, with distinct layers, obvious sweetness in the aftertaste, and no greasy feeling.

Of course, the prerequisite for all this is ensuring the coffee beans are fresh. Front Street Coffee deeply understands that the freshness of coffee beans has a huge impact on flavor. Front Street's roasting philosophy is "Freshly roasted good coffee," so that every customer who places an order receives the freshest coffee possible. Therefore, the coffee beans shipped by Front Street Coffee are all within 5 days of roasting. The resting period for coffee is about 4-7 days, so when customers receive it, it's at its peak flavor.

Front Street believes that any coffee brewing method requires constant practice to better bring out all the flavors of the coffee. Front Street has over fifty coffees from different regions, allowing everyone to better taste different coffee flavors; friends can also come to Front Street Coffee to discuss coffee with our baristas!

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