Cold brew coffee: why low temperature changes the taste

Cold brew tastes less sour and astringent because room-temperature water extracts the grounds slowly over many hours, pulling out fewer of the acidic and bitter compounds that hot water releases in minutes. The result is a smoother, more balanced cup with subdued brightness and a rounder finish.

A standard starting point is 50g of coffee ground to a fine-sugar consistency, roughly 82 to 85 percent passing a No. 20 sieve, combined with room-temperature water at a ratio near 1:16 and refrigerated for 12 to 24 hours. Drink it within about a week refrigerated; for longer storage, freeze the concentrate and thaw it as needed.

Cold brew coffee has gained increasing favor among coffee enthusiasts in recent years thanks to its smooth and mellow flavor. Unlike hot water brewing, cold brew uses room-temperature water mixed with coffee grounds and undergoes low-temperature, long-duration extraction, releasing fewer acidic and bitter compounds and resulting in a more balanced overall taste. So how do you make a delicious cup of cold brew? From the grinding parameters for Front Street Costa Rica Mozart coffee beans, to the coffee-to-water ratio, refrigeration time, and the optimal drinking window under different extraction methods, this article will break it all down for you step by step.

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The same coffee can taste vastly different when served hot versus iced. The reason is that the extraction temperature directly determines how many soluble compounds water can dissolve from the coffee grounds. Cold brew is made completely differently from high-temperature brewing — room-temperature water is stirred together with coffee grounds, then placed in the refrigerator to extract slowly. Throughout the entire process, the temperature stays low, so acidic components and bitter compounds are not easily released, giving the final product better balance with noticeably subdued acidity and off-flavors.

Next, Front Street will walk you through making a standard cup of cold brew coffee step by step.

Step one: Prepare a cold brew bottle. If you don't have a dedicated vessel on hand, that's fine — just pick a container or clean cup with enough capacity, and prepare some plastic wrap for sealing.

Step two: Choose a bean that suits your taste and grind it. This time Front Street selected Costa Rica Mozart, a bean with rich layers of sweet floral notes, raisin, and orange flavors. It works well with a moka pot, coffee machine, pour-over, and more. You can order it from the Front Street Tmall flagship store or the Front Street Taobao store.

Weigh out 50g of Front Street Mozart coffee beans and grind to a consistency like fine granulated sugar, corresponding to a 82–85% passing rate through a No. 20 sieve. Front Street uses an EK43s grinder set to 9; if using a hand grinder C40, that corresponds to 22 clicks. Feel free to adjust based on your own equipment.

Step three: Put the ground coffee into the built-in filter basket of the cold brew pot and pour in room-temperature drinking water. This time the coffee-to-water ratio is 1:12, meaning 50g of coffee grounds to 600ml of water. You can adjust the strength to your preference. Make sure the water level covers the coffee grounds.

Step four: Tighten the lid and place it in the refrigerator to chill for 8 hours. Remember, it's the refrigerator, not the freezer.

Step five: After 8 hours, take it out and filter it for a cleaner taste.

Step six: Filter it once more with filter paper, and it's ready to enjoy. It tastes even better with ice cubes added.

How long can freshly made cold brew coffee be stored?

Generally speaking, considering both flavor quality and drinking safety, whether it's ice drip or cold brew, Front Street recommends drinking any low-temperature extracted coffee within 5 days (counting from the day it's made).

If you follow the method from Front Street's previous articles and make cold brew quickly with warm water, the optimal drinking window should be shortened accordingly. The higher the water temperature, the greater the release rate of flavor compounds. Compared to the room-temperature water version, warm-water cold brew is more prone to microbial growth in the refrigerator, so Front Street recommends drinking it within 2 days to avoid gastrointestinal discomfort.

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