The 4-Hour Cold Brew: A Faster Way to Make Sweet, Flavorful Coffee

Craving a glass of smooth, refreshing cold brew but daunted by the typical 8 to 12-hour wait? I understand completely. The long steeping time, necessary for both slow extraction and flavor development through fermentation, means you usually have to plan a day ahead.

But what if you get a sudden craving and want to enjoy a cold brew today?

Fortunately, there's a way. Since the slow extraction rate of cold water is the main time constraint, we can speed things up by slightly increasing the water temperature. This significantly cuts down the required brewing time, allowing you to make and enjoy cold brew on the same day.

The Science of a Quick Cold Brew

Now, you might be thinking, "Isn't that just hot coffee? The whole point of cold brew is the 'cold' part!" And you're right. The magic of cold brew lies in its low-temperature extraction, which brings out more delicate floral and fruity notes compared to high-temperature methods.

The secret is the slow release of flavor compounds from the coffee grounds. Acidity and sweetness are the first to be extracted in large amounts. Bitterness follows much later. Traditional cold brew’s long, slow process extracts the delightful acids and sugars while stopping short of releasing a significant amount of bitter compounds. This results in a naturally sweet, aromatic coffee with low bitterness.

This is precisely why we can't just use hot water—it would extract everything, including the bitterness, within minutes. The solution is to use warm water, not hot. Based on an experiment I conducted six months ago, I found that 40°C (104°F) is the perfect temperature to accelerate extraction without introducing unwanted bitterness.

The Experiment: Finding the Best Quick Method

A reader recently asked a great question: would blooming the coffee with 92°C (198°F) water before adding cold water yield better results than using 40°C water for the entire process?

To find out, I set up a side-by-side comparison of three methods. For the control, I made a traditional cold brew the night before. All three brews used the same exceptional coffee: a Colombia Finca Villa Betulia - Pink Bourbon. This coffee is perfect for the experiment with its bright fruit acidity, rich floral aroma, and a unique pink peppercorn note.

Here are the parameters for each brew:

Brew Methods

• Method 1: Traditional Cold Brew (Control)

  • Coffee: 20g (EK43 Grind: 10)

  • Water: 240ml at 23°C (73°F)

  • Ratio: 1:12

  • Time: 10 hours, refrigerated

• Method 2: 40°C Warm Water Cold Brew

  • Coffee: 20g (EK43 Grind: 10)

  • Water: 240ml at 40°C (104°F)

  • Ratio: 1:12

  • Time: 4 hours, refrigerated

• Method 3: Hot Bloom Cold Brew

  • Coffee: 20g (EK43 Grind: 10)

  • Water: 40ml at 92°C (198°F) to bloom, then 200ml at 23°C (73°F)

  • Ratio: 1:12

  • Time: 4 hours, refrigerated

The Process

For the warm water brew, I combined 20g of coffee with 240ml of 40°C water and stirred. For the hot bloom version, I stirred 20g of coffee with 40ml of 92°C water, then added 200ml of room-temperature water.

Both were sealed and placed in the refrigerator for 4 hours. Afterwards, I filtered each one and did a taste test.

Tasting Results

• Traditional Cold Brew: The winner in complexity. It had a full, rounded body with notes of berry and a distinct pink peppercorn flavor. The fermentation notes were prominent, making it taste like a spiced strawberry juice.

• 40°C Warm Water Cold Brew: The best fast alternative. This version also had an excellent berry flavor and pronounced sweetness. While slightly less rounded than the traditional brew and with weaker fermentation notes due to the shorter time, the signature pink peppercorn flavor was still present and enjoyable.

• Hot Bloom Cold Brew: This tasted more like a balanced iced pour-over coffee, with acidity, sweetness, and bitterness all present. It had the weakest fermentation character of the three.

Conclusion

If you need great cold brew in a hurry, the 40°C warm water method is the clear winner. It produces a "quick cold brew" that is remarkably close to the traditional version. While it may not have the full depth and complexity of a 10-hour steep, it delivers a flavorful, sweet, and aromatic cup with pleasant fermentation notes in just 4 hours—perfect for satisfying that immediate coffee craving.