Is Cold Brew Made with Warm Water Any Good?

 Most people think cold brew coffee must be made slowly with cold water — but what if a little warmth could unlock new layers of flavor? In this post, we explore the science and art of brewing cold brew with warm water. You’ll learn how temperature changes affect extraction, what flavors to expect, and how to try this quick yet refined method at home. Think of it as the middle ground between the patience of cold brew and the intensity of hot brewing — a balanced cup born from gentle warmth and slow craftsmanship.

Is Cold Brew Made with Warm Water Any Good?

As one of the most popular types of iced coffee, cold brew is typically made using room-temperature water (around 20–30°C / 68–86°F). Because the extraction efficiency is relatively low, the coffee needs to steep for a long time to fully draw out its flavors, emphasizing sweetness and body.

Anyone who’s made cold brew before knows the process takes time — anywhere from 5–6 hours to nearly an entire day. Compared to other brewing methods, cold brew is clearly a “slow craft.” Because of that, some people have suggested using warm water instead to shorten the steeping time.

Out of curiosity, I looked into it and found that brewing cold brew with warm water isn’t exactly new. Many coffee enthusiasts have tried it before and even reported that it enhances sweetness. So today, let’s explore whether that really works.

Cold Water vs. Warm Water Brewing

In essence, compared with high-temperature extraction, the long, cool immersion of cold brew allows more of the coffee’s smaller sweet and acidic compounds to dissolve, while the low temperature suppresses the release of bitter compounds — especially when brewed and stored in the fridge. This results in a smoother, cleaner cup.

A study jointly published by the Coffee Science Foundation and the Specialty Coffee Association found that coffee extracted at lower temperatures tends to have more floral and fruity notes, with less bitterness, acidity, and off-flavors.

For the same coffee bean — using identical ratios, grind size, and coffee weight — the rate at which compounds dissolve in hot vs. cold water varies significantly. According to the data, flavor characteristics change noticeably with extraction temperature. Among four key attributes — bitterness, acidity, rubbery flavor, and floral aroma — the first three are higher in hot extractions, while floral notes are more pronounced in cold brews.

During high-temperature brewing, tannins break down into gallic acid, and more fatty acids dissolve, leading to stronger bitterness and acidity. In contrast, under low-temperature extraction, as steeping time increases, acidic compounds gradually decrease. That’s why cold brew has much lower acidity and bitterness. The chilled environment also helps trap more aromatic compounds, “locking in” the coffee’s fragrance.

When using warm water (somewhere between cold and hot), the added heat boosts molecular movement and allows small flavor compounds to release more quickly. As the water cools, the temperature drop prevents coffee particles from clumping and promotes even extraction, while still limiting bitterness.


How to Brew Warm-Water Cold Brew

For this experiment, I used Elida Catuai, a Panamanian coffee processed with anaerobic natural fermentation. It features soft floral aromas with notes of sweet orange and plum jam — a bright and delicate profile perfect for both pour-over and cold brew.

Since higher temperatures increase the risk of over-extraction from fine particles, I adjusted the grind slightly coarser for better balance.

Brew parameters:

  • Coffee: 30g

  • Grind: EK43s – 10 clicks (75% passing through a 20-mesh sieve, or Comandante C40 – 26 clicks)

  • Coffee-to-water ratio: 1:11

  • Water temperature: 45°C (113°F)

Steps:

  1. Add the ground Elida coffee to a clean container.

  2. Pour in 330ml of water at 45°C and stir thoroughly.

  3. Once the coffee cools to around 35–40°C, seal it and place it in the fridge.

  4. After about 3 hours, stir again and filter out the grounds.

For comparison, I also made a standard cold brew using room-temperature water with these parameters:

  • 30g coffee, grind size EK43s – 10 clicks, 1:11 ratio, steeped for 7 hours.

The room-temperature cold brew had delicate floral, pineapple, and orange notes, with a light black-tea sweetness and slight fermentation — nicely balanced overall.

The warm-water brew (40°C for 3 hours), on the other hand, had elegant bergamot and jam aromas with brown sugar and peach sweetness. However, the flavors felt a bit underdeveloped with a short finish — likely due to incomplete extraction.

So, I sealed it again and refrigerated it for another 3 hours. As expected, the cup became much fuller and rounder, with a richer aroma and smoother taste.

A Few Takeaways

  1. I also tested a few other beans and found that light to medium roasts with fruity or sweet profiles work best with this warm-water cold brew method — for example, natural-processed ALO or honey-processed Strawberry Candy.

  2. If you don’t have a thermometer, don’t worry — “warm water” simply means water close to body temperature. As long as it feels gently warm to your hands, it’s perfect.

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