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Cold Brew Coffee Ratio: 8 Tips for Making the Best Cold Brew Coffee

Published: 2026-01-27 Author: FrontStreet Coffee

Last Updated: 2026/01/27, Choose your coffee wisely, whether you buy whole beans or pre-ground coffee makes no difference. What matters most is selecting quality coffee, so you can make the most of it through cold brew. This doesn't mean you should buy the most expensive coffee; instead, you should try different coffees until

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The original intention of cold brew coffee is that under low-temperature conditions, small molecules that tend to be aromatic and acidic are more easily released in cold water. Therefore, the coffee tastes light and predominantly presents sweet and sour notes. Additionally, because it's not limited by equipment or venue, cold brew can be considered easily accessible coffee. At home, as long as you have ingredients, a bottle, water, and a refrigerator, you can easily achieve caffeine freedom.

At this point, some observant coffee enthusiasts have noticed a phenomenon: Unlike pour-over coffee, which almost always maintains an unchanging 1:15 ratio, the coffee-to-water ratio for cold brew varies greatly. Some prefer using 1:8, others advocate for 1:13, and there are those like FrontStreet Coffee who are accustomed to using 1:10 for their products. So what kind of taste experience do cold brews made with different ratios offer?

What Effects Do Coffee-to-Water Ratios Have on Coffee?

As a typical immersion extraction method, cold brew coffee involves low-temperature water and coffee grounds remaining in the same container for extended periods, thereby extracting flavors. When other parameters remain constant, the higher the water proportion, the lower the concentration of the coffee liquid, resulting in a lighter coffee taste and thinner mouthfeel; conversely, the less water proportion, the higher the concentration, resulting in a stronger taste and thicker mouthfeel.

Therefore, to find a balanced mouthfeel and allow the coffee to present its optimal flavors, we need to apply an appropriate coffee-to-water ratio.

How Long Should Cold Brew Steep? How Fine Should Coffee Grounds Be?

We all know that the various parameters involved in any extraction method are interrelated to some extent. For cold brew, the coffee-to-water ratio is not the only factor that determines taste; we must also consider grind size, steeping time, water quality, and most importantly, the coffee beans themselves.

Although low-temperature extraction can reduce the appearance of bitter substances, it's not 100% effective. Therefore, to pursue delicious flavor, coffee grounds used for cold brew should not be ground too finely, nor should they steep for too long. For the former, we recommend controlling it to about 80-85% pass-through rate on a 0.85mm standard sieve, which visually appears similar to granulated sugar particles; the latter should ideally be controlled within 6-16 hours, as this ensures sufficient contact time between coffee grounds and water while avoiding negative flavors from over-extraction.

FrontStreet Coffee emphasizes water quality not only because it's the extraction medium but also because it's the most easily overlooked parameter among all. For example, FrontStreet Coffee frequently receives inquiries from customers who have purchased our coffee beans and followed the parameters provided in our articles to make cold brew, yet the taste doesn't meet expectations. After eliminating various "culprits," they discover that the problem actually comes from that colorless and tasteless "water." Friends with similar troubles can refer to FrontStreet Coffee's past comparative experiment "Making Cold Brew with Different Water - The Difference is Surprisingly Huge!" We won't elaborate further here.

In terms of coffee bean selection, FrontStreet Coffee uses Kenya·Little Tomato from our bean shelf as an experimental demonstration. It uses the K72 washed processing method, with SL28 and SL34 varieties. Both SL28 and SL34 are varieties selected after multiple breeding rounds. SL28 belongs to the Bourbon genetic group, carrying the bright tone and rich acidity of original Bourbon; SL34's lineage is closer to Typica genes, with milder acidity.

Kenya AA, when made into iced coffee, presents a sensation of dark berries enveloping the palate, accompanied by rich little tomato aroma. When consumed chilled, it's extremely refreshing, making it a preferred bean choice for many friends when making cold brew.

How Do Cold Brews Made with Different Coffee-to-Water Ratios Taste?

Since cold brew always occurs in a 0-10°C environment, extraction efficiency is very low. Additionally, coffee grounds and water are in a relatively static state, and there's no external force applied during the process, so the speed at which coffee grounds dissolve flavor compounds is quite limited. To make the experimental results clearer, FrontStreet Coffee has set up four common coffee-to-water ratios: 1:8, 1:10, 1:12, and 1:15, while keeping all other parameters unchanged.

The production process is completely identical: coffee grounds and water are poured into the container in sequence, then stirred, sealed, and placed in the refrigerator. When the time is up, we take it out and filter it (stirring once midway is acceptable).

Coffee Beans: Kenya·Little Tomato
Coffee Amount: 18g
Steeping Time: 6 hours
Grind Size: Granulated sugar/China No. 20 standard sieve pass-through rate 80% (EK43s setting 9.5)
Coffee-to-Water Ratio: 1:8, 1:10, 1:12, 1:15
Corresponding Water Amount: 144g, 180g, 216g, 270g

The 1:8 coffee liquid has the darkest color, strongest taste and acidity, with a slightly salty mouthfeel, minimal berry flavors, and a bitter aftertaste.

The 1:10 coffee liquid smells of fresh sugarcane, with flavors of red plum, berries, and pear tea. The mouthfeel is slightly concentrated, with high acidity and不明显sweetness.

The 1:12 cold brew has the clearest mouthfeel, with flavors of little tomato, red plum, dark plum juice, sugarcane, and the aftertaste of preserved plum candy. The concentration is moderate, with a balanced sweet and sour profile.

The 1:15 coffee liquid has the lightest color, thinner body, with only slight acidity from black plum and berries. The taste is plain, but there's almost no bitterness.

From the above comparison, it's not difficult to see that the 1:8 ratio, due to less water usage, doesn't provide enough space for coffee flavors to develop and easily exhibits negative characteristics of being thick and bitter; conversely, the 1:15 ratio, due to more water usage, has soluble substances overly diluted, resulting in insufficient coffee richness, naturally making it taste bland and flavorless.

Between the 1:10 and 1:12 groups, the cold brew made with 1:12 clearly performs best in terms of flavor and mouthfeel when consumed directly. However, FrontStreet Coffee prioritizes using 1:10 in many articles and daily products. Why is this?

For cold brew products, FrontStreet Coffee mainly considers two factors.

First, to maintain the cold temperature of the cold brew, we not only use chilled glasses but also add 1-2 hard ice cubes. This way, even if the coffee is diluted, the flavor won't change too much.

Second, because each customer has different taste preferences—some like light, some like strong—when ice cubes are first added, the coffee taste is full and thick. As they slowly melt into water over time, the coffee gradually becomes lighter. Therefore, using high-concentration cold brew with ice satisfies both the "strong flavor camp" and the "light flavor camp."