Given to the Water: A Slower Kind of Extraction

As the daylight slowly grows longer, the air by the window here in Minamiboso has taken on just a touch of moisture. Once the temperature starts to climb gently, I often get asked about cold brew coffee. Brewed slowly with cold water rather than hot, it is a way of drinking coffee worth easing into as the season ahead unfolds.

A customer who bought the Botarhythm Original Blend Touch the Earth shared this with me: "It's well balanced, and the presence of the bitterness is so pleasant that I end up drinking too much of it. Once it warms up, I'd like to try making a cold brew with it." Starting from a single cup, the imagination stretches toward the next way of enjoying it. As the person behind this shop, that was a note I was truly grateful to receive.

What Is Cold Brew Coffee

Cold brew coffee is a drink with an entirely different character from the ordinary method of brewing quickly with hot water. Cold water, slowly, over a long time. The time the beans spend steeped in water is itself what shapes the contours of the flavor.

Because no hot water is used, the extraction of the compounds behind bitterness and astringency stays gentle, and as a result, the mouthfeel settles into something round, with a clean, clear finish.

Beans Suited to Cold Brew

Beans with a darker roast and a well-balanced richness seem to suit the cold brew method well. Botarhythm's Original Blend Touch the Earth has a firm foundation of bitterness and body, and as it steeps in water over time, its edges gradually soften, letting the sweetness at its base come forward slowly.

The relationship between roast level and extraction is covered in more detail in another article, Coffee Roast Levels. Even with the same beans, the impression left by a hot brew and a cold brew will look different. I hope you'll try both approaches with a single bag of Touch the Earth.

How to Make Cold Brew Coffee

Grind Fine to Medium-Fine

What I recommend for cold brew is a grind in the fine to medium-fine range. Setting the grind a little finer lets the character of the beans carry fully into the water even when it's cold, giving the cup a well-defined core of flavor. How grind size affects extraction is something I touched on before in Coffee Tastes Better Fresh-Ground Than Fresh-Roasted, Part 2.

80g of Beans to 1000ml of Water Is My Guideline

What I often recommend is a ratio of 80g of beans to 1000ml of water. Setting the bean amount slightly higher than you would for a hot brew means the beans hold their own against the long extraction time, giving a cup with a solid, well-structured body.

One Bag, Ready to Go, for My Recommended Cold Brew

For anyone who finds adjusting the grind and measuring out coffee a bit of a hassle, I also offer the Botarhythm Cold Brew Coffee Pack, with beans already ground medium-fine and portioned into individual bags. The 1000ml version comes as 80g per bag times 5 bags, and the 500ml version as 40g per bag times 5 bags, a configuration that reproduces my recommended ratio (80g of beans to 1000ml of water) exactly. The beans are ground only after your order comes in, so you can enjoy the aroma of freshly ground coffee right when you open the bag.

Steep at Room Temperature for 12 to 24 Hours, Then Refrigerate

Combine the ground beans and water in a sealable glass container. I carry the HARIO KA-KU Cold Brew Coffee Bottle, a square bottle that comes with a built-in strainer, where the ground beans go directly into the strainer for brewing. Once the beans and water are combined, leave the container at room temperature for about 12 to 24 hours first. The flavor moves slowly into the water during that time at room temperature, and once the extraction has settled, move it to the refrigerator to chill. This two-step process is what I recommend. Passing the finished liquid through a strainer once more into a glass container brings the clarity of the finish into even sharper focus.

Extraction Is a Time for Waiting

The word "extraction" carries a sense of "drawing something out," but the time spent on cold brew feels closer to "waiting." The flavor moves gradually from the beans toward the water. There is almost nothing to actively do during that shift. Choose the beans carefully, set the grind, measure the water, and once those three things are in order, all that's left is to leave it to time.

Frequently Asked Questions

What beans work well for cold brew coffee?

Beans with a darker roast and a well-balanced richness suit it well. I recommend Botarhythm's Original Blend Touch the Earth.

How long should cold brew steep?

I recommend leaving it at room temperature for about 12 to 24 hours before moving it to the refrigerator. The time at room temperature is what creates that slow transfer of flavor.

What's the ratio of beans to water?

My guideline is 80g of beans to 1000ml of water. Feel free to adjust the amount of beans to taste, depending on how strong or light you'd like it.

What grind size should I use?

I recommend a range from fine to medium-fine. Setting the grind a little finer makes it easier for the flavor to carry through, even in cold water.

How is cold brew different from ordinary hot brewing?

Because no hot water is used, the extraction of the compounds behind bitterness and astringency stays gentle. As a result, the mouthfeel comes out round, with a clean, clear finish.

What equipment would you recommend for cold brew?

Any sealable glass container will do, but I carry the HARIO KA-KU Cold Brew Coffee Bottle. If adjusting the grind feels like too much trouble, the Botarhythm Cold Brew Coffee Pack, portioned into individual bags at my recommended ratio, is also worth a try.

Today too, at the Botarhythm Coffee Roaster roastery, the roaster Nobuaki Motozawa is quietly roasting beans. In this season when temperature and humidity shift so gradually, the time spent on extraction itself can feel a little more deliberate than usual. I hope you enjoy the conversation between water, time, and the beans.