Cold brew refers to a method of brewing coffee using cold or room-temperature water in place of hot water, with an extended steeping period ranging from several hours to over twenty-four hours.
Because heat is never applied, the extraction process is dramatically slower, producing a concentrate or a full-strength brew with distinctively low acidity, heavy body, and a smooth, rounded flavor profile.
Cold brew is not iced coffee. Iced coffee is brewed hot and then chilled, whereas cold brew is never heated at all.
Where it Actually Began: Japan, the Dutch, and Four Centuries of Uncertainty
The earliest documented evidence of cold-brew coffee comes from Japan, where records show the method was in use by the 1600s — well before the category had a name.
Japanese accounts from the Edo period describe a slow-drip technique in which cold water was allowed to pass through coffee grounds one drop at a time, a process taking many hours and producing a deeply concentrated, shelf-stable coffee liquid.
The most credible historical explanation for how this practice reached Japan points to Dutch trading vessels.
Dutch traders, who held significant commercial presence in Japan during the Edo period through the port of Dejima in Nagasaki — the sole point of permitted Western trade — are thought to have introduced cold-brewed coffee as a practical shipboard preparation.
Making coffee with fire on a wooden vessel was genuinely dangerous. Cold extraction required nothing but time.
Japan’s existing expertise in cold-brewing tea made the method culturally intuitive to adopt. What the Dutch brought as a practical solution, Japanese coffee culture absorbed and refined into something far more considered. The result became known as Kyoto-style coffee — named for the city where the slow-drip form of the method was most elaborately developed and most widely celebrated.
In 1840, French Foreign Legion troops stationed outside the fortress of Mazagran in Algeria mixed cold coffee concentrate with water and sugar to create a drink that was later adopted in Parisian cafés as the Mazagran — an early European ancestor of the iced coffee drink. This is a separate lineage from the Japanese cold-brew tradition and points to cold extraction appearing independently across different cultures in response to similar practical needs.
In 1963, an American chemical engineer named Todd Simpson travelled to Peru and encountered a local tradition of brewing coffee with cold water over an extended period.
Simpson returned to the United States and developed a commercial cold-brew system — the Toddy — which he patented and began selling. The Toddy became the dominant cold-brew system in American specialty and commercial coffee for decades, and the term ‘Toddy’ became, in many American coffee circles, a synonym for the cold-brew method itself.
Kyoto-Style Slow Drip: The Art Form Branch
Kyoto-style cold brew — also called Dutch coffee, ice drip coffee, and water drip coffee depending on geography — is the most technically elaborate expression of cold-brew methodology.
It uses a multi-chambered glass tower, sometimes reaching a meter or more in height, that holds cold water in an upper reservoir, channels it through a coffee grounds chamber at a precisely controlled drip rate, and collects the finished brew in a glass vessel at the base.
The drip rate is critical. Too fast, and the water rushes through the grounds without sufficient contact time, producing a thin, under-extracted liquid. Too slow, and the process becomes impractical. Experienced practitioners aim for one drop per second, though this varies by setup and desired strength. A full Kyoto tower brew can take anywhere from eight to twenty-four hours to complete.
The resulting coffee is extraordinarily clean. Because the water moves through the grounds continuously but slowly — never sitting long enough for over-extraction to occur — the brew captures the sugar-forward, floral, and fruity characteristics of the coffee without the bitterness and dark astringency that longer immersion cold brews can develop.
Kyoto-style coffee barely oxidizes during the extraction process, which contributes to its unusual flavor clarity.
The glass towers used for Kyoto-style brewing are objects in their own right. Tall, transparent, assembled from multiple glass components connected by adjustable valves and tubes, they became a feature of specialty cafés willing to invest in their visual impact as much as their functional output.
Seeing a Kyoto tower dripping in a café window is one of the more striking images in coffee culture.
Immersion Cold Brew: The Other Branch
Immersion cold brew — the method most people encounter today — is conceptually much simpler. Coarsely ground coffee is combined with cold or room-temperature water in a container and left to steep for twelve to twenty-four hours, then filtered through paper, cloth, or a fine metal mesh to remove the grounds.
What remains is a cold-brew concentrate or a ready-to-drink brew, depending on the coffee-to-water ratio used.
Ratios in cold-brew immersion typically run much higher than in hot brewing — somewhere between 1:4 and 1:8 coffee to water for concentrate, compared to 1:15 or 1:17 for a standard hot pour-over.
The intention is usually to produce a concentrate that can be diluted with water, milk, or ice at the time of serving. Cold-brew concentrate keeps well under refrigeration for up to two weeks without significant flavor degradation, a shelf life that has made it commercially attractive.
The Toddy system — a plastic vessel with a felt filter stopper in the base — became the standard commercial immersion cold-brew apparatus in the United States from the 1960s onward. Its simplicity and the shelf stability of its output made it widely adopted in cafés.
By the 2010s, mass-market cold-brew concentrates bottled under commercial brands had turned the method into a grocery category.
The Chemistry That Makes Cold Brew Different
Hot water extracts coffee compounds rapidly and in a specific sequence — acids first, then sugars, then bitter compounds. Cold water extracts the same compounds, but slowly and in a different ratio.
At low temperatures, the chemical reactions that produce acidity and bitterness are significantly suppressed, while sweet, chocolatey, and caramel-forward compounds remain proportionally more prominent in the final cup.
The result is a coffee that is measurably lower in acid than a comparable hot brew. Studies on cold-brew composition have consistently shown it to contain lower concentrations of chlorogenic acids and other organic acids than hot-extracted coffee from the same beans. This is not simply a matter of perception — the chemical profile is genuinely different, not just the temperature.
Caffeine content in cold brew is a common point of confusion. Cold brew concentrate contains more caffeine per unit volume than most hot brews because the coffee-to-water ratio is higher. But when diluted to drinking strength, the caffeine content is comparable to a standard cup of drip coffee.
Critics argue that ready-to-drink cold brew sold commercially at full concentration, without dilution, can contain significantly more caffeine than a typical cup — sometimes two to three times as much.
Nitro Cold Brew and the Modern Variations
In the 2010s, specialty cafés began infusing cold-brew concentrate with nitrogen gas using pressurized tap systems borrowed from the draught beer industry. Nitrogen, being a gas with very small bubble size, produces a cascading, creamy texture in cold brew — similar to a Guinness pint — without adding any sweetness or carbonation in the conventional sense.
Nitro cold brew became one of the fastest-growing coffee formats in the United States between 2015 and 2020, driven partly by Starbucks’ decision to introduce it system-wide and partly by its visual impact — the dark, cascading pour with a thick cream head is immediately striking.
The format spread to canned retail products, making nitrogen-infused cold brew shelf-stable and portable.
Japanese iced coffee — sometimes called flash-brew or hot-bloom iced coffee — is occasionally grouped with cold brew but operates on an entirely different principle. In this method, hot water is brewed directly onto ice, with the total liquid volume split between the hot water and the ice.
The heat extracts the bright acids and aromatics that cold water cannot, while the ice chills the brew instantly before oxidation can occur. The result is a different cup entirely — brighter, more acidic, and more aromatic— than cold brew’s smooth, low-acid profile.
Cold-brew coffee is also the base for several commercial products beyond ready-to-drink formats: cold-brew ice cream, cold-brew chocolate, and cold-brew spirits have all appeared in the market as the flavor profile found its way into adjacent food categories.
Who Uses It and Why the Category Grew
Cold brew’s commercial expansion in the 2010s was driven by several converging factors. It required minimal labor once the steep began, making it practical for cafés to prepare in large batches overnight.
Its shelf life meant it could be made ahead and served quickly, without equipment or technique at the point of sale. Its smooth, low-acid profile made it accessible to people who found hot coffee too harsh — a new entry point into the coffee category for a segment of consumers who had previously avoided it.
The growth of ready-to-drink cold brew as a retail category accelerated adoption further. By the mid-2010s, cold brew was no longer a specialty café phenomenon — it was a mainstream grocery item, a convenience store staple, and an ingredient in fast food menus.
The Kyoto-style slow-drip tradition that gave the method its oldest roots became, in the same period, a premium marker in high-end specialty cafés — the slow, elaborate, visual counterpoint to the mass-market version that had taken the same basic principle to industrial scale.