ou want iced coffee that is bright and clean. Cold brew takes twelve hours. This takes three minutes.
Flash brew brews hot coffee directly onto ice in the server. The brew chills on contact, so the flavors lock in before oxidation softens them. The result is closer to a chilled pour-over than to anything you have had from a carafe in a diner.
The method comes from James Hoffmann, who popularized the technique with a simple ratio: brew onto a bed of ice, let the ice melt into the cup, drink it immediately. The recipe below follows his approach.
At a glance
The total yield depends on how fully the ice melts. At full melt with no bed retention you get roughly 330 g of iced coffee, approximately a 1:15 ratio total. In practice the brew bed holds back some liquid, so your cup is usually closer to 280 to 300 g. Either is normal.
The hot-water and ice split
The split matters because the ice dilutes the brew as it melts. You brew at a concentrated ratio (200 g water for 22 g coffee, roughly 1:9 hot-only) so that the meltwater brings the final cup into balance. Brew with too much water and the cup will be thin. Use too little ice and the coffee stays hot and flat.
The 60:40 split (approximately 200 g hot water and 130 g ice) is the figure James Hoffmann uses. Counter Culture, whose recipe is also well-regarded, runs hotter: roughly 365 g hot water over 135 g ice for a larger batch, which computes to about 73:27 hot to ice. Both work. The difference is mostly grind compensation. A hotter split means less dilution, so you grind slightly finer to concentrate the brew.
The steps
Set your server on the scale and add 130 g of ice. Tare the scale. Rinse the paper filter with hot water, discard the rinse water (into a separate cup, not over the ice), and add 22 g of ground coffee. Level the bed gently. Start the timer with the first drop of water.
- BloomPour 44 g of water (twice the dose) slowly and evenly over all the grounds. Wait for the bed to settle and the initial gassing-off to slow. About 40 seconds total.00:4044 g93 °C
- First pour to 120 gPour in slow concentric circles from the center out, bringing the total hot water to 120 g. Aim to finish this pour around 1:25 from the start.00:45120 g93 °C
- Second pour to 200 gContinue in the same slow circles up to 200 g total hot water. Aim to have all the water in by about 2:25.01:00200 g93 °C
- DrawdownLet gravity finish. The bed should drain in about 35 seconds, bringing the total to near 3:00. Do not stir. The ice is doing its work below.200 g
The step durations above are approximate interpolations from the documented pour targets. James Hoffmann publishes the ratio and the overall structure; the per-step times here are working estimates that land the brew in the documented three-minute window.
Why brew hot onto ice
Hot water extracts coffee more efficiently and selectively than cold water. Cold brew takes twelve or more hours because low temperature slows extraction. Flash brew gets the extraction benefits of hot brewing, then locks the flavors in by chilling instantly on the ice.
The rapid chill also limits the oxidation that flattens a hot coffee left to cool slowly. Pour a hot V60 into a glass and let it cool for twenty minutes and the acidity goes dull. Pour the same brew onto ice and it stays vivid. That is the whole argument for flash brew.
The grind needs to be slightly finer than your usual V60 grind because the concentrated ratio (roughly 1:9 hot-only) asks more from the bed. Start at your normal V60 setting and step it one notch finer. If the drawdown stalls well before three minutes, open it up slightly.
Reading the cup
Taste the cup once the ice has melted and the temperature is around five degrees. That is the intended drinking temperature, and the flavor reads differently from hot.
If the cup is thin and sour, you are under-extracting. Grind one step finer. If the cup is bitter or harsh, grind coarser or drop the temperature to around 91 °C. If it tastes watery rather than thin, your ice was too heavy or melted before brewing started; reduce the ice charge by 10 g next time.
Flash brew rewards lighter roasts and coffees with higher acidity. A bright washed Ethiopian or a clean Colombian will give you something genuinely different from a hot brew of the same bean. A heavy dark roast is less interesting here.
Common questions
- Why not just brew a normal V60 and pour it over ice?
- You can, but the result is different. Brewing over ice (flash brew) chills the coffee rapidly on contact. Brewing normally and then pouring over ice lets the coffee oxidize and cool slowly first, which softens the acidity and can add a flat note. Flash brew catches the flavor before that happens.
- What ice is best?
- Dense, slow-melting cubes from a tray or a purchased bag. The goal is ice that chills the brew rather than melting away instantly. Crushed ice melts fast and can over-dilute before all the coffee has dripped through.
- The recipe says roughly 60:40 hot to ice, but I have seen other recipes that use much less ice. Which is right?
- Both can work. The split you choose affects how concentrated you need to brew. James Hoffmann uses approximately 60:40 (about 200 g water and 130 g ice for a 22 g dose). Counter Culture runs a hotter split, around 73:27. A hotter split means less dilution, so you grind slightly finer to compensate. Start at 60:40 and adjust from there.
- Can I use a different dripper?
- Yes. The method works with any pour-over dripper that fits over your server. A Kalita Wave or a flat-bed dripper both work. The recipe numbers were developed for a V60, so drawdown time may differ slightly with another dripper.