One cup now, without an overnight steep
Flash brewing extracts with hot water directly onto a measured amount of ice. Cold brew steeps grounds in cold water for hours; the two methods are different even when served in similar glasses.
Use a cone dripper and matching paper, a heat-resistant server suitable for hot and cold liquids, scale, kettle and clean potable-water ice. This is an editorial starting recipe. Estimated drink after the planned ice melts is about 280 ml, allowing roughly 40 g water to remain with the 20 g coffee.
The iced-coffee calculator scales the hot-water and ice amounts; use this guide for the actual pouring and serving sequence.
Flash brewing keeps the paper-filtered texture of its hot extraction. Cold brew can also be paper-filtered, but a mesh-only batch leaves a different amount of suspended material. The brew temperature and filtration are separate choices; neither label alone guarantees a flavor, caffeine level or acidity.
| Ingredient or setting | Starting point |
|---|---|
| Coffee | 20 g, medium-fine, slightly finer than your hot recipe if needed |
| Hot water | 200 g at 96°C / 205°F |
| Brew ice | 120 g in the server |
| Total recipe water | 320 g including counted ice |
| Pours | 60 g bloom; 130 g cumulative; 200 g cumulative |
| Timing | Bloom 45 seconds; second pour from 0:45; final from 1:15; observe finish around 2:15–3:00 |
Evidence: Whole Latte Love: Japanese iced-coffee brewing example
Count ice before you pour
Only the hot-water targets appear on the tared scale during brewing. Do not pour 320 g hot water on top of the recipe's 120 g ice.
- Rinse and warm the filter using a separate vessel, then discard that rinse water. Weigh 120 g ice into the brewing server.
- Put the dripper on the server, add 20 g coffee, level it and tare the assembled setup.
- Start the timer and wet the grounds with 60 g hot water. Wait until 0:45.
- Pour gently to 130 g cumulative, then begin the final pour around 1:15 and stop at 200 g.
- Let the bed drain, remove the dripper and swirl the server to mix and melt the planned ice. Some remaining ice is possible, depending on temperatures and heat loss.
- Taste. Pour over extra serving ice if desired, recording that this will add more dilution as it melts.
Keep hot water and ice in proportion
The starting split is 62.5% hot water and 37.5% ice. Scaling keeps the same arithmetic but not necessarily the same drawdown time; larger batches need a suitable dripper and server.
For that two-drink version, use 40 g coffee, 240 g counted ice and hot-water targets of 120 g bloom, 260 g cumulative and 400 g final. Those are additions of 120, 140 and 140 g. Use a suitable larger dripper and a heat-safe server with safe working room for the full 640 g water-equivalent batch, solid ice and headspace; a 500 ml server is too small. If the brewer cannot hold the deeper bed and slurry safely, make two 20 g batches instead. Observe the larger brew rather than forcing its finish time to match one cup.
| Total recipe water | Coffee at 1:16 | Hot water | Brew ice | Estimated finished drink |
|---|---|---|---|---|
| 240 g | 15 g | 150 g | 90 g | 210 ml |
| 320 g | 20 g | 200 g | 120 g | 280 ml |
| 500 g | 31.25 g | 312.5 g | 187.5 g | 437.5 ml |
| 640 g — twice the starting recipe | 40 g | 400 g | 240 g | About 560 ml, two approximately 280 ml drinks |
Taste after mixing, before changing everything
Less hot water travels through the grounds than in the corresponding hot recipe. A small finer adjustment or hotter brewing water can help extraction, but neither should cause overflow.
| Problem | First test |
|---|---|
| Sour and thin | Try a little finer with the same hot-water/ice split; ensure the bloom wets all the coffee. |
| Balanced but watery | Check uncounted serving ice or milk before increasing the dose. |
| Coffee is still warm | Check that the planned ice was weighed and actually present; chill the serving glass and use fresh serving ice as needed. |
| Too strong with intact ice | Swirl and allow the counted ice to melt before judging final strength. |
| Bitter or drying | Reduce agitation or use a slightly lower temperature, one change at a time. |
| Drawdown stalls | Stop pouring if overflow threatens; next brew reduce fines/agitation and check paper fit. |
No dripper: choose a method with a clear water plan
No dripper is required for the other immediate routes: use the upright iced AeroPress recipe, or dissolve instant in a measured hot-water portion before adding cold water and ice. Each route states its own coffee, water and ice instead of borrowing the flash-brew ratio.
For iced espresso and milk, or moka coffee over ice, brew the base normally and treat milk, water and ice as serving additions. Espresso yield remains the extracted drink; added milk does not change the shot's dose-to-yield ratio.
A cooled-batch option uses an ordinary hot brew made from its full recipe. Transfer the coffee into clean suitable smaller containers and refrigerate promptly at 4°C / 40°F or below; keep covered and date it. For a measured serving, 150 ml chilled black coffee plus 50 g ice approaches 200 ml as that ice melts, so it will become weaker. A chilled cup without added ice preserves the starting concentration. This method needs cooling time and gives a different handling routine from brewing directly onto recipe ice.
Add refrigerated milk at serving time and follow its package guidance. Do not leave milk coffee on the counter waiting to become cold brew. The cold-brew storage discussion explains the source-backed refrigeration and handling limits; this alternative does not establish a universal home shelf life.
Evidence: FDA: food storage and temperature
Serve, then clear the wet filter
Discard the cooled paper and grounds, wash the dripper and server and clean any coffee trapped under melting ice in the serving glass. Make ice from potable water in clean trays. Handle the hot brewer carefully even though the drink beneath it is cold.
Sources & limitations
This guide combines source-based explanations and practical starting points. Coffee Jacob has not performed hands-on product testing or controlled tasting trials for this guide. Source check: 13 October 2026.