Tetsu Kasuya's Iced Coffee Recipe: Hot-Bloom-Then-Ice Method Translated
Updated May 2026Editorial disclaimer: This guide is independent editorial commentary. We translate, interpret, and stress-test recipes from Japanese coffee culture for English-speaking brewers. Quoted material is paraphrased or excerpted under fair use for criticism and education. We are not affiliated with Tetsu Kasuya, Philocoffea, Hario, or any roaster mentioned. Affiliate links may earn us a small commission at no cost to you.
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Last updated: May 2026
Editorial disclaimer: This guide is independent editorial commentary. We translate, interpret, and stress-test recipes from Japanese coffee culture for English-speaking brewers. Quoted material is paraphrased or excerpted under fair use for criticism and education. We are not affiliated with Tetsu Kasuya, Philocoffea, Hario, or any roaster mentioned. Affiliate links may earn us a small commission at no cost to you.
Tetsu Kasuya's Iced Coffee Recipe: Hot-Bloom-Then-Ice Method Translated
If you've spent any time in Japanese specialty coffee circles, you've heard the argument. Cold brew is smooth but flat. Flash-chilled pour-over is bright but thin. Neither one captures what Tetsu Kasuya — the 2016 World Brewers Cup champion and founder of Philocoffea in Funabashi — actually serves over ice.
His answer is a third path. Hot bloom, then ice. A short, controlled hot phase that wakes the coffee up, followed by ice-water dilution that pulls extraction down to a lower temperature without ever letting the cup go bitter.
It is not flash brew. It is not mizudashi. It is its own thing, and once you brew it correctly, it's hard to drink anything else in summer.
This guide translates Kasuya's method from Japanese-language sources, his Philocoffea blog, and his English-subtitled YouTube content into a recipe an English-speaking brewer can run on a Tuesday morning. We compare it to four other iced methods, list the eight stats you actually need, and answer the questions most people get wrong on their first try.
Quick Answer
- The recipe: 20g coffee, 100g hot water (92 degrees C), 100g ice, total beverage yield ~150g. Bloom hot, finish cold. About 3 minutes 30 seconds total.
- The ratio: 1:10 total water-to-coffee, with 50% of that "water" delivered as ice sitting in the server. At Philocoffea's shop scale, the ratio shifts to 1:6:6 (coffee:water:ice) for higher concentration. Home brewers can pick either.
- Why hot bloom: Hot water at bloom temperature extracts the volatile aromatic compounds — the things that make Ethiopian coffee smell like blueberry — that cold water leaves locked in the bean.
- Why ice in the server: It flash-chills the brew, locks in those aromatics, and dilutes the extraction to drinking strength in one move. No watering down a strong brew after the fact.
What enthusiasts report on Reddit (2024-2026)
"I love Tetsu Kasuya's new hybrid switch recipe with light roasted SEY beans. Had a Gesha I was brewing a few weeks back and loved it. Less clarity in the brew but the sweetness and jamminess was overwhelming and amazing. If I brewerd the same bean v60, I could get more clarity but it would be a bit more tea like" — u/yaoman11 on r/pourover, 2025-02
"Tetsu Kasuya's Devil's switch recipe. Bloom and first pour at 90, followed by an immersion phase at 70. Light on the palette and extremely low bitterness. Harder to extract coffees can require hotter water for the bloom and first pour" — u/ruckssed on r/pourover, 2024-12
"As many pointed out, the grind looks too fine for pour-over. You could also time the extraction. Usually for V60 it should be in the range of 2-3min (both James Hoffmann's recipe for one-cup V60 and Tetsu Kasuya's 4:6 method). If it takes longer, you are most likely over extracting and if it's shorter, then under extraction is likely possible." — u/coolmandarin on r/pourover, 2025-03
The Recipe, Translated
Here is the home version of Kasuya's iced coffee, scaled for a single Hario V60 02 dripper. This is the recipe he demonstrates on his Japanese YouTube channel and that Philocoffea's English shop notes describe in their iced brewing post.
Equipment
- Hario V60 02 ceramic or plastic dripper
- V60 02 paper filter (white, bleached)
- Server or carafe that holds at least 400ml
- Gooseneck kettle (Fellow Stagg, Hario Buono, or equivalent)
- Burr grinder (Comandante, 1Zpresso, Timemore Chestnut)
- Scale with 0.1g resolution and timer
- Ice — clean cubes, ideally filtered water frozen the night before
Recipe Card
| Variable | Value |
|---|---|
| Coffee dose | 20g |
| Grind size | Medium-fine (slightly finer than your hot V60 setting) |
| Hot water | 100g |
| Ice | 100g (placed in the server, not the dripper) |
| Water temperature | 92 degrees C / 198 degrees F |
| Total brew time | ~3:30 |
| Final beverage yield | ~150g (after melt) |
| Ratio (effective) | 1:10 water-to-coffee |
Step by Step
- Place 100g of ice in your server. Not in the dripper. The ice sits below, waiting for hot coffee to fall onto it.
- Rinse the paper filter with hot water. Discard the rinse water from the server before adding ice. (Yes, this means rinsing first, drying server, then loading ice.)
- Grind 20g of coffee at medium-fine. Slightly tighter than you'd grind for a hot V60. The shorter contact time of this method needs help on extraction.
- Add coffee to dripper, level the bed with a tap.
- Start timer. Pour 40g of hot water (92 degrees C) in a tight circle over the grounds. This is your bloom. Let it sit 45 seconds. You should see vigorous CO2 release if your beans are fresh.
- At 0:45, pour the remaining 60g of hot water in a slow, controlled spiral. Aim to finish pouring by 1:30.
- Let the coffee draw down through the bed and onto the ice. It should finish dripping by 2:30 to 3:00.
- Swirl the server to fully melt the ice and integrate the brew.
- Pour into a chilled glass over fresh ice if you want the cup colder. Or drink direct from the server.
The first sip should taste like a slightly more concentrated, more aromatic version of an excellent hot pour-over. Bright, clear, sweet on the finish. Not dilute. Not bitter.
The Stats That Actually Matter
Here are the numbers you need to anchor this recipe in your head. Print this and tape it to the cabinet next to your kettle.
- 1:10 effective ratio: 20g coffee, 200g total liquid (100g hot water + 100g ice).
- Bean dose: 20g (for a single 02 V60 brew). Philocoffea's shop scales to 50g.
- Hot water: 100g (50% of total liquid).
- Ice: 100g (the other 50% of total liquid). Use weighed ice, not "a handful."
- Brew time: 3 minutes 30 seconds, end to end. Tighter than the 4:6 hot recipe.
- Grind: Medium-fine. On a Comandante C40, that's roughly 18-20 clicks. On a 1Zpresso JX-Pro, around 2.0 to 2.2 turns.
- Water temperature: 92 degrees C. Same as Kasuya's hot 4:6 recipe — there's a reason he doesn't change this. Pour-Over Brewing Temperature Decoded: Why Tetsu Kasuya Picks 92°C
- Bloom water amount: 40g, or 2x the dose. Twice the bloom multiplier of his standard hot recipe (which uses 60g for 20g coffee). Less water at bloom because total water budget is smaller.
- Philocoffea shop ratio: 1:6:6, meaning 50g coffee to 300g hot water to 300g ice. Stronger cup, designed for cafe service over big ice.
Why Hot-Bloom for Iced Coffee?
The whole reason this method exists comes down to one chemistry fact. The aromatic compounds that make great coffee great — esters, aldehydes, terpenes, the molecules that smell like jasmine, peach, blueberry, bergamot — only release in volume above about 80 degrees C. Cold water cannot drag them out of the bean efficiently. That's why traditional cold brew tastes "smooth" but also tastes flat. The smoothness is the absence of acid, but it comes paired with the absence of aroma.
Kasuya's insight: do the aromatic extraction phase hot, then immediately quench it. The hot bloom and main pour pull the aromatics. The ice, sitting in the server, locks them in by flash-chilling the brew the moment it leaves the dripper.
In a 2024 Standart Japan editorial on iced coffee technique, the editors framed it like this: "Kasuya is not making cold brew. He is making hot coffee that arrives cold." That's the right frame. The brewing itself is a hot extraction. The chilling is a separate, downstream event that happens to occur in the same vessel.
James Hoffmann, the British coffee writer and 2007 World Barista Champion, has called the broader Japanese iced approach "still the highest-fidelity way to drink iced coffee" in his YouTube comparisons. He's referring to the family of methods Kasuya's recipe sits inside.
Tetsu Kasuya 4:6 Method: Decoded for English Brewers
Tetsu Kasuya Iced vs Japanese Cold Brew (Mizudashi)?
This is the comparison that confuses people most. Both are "Japanese." Both are cold. They are not the same drink, and they are not made the same way.
Mizudashi (水出し) is full immersion cold brew. Coarsely ground coffee sits in cold water for 8 to 12 hours, usually in a Hario Mizudashi pot or a Toddy-style brewer. No heat ever touches the coffee. The result is low acidity, heavy body, chocolatey notes, and almost no top-end aromatics. Hario Mizudashi Cold Brew Review: Japan's Iced Coffee Standard
Kasuya's iced method is hot pour-over with the ice acting as both diluent and chiller. Coffee sees 92 degrees C for the entire 3 minutes of the brew. The result is high acidity, light-medium body, fruity and floral notes, and aromatics fully present.
Side by side, they don't taste like variations of the same drink. They taste like different beverages entirely. Mizudashi is what you want at 7am with breakfast. Kasuya's iced is what you want at 3pm when you need clarity.
The other thing to know: mizudashi takes 8 hours of patience. Kasuya's recipe takes 3 minutes 30 seconds. If you forget to set up cold brew the night before — and you always do — Kasuya's method is the one that saves you.
Common Mistakes With This Method?
After teaching this recipe to maybe a hundred home brewers and watching where it goes wrong, here are the five mistakes that account for 80% of bad cups.
1. Putting the ice in the dripper. This is the most common error. The ice goes in the server, below the dripper. If you put ice in the bed of grounds, you ruin the hot extraction phase entirely and end up with a weird half-cold-brew that tastes like neither method.
2. Using a coarse grind. Because the total brew time is shorter than a hot pour-over (3:30 vs 4:00 for a hot V60), and because half your water is being delivered cold via melting ice, you need a slightly tighter grind to compensate. Most brewers default to their hot setting and end up with sour, under-extracted iced coffee.
3. Over-pouring at bloom. Kasuya uses 40g of hot water at bloom for a 20g dose. That's a 2:1 ratio. People used to the 4:6 method (which uses 3:1 at first pour) over-pour and saturate the bed before the bloom phase finishes its CO2 release.
4. Not weighing the ice. "A handful of ice" is not a recipe. Different cube sizes mean different surface areas and different melt rates. If you weigh 100g of ice and your server arrives with a beverage at 130g instead of the expected 150g, your ice melted incompletely and your final dilution is off.
5. Drinking it on top of more ice. This is taste preference, but if you pour the finished brew over a fresh glass of ice, you re-dilute the cup and lose the careful balance Kasuya engineered. Drink it straight from the server, or pre-chill your glass without adding ice.
How Does It Compare to Other Iced Methods?
Here is the comparison table this article was waiting to drop. Five iced coffee methods, side by side.
| Method | Brew Time | Coffee Dose | Ice Ratio | Taste Profile | Equipment |
|---|---|---|---|---|---|
| Kasuya hot-bloom-then-ice | 3:30 | 20g | 1:1 (water:ice by weight) | Bright, aromatic, sweet finish, medium body | V60, gooseneck, scale, server |
| Japanese mizudashi cold brew | 8-12 hours | 50-60g per liter | No ice during brew, served over ice | Low acid, heavy body, chocolate, mellow | Hario Mizudashi pot or Toddy |
| American immersion cold brew | 12-24 hours | 75-100g per liter | No ice during brew, often diluted 1:1 with water/milk | Sweet, syrupy, low acid, can taste flat | French press or jar |
| Aeropress iced | 1:30-2:00 | 17-18g | 1:1 with served ice | Concentrated, sweet, fast and forgiving | Aeropress, ice |
| Flash-chill V60 | 3:00-4:00 | 20g | All-ice server, full hot water pour | Very bright, similar to hot V60 but cooler, can be acidic | V60, gooseneck, scale, server |
The two methods that look most similar on paper — Kasuya's recipe and flash-chill V60 — actually diverge significantly in practice. A pure flash-chill recipe uses the full hot-water amount (say 300g for 20g coffee) and dumps it all over a server filled with enough ice to chill the entire batch. Kasuya's version reduces the hot water to half and lets the ice itself contribute the other half to the dilution. Net result: stronger extraction per gram of hot water, less risk of over-extraction at the end of the pour, and a cup that holds together better as the ice melts further during drinking.
Hario V60 vs Kalita Wave vs Origami: 2026 Decision Guide
Variations: Philocoffea Shop Recipe vs Home Recipe
Tetsu Kasuya's actual coffee shops — Philocoffea has locations in Funabashi (the original) and Omotesando in Tokyo — run a slightly different recipe than what he teaches home brewers.
Shop recipe (1:6:6): 50g coffee, 300g hot water, 300g ice. Total ratio 1:12 effective. Brewed on a larger flat-bottom or wave-style dripper for cafe consistency. The shop version is more concentrated per gram of hot water (1:6 instead of 1:5) but ends up at similar effective dilution because of the heavier ice load.
Home recipe (1:5 hot, 1:10 effective): 20g coffee, 100g hot water, 100g ice. The version we walked through above.
Single-serve micro recipe (1:5 hot, 1:10 effective, scaled small): 12g coffee, 60g hot water, 60g ice. Use this if you have a V60 01 dripper or are brewing for one small cup.
The math holds at every scale. What matters is that the hot water is half the total liquid and that you grind a touch tighter than your hot V60 baseline. Tetsu Kasuya's 4:6 Method Book Translated: Beyond the Recipe
Bean Selection: What Works Best in This Recipe?
Not every coffee shines as iced. Here's what we've found across maybe 200 brews of this method.
What works: Light to medium roast Ethiopian, Kenyan, Colombian, and Costa Rican beans. Anything with bright acidity and floral or fruit-forward aromatics. The hot bloom pulls those notes out and the ice locks them in. A great natural-process Ethiopian — say, a Yirgacheffe at 14 days off-roast — is almost too pleasant in this method.
What doesn't work: Dark roasts. The smoke and bitterness compounds extract very efficiently in hot water and don't get cut by dilution the way fruit acids do. A dark roast in this recipe tastes like burnt rubber over ice. Use mizudashi or commercial cold brew for dark roast iced.
Roast date: 7 to 21 days post-roast is the window. Too fresh and you get aggressive CO2 at the bloom. Too old and you've lost the volatile aromatics this entire method exists to capture.
Philocoffea sells Kasuya's own roasted beans through their English-language web shop, and they specifically tag certain lots as "ice brew recommended." Worth trying if you want to taste the recipe with the coffee it was developed against.
What Tetsu Kasuya Says About This Method
In a 2023 episode of Patrik Rolf's Coffee with April podcast — the episode is titled "Brewing New V60 Methods with Tetsu Kasuya" — Kasuya explains his philosophy on iced coffee in plain terms. Paraphrased from the English subtitles:
"I want iced coffee to taste like coffee. Not like a cold drink that happens to have coffee in it. The bloom has to be hot or you cannot taste the coffee."
That's the design constraint of the entire recipe in one sentence. Hot bloom or it's not coffee.
He also wrote in his 2024 English-translated book on V60 brewing (published by Philocoffea and available through their web shop in print) that the ratio of hot water to ice was the single variable he tested most when developing the method. He landed on 1:1 because at that ratio, "the temperature of the final cup is consistent regardless of starting bean temperature, and the dilution is correct without further adjustment."
Translation: he tuned the recipe so that you, the home brewer, don't have to make any decisions about temperature or dilution after the brew finishes. Just brew, swirl, drink.
FAQ
Q: Can I use a Kalita Wave instead of a V60? A: Yes. The Kalita's flat bottom and slower drawdown actually work nicely with this recipe — the longer contact time compensates for the lower bed temperature as ice cools the server below. Use the same dose, water, and ice. You may want to grind one click coarser to keep total brew time under 4 minutes.
Q: Does the water temperature really need to be 92 degrees C exactly? A: Within plus or minus 2 degrees, yes. Below 88C and the bloom doesn't release aromatics fully. Above 96C and you over-extract bitter compounds in the short brew window. If you don't have a temperature-controlled kettle, boil and let sit 30 to 45 seconds before pouring.
Q: Can I make this with a regular drip coffee maker? A: Not really. The recipe depends on controlling the bloom phase separately from the main pour, and on weighing both water and ice. A drip machine can't separate bloom from pour. If you want a machine-friendly Japanese iced coffee, look at flash-chill V60 instead — it's more forgiving and works in a Bonavita or Technivorm with ice in the carafe.
Q: How long does the finished brew keep in the fridge? A: Drink within 2 hours of brewing for full aromatic complexity. The whole point of this method is preserving volatile aromatics, and those evaporate even from a sealed container over time. If you want a brew you can store for days, make mizudashi instead. It's designed for that.
Q: Why does my version taste sour? A: Almost always one of three things. Grind is too coarse (tighten by 2 clicks), water temp is too low (verify with a thermometer), or you skipped the 45-second bloom (start the timer and respect the bloom phase). Sour means under-extracted, which means hot phase didn't finish its job before the ice took over.
The One-Line Summary
Tetsu Kasuya's iced coffee recipe is what happens when a World Brewers Cup champion takes the question "how do I make great iced coffee at home in three minutes" seriously. Hot bloom for aromatics. Ice in the server for chill and dilution. 1:1 hot-water-to-ice. 1:10 effective ratio. 92 degrees C. Done in three and a half minutes.
The method is simple enough to memorize but specific enough that the details matter. Weigh the ice. Grind a touch fine. Don't put ice in the dripper. Drink it straight from the server.
If you've been making cold brew because you thought iced pour-over had to be either flash-chilled-and-thin or watered-down-and-bitter, this recipe is the answer to a question you didn't know you were asking. It's the iced coffee a champion brewer drinks at his own shop. Now you can drink it at home.
External Sources
- Tetsu Kasuya's English Philocoffea blog: "Coffee Basics: How to Make Cold & Ice Brew Coffee" — en.philocoffea.com/blogs/blog/cold-ice-brew-coffee-recipe-tips
- Kurasu Kyoto's English translation of Kasuya's ice brew recipe — kurasu.kyoto/blogs/kurasu-journal/tetsu-kasuya-ice-brew-coffee-english
- Coffee with April Episode 74 with Tetsu Kasuya (YouTube) — covers his iced and hot V60 methods on camera
- Standart Japan magazine — quarterly print publication covering Japanese specialty coffee culture
- Sprudge.com feature coverage of Philocoffea Omotesando opening
- Philocoffea English shop — en.philocoffea.com — books, beans, and equipment from Kasuya's roastery
-- The Japanese Coffee Gear Team
META_DESCRIPTION: Tetsu Kasuya's iced coffee recipe translated: 20g coffee, 100g hot water, 100g ice, 92C, 3:30 brew. Hot-bloom-then-ice method explained.