Iced Coffee Ratio
Calculator
Cold brew, Japanese iced coffee, and hot brew over ice. Get exact measurements in grams, cups, and tablespoons with a step-by-step brew guide for your method.
Iced Coffee Ratio Calculator
Choose your method and get exact measurements
Iced Coffee Ratio Quick Reference
All ratios by weight. For water: 1g = 1ml. Coffee is weighed separately from water in all methods.
Cold Brew by Container Size
| Container | Batch Volume | RTD (1:7) | RTD (1:8) | Concentrate (1:5) | Tablespoons (RTD) |
|---|---|---|---|---|---|
| 16 oz / 500 ml | 500 ml | 71 g | 63 g | 100 g | ~14 tbsp |
| 32 oz / 946 ml | 946 ml | 135 g | 118 g | 189 g | ~27 tbsp |
| 1 liter pitcher | 1000 ml | 143 g | 125 g | 200 g | ~29 tbsp |
| 64 oz / 2 qt | 1893 ml | 270 g | 237 g | 379 g | ~54 tbsp |
| 1 gallon (party) | 3785 ml | 541 g | 473 g | 757 g | ~108 tbsp |
Japanese Iced Coffee by Final Drink Size
| Final Drink | Ratio | Coffee | Hot Water (brew) | Ice Weight | Tablespoons |
|---|---|---|---|---|---|
| 240 ml (8 oz) | 1:12 | 20 g | 132 ml hot | 108 g | ~3.5 tbsp |
| 300 ml (10 oz) | 1:12 | 25 g | 165 ml hot | 135 g | ~4 tbsp |
| 360 ml (12 oz) | 1:12 | 30 g | 198 ml hot | 162 g | ~5 tbsp |
| 480 ml (16 oz) | 1:12 | 40 g | 264 ml hot | 216 g | ~7 tbsp |
| 300 ml (10 oz) | 1:15 | 20 g | 165 ml hot | 135 g | ~3.5 tbsp |
Why Iced Coffee Uses More Coffee Than Hot Brew
Cold water extracts coffee compounds less efficiently than hot water. This is not a limitation; it is chemistry. At temperatures above 90 C, water molecules have enough energy to pull most of the soluble compounds out of ground coffee in 3 to 5 minutes. At 4 C or 20 C, the same process takes 12 to 24 hours, and even then, some compounds that extract readily in hot water remain mostly undissolved.
Cold brew needs roughly 1.5 to 2 times more coffee per volume of water than a standard hot brew to achieve a similar perceived strength. A good drip coffee might use a 1:15 to 1:17 ratio. Ready-to-drink cold brew uses 1:7 to 1:8, and cold brew concentrate uses 1:4 to 1:5. The higher coffee concentration also gives cold brew its characteristic body and richness that water-forward ratios cannot produce.
For Japanese iced coffee and hot-brew-over-ice methods, you are still brewing with hot water, so the extraction efficiency is the same as standard hot brewing. The difference is that you account for the ice volume as part of your total water: you brew at approximately double strength over ice that will melt and dilute the coffee to your target ratio.
Cold Brew Concentrate vs Ready-to-Drink: Which Should You Make?
The choice between concentrate and ready-to-drink cold brew comes down to fridge space, serving flexibility, and shelf life. Neither is inherently better; they just serve different use cases.
Ready-to-drink cold brew (1:7 to 1:8)
You pour it directly from the fridge into a glass of ice and drink. No dilution step. For a 32 oz batch, this fills the jar with 135g of coffee and 946ml of water, strains it, and gives you about 800 to 850ml of drinkable cold brew after the grounds absorb some water. Lasts 7 to 10 days in an airtight jar. Takes up the full jar volume in fridge space.
Cold brew concentrate (1:4 to 1:5)
You brew a smaller but denser batch and dilute it before each serving. A 32 oz jar of concentrate gives you 60 to 70 servings when diluted 1:1, compared to about 4 to 5 servings from a 32 oz ready-to-drink batch. Concentrate takes up less fridge space, lasts up to 2 weeks, and lets you customize each serving with water, milk, oat milk, or sparkling water. The trade-off is one extra step per serving.
Ready-to-Drink (1:7 or 1:8)
Pour and serve. No dilution needed. Best for consistent daily drinkers who want a fixed strength. Less batch efficiency than concentrate.
- Shelf life: 7 to 10 days
- Serving: pour over ice, no dilution
- Best for: daily fixed-strength drinkers
- Space: full jar volume
Concentrate (1:4 or 1:5)
Dilute before serving. Maximum batch efficiency. Customize each serving. Longer shelf life. One extra step per serving.
- Shelf life: up to 2 weeks
- Serving: dilute 1:1 with water or milk
- Best for: flexibility, milk drinks, meal prep
- Space: 50% less fridge volume per serving
How Long Should You Steep Cold Brew? The Temperature and Time Guide
Steep time and temperature are linked. As temperature rises, extraction speeds up. Cooler temperatures extract more slowly and produce a slightly cleaner, smoother result. The risks at each extreme are under-extraction (weak, grassy, slightly sour) and over-extraction (bitter, harsh, overly strong).
The 18 to 24 hour fridge steep has become the standard recommendation because it sits comfortably between both risks. Cold water extracts slowly enough that an extra 2 to 4 hours in the fridge rarely causes over-extraction, making it forgiving for home brewers who are not precise about timing. Room temperature steeping is faster but narrower: an extra 3 hours at 22 C can push a batch from ideal to over-extracted, particularly with a medium grind.
Both methods should use a coarser-than-usual grind. The long contact time makes fine or medium grinds prone to over-extraction even at cold temperatures.
How Japanese Iced Coffee Works and Why It Tastes Different from Cold Brew
Japanese iced coffee brews hot coffee directly onto a bed of ice in the serving vessel. The weight of the ice is calculated to be exactly the remaining water in the recipe after accounting for the hot brew portion. When the hot coffee hits the ice, the ice melts rapidly, chilling the brew to near zero and diluting it simultaneously. The rapid chilling locks in volatile aromatic compounds that would otherwise evaporate as the coffee cools slowly in a pot.
The result is coffee that is cold but still tastes bright, aromatic, and fruit-forward. Cold brew, by contrast, never extracts those volatile compounds at all because they require high-temperature water to dissolve. Japanese iced coffee is not better or worse than cold brew; they produce genuinely different flavor profiles from the same beans.
What Grind Size Should You Use for Cold Brew?
Extra-coarse is the standard for cold brew immersion. Think of the texture you use for a French press, and then go one or two notches coarser. The particles should be visible as distinct chunks, not powder or fine sand. The reason for such a coarse grind is the long steep time: with 18 to 24 hours of contact, even the slower cold extraction has enough time to pull bitter compounds from finer grinds that it would never reach in a 4-minute French press.
Pre-ground coffee from the supermarket is usually ground at a medium or drip setting, which is significantly finer than ideal for cold brew. It will work in a pinch and produce drinkable cold brew, but the result will typically be slightly more bitter and less clean than the same coffee ground extra-coarse on a burr grinder.
For Japanese iced coffee and hot-brew-over-ice, use the same grind you would use for the pour-over or drip method you are working with. The grind follows the brewing method, not the serving temperature. Japanese iced V60 uses a medium-fine V60 grind.
How Long Does Cold Brew Last and How to Store It
Strained cold brew (grounds removed) lasts 7 to 10 days in an airtight glass container in the refrigerator. Cold brew concentrate, because of its higher coffee concentration, lasts up to 2 weeks. The difference is that concentrate has a higher TDS (total dissolved solids) content, which creates a mildly hostile environment for the microorganisms responsible for spoilage.
The container matters. Glass jars with tight-fitting lids (mason jars, swing-top glass bottles) keep cold brew fresh longer than open-top jugs or plastic containers. Oxygen is the enemy: once strained cold brew is exposed to air repeatedly, it oxidizes and takes on a flat, slightly metallic flavor faster than properly sealed batches.
Signs that cold brew has passed its prime: sourness that was not there in the first few days, a slight off smell, or visible cloudiness that was not present when you first strained it. Fresh cold brew should smell rich and slightly sweet. Never drink cold brew with any mold visible anywhere in the container, even if it looks confined to the lid.
Cold Brew and Iced Coffee Troubleshooting
Cold Brew Equipment Worth Having
You can make cold brew with a mason jar and a coffee filter. This is the gear that makes it easier and more consistent.
Frequently Asked Questions About Iced Coffee Ratios
What is the best coffee to water ratio for cold brew?
+For ready-to-drink cold brew: 1:7 or 1:8 by weight. For 946ml (32 oz), that is 118 to 135g of coarsely ground coffee. For cold brew concentrate: 1:4 or 1:5. A 1:5 concentrate diluted 1:1 gives an effective ratio around 1:10. Start at 1:7 if you are unsure, taste after straining, and adjust by 1 ratio point next batch.
Why does cold brew use more coffee than hot brew?
+Cold water extracts less efficiently than hot water. At refrigerator temperature, the same compounds that dissolve in 3 to 5 minutes at 93 C take 12 to 24 hours to extract, and some compounds never fully dissolve in cold water. Cold brew needs 1.5 to 2 times more coffee per volume than hot brew to achieve comparable perceived strength.
What is cold brew concentrate and how do you dilute it?
+Cold brew concentrate is brewed at 1:4 or 1:5 ratio, too strong to drink straight. Dilute 1:1 with water or milk before serving. A 1:5 concentrate diluted 1:1 gives an effective 1:10 final ratio. Concentrate lasts up to 2 weeks in the fridge versus 7 to 10 days for ready-to-drink, and takes half the fridge space per serving.
What is Japanese iced coffee?
+Japanese iced coffee brews hot coffee directly onto ice. The ice is calculated to be exactly the remaining water in the recipe, so as it melts, it dilutes the double-strength brew to your target ratio. Ready in 5 minutes, brighter and more aromatic than cold brew. Best made with a pour-over dripper like a V60 or Chemex.
How long should I steep cold brew coffee?
+Fridge (4 C): 18 to 24 hours. Room temperature (18 to 22 C): 12 to 16 hours. The fridge method is safer and more consistent. Room temperature is faster but has a narrower window before over-extraction. Always strain after reaching your target time regardless of temperature.
What grind size should I use for cold brew?
+Extra-coarse: coarser than French press. Visible individual particles, similar to coarse sea salt. Finer grinds over-extract during the long steep time and produce a bitter, astringent cold brew. Pre-ground supermarket coffee works but is usually too fine; expect slightly more bitterness than fresh-ground extra-coarse.
How do I make iced coffee that does not taste watered down?
+Brew at 1.25x to 1.5x stronger than usual before pouring over ice, or use the Japanese iced coffee method where ice volume is pre-calculated. Coffee ice cubes (freeze leftover coffee or cold brew) also work: as they melt, they add flavor instead of diluting. An insulated tumbler slows ice melt significantly.
Can I use milk instead of water in cold brew?
+Yes, but only in the fridge (never at room temperature with milk). Use a lower ratio like 1:4, steep 8 to 12 hours in the fridge. The result is creamy and naturally sweet. More common approach: brew standard water-based concentrate and dilute each serving with milk or oat milk instead of water.
How much coffee do I need for a 32 oz mason jar of cold brew?
+At 1:7 ratio: about 135g (27 tablespoons, or roughly 1 and three-quarter cups of coarse-ground coffee). At 1:8: about 118g (24 tablespoons). For 1:5 concentrate: about 189g. The jar will not hold everything at once for a full cold brew batch; use a 32 oz jar for about 850 to 900ml of actual batch to leave room for the grounds.
How long does cold brew last in the fridge?
+Ready-to-drink: 7 to 10 days in an airtight glass container. Concentrate: up to 2 weeks. Once diluted with milk: 3 to 5 days. Signs it has turned: sour smell, off taste, or visible cloudiness not present when freshly strained. Glass with airtight seal keeps it fresh longer than plastic.
What is the difference between cold brew and iced coffee?
+Iced coffee is hot-brewed coffee cooled and served over ice. Cold brew steeps in cold water for 12 to 24 hours with no heat. Cold brew has 15 to 67 percent less acidity than hot brew, tastes sweeter and smoother, and lacks the bright fruit notes that hot extraction produces. Iced coffee is brighter, more acidic, and ready in minutes. Neither is better; they taste genuinely different from the same beans.
Five Cold Brew Habits That Produce a Better Cup
Weigh your coffee every batch
Tablespoon measurements for coarse coffee are inconsistent. A level tablespoon of extra-coarse coffee can weigh anywhere from 4.5g to 6g depending on the bean size and how loosely it is ground. Over a 32 oz batch, that variability adds up to 30 to 40g of coffee difference, which shifts your effective ratio by a full point. A kitchen scale accurate to 1g is a $10 to $15 investment that makes every batch consistent.
Taste the concentrate before diluting
Fresh cold brew concentrate (before dilution) should taste intense, sweet, and slightly syrupy. It should not taste bitter, astringent, or sour. If the concentrate tastes off before dilution, no amount of dilution will fix it. Tasting the concentrate immediately after straining tells you the quality of the batch and guides how much to dilute it per serving.
Strain twice for clarity
A single pass through cheesecloth or a metal filter leaves fine particles that settle at the bottom of the jar and contribute to bitterness if stirred up. A second pass through a paper coffee filter (set in a fine mesh strainer over the jar) takes an extra 5 to 10 minutes but produces a noticeably cleaner, clearer cold brew. The difference is visible and tasteable.
Use the Japanese iced method for light roasts
Light roasts with fruity, floral, or complex acidic notes often taste muted and dull as cold brew. The high-temperature extraction required to unlock their bright compounds does not happen in cold water. If you have a light roast that you love as a hot pour-over, make it as Japanese iced coffee instead. The flavor is far more representative of what the bean can do than cold brew from the same beans.
Batch for the week on Sunday
Cold brew that has had 24 hours to settle and chill properly tastes noticeably better than cold brew drunk immediately after straining. Making a full batch on Sunday evening means Monday through Thursday you are drinking cold brew that has had time to settle, and you are not rushing the process during a weekday morning when you actually want the coffee.
Starting Point for Any Iced Coffee Method
For cold brew: 135g of coarsely ground coffee in 946ml (32 oz) of cold water for 18 hours in the fridge. Strain twice. Serve over ice. This is a 1:7 ratio and produces a full-flavored, slightly strong cold brew that dilutes nicely as the ice melts. If it is too strong, try 1:8 next time. If it is too weak, try 1:6. The calculator above handles the math for any batch size once you know your target ratio.