Why is the blooming stage necessary during pour-over brewing?

Roasted coffee beans contain trapped carbon dioxide gas. Pouring 2 to 3 times the bean weight in hot water and pausing for 30 to 45 seconds causes the coffee bed to swell and degas. Removing this gas allows water to penetrate the cell structure evenly without turbulent air channeling.

Why did I pour 300ml of water but only got 260ml of coffee in my cup?

Dry coffee grounds act like sponges, absorbing approximately 2.0 to 2.2 times their weight in water (known as water retention). An 18g dose of coffee retains roughly 36 to 40ml of liquid in the spent bed, leaving about 260ml in your server.

How do I fix coffee that tastes excessively sour or excessively bitter?

Sour coffee indicates under-extraction; grind finer, increase water temperature by 2°C, or lengthen brew contact time. Bitter coffee indicates over-extraction; grind coarser, drop water temperature, or use a slightly shorter ratio (e.g., from 1:17 down to 1:15).

Why is espresso brewed at 1:2 while pour-over is brewed at 1:16?

Espresso uses 9 bars of mechanical pressure to rapidly extract solubles in 25 to 30 seconds into an intense concentrate (8% to 12% TDS). Pour-over relies strictly on gravity over 3 minutes to produce a ready-to-drink beverage at 1.2% to 1.4% TDS.

What is the difference between immersion and drip cold brew?

Immersion cold brew soaks coarse grounds in cold water inside a jar for 12 to 18 hours, yielding a sweet, heavy-bodied brew. Drip (Dutch) cold brew passes slow chilled drips through a tower bed over 4 to 8 hours, delivering lighter body with striking aromatic complexity.

Coffee Brewing Golden Ratio & Water Dose Calculator

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Calculate dry coffee dose, total water, and multi-stage pour schedules for pour-over, Chemex, French press, and cold brew.

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Coffee Brewing Golden Ratio Calculator

Calculate dry coffee dose, water volume, and multi-stage pour schedules

Brewing Method / Gear

Calculation Basis

Total Brewing Water (ml/g)

Brew Ratio (1 : N)

1 :

Brewing Recipe & Multi-Stage Pour

Dry Coffee Grounds

18.0 g

Ratio 1 : 16.7

Total Water Volume

300 ml (g)

Cumulative scale weight

Estimated Yield in Cup

~262 ml

Reflecting grounds water retention

Sequential Pouring Schedule

1단계: 뜸들이기 (Bloom)

45 ml

Wait 30-45s for degassing

2단계: 1차 주수

누적 172 ml

Spiral center to outer

3단계: 2차 마무리 주수

누적 300 ml

Remove dripper when drained

Water Temp91~94°C (196~201°F)

Contact Time2:30 ~ 3:30 min

Grind SizeMedium (600~800μm)

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Coffee Brewing Golden Ratio, Extraction Yield, & Pour Guide

In specialty coffee and manual pour-over brewing, the single most critical variable determining flavor profile is the 'Brew Ratio'—the exact mathematical relationship between dry coffee grounds and brewing water.

The Specialty Coffee Association (SCA) 'Golden Cup' standard mandates a brew ratio between 1:15 and 1:18 (specifically 55g to 60g of dry coffee per 1,000ml of water). This target balance avoids both the sour, hollow profile of under-extraction and the astringent, bitter finish of over-extraction, achieving ideal Total Dissolved Solids (TDS) and Extraction Yield.

This professional coffee calculator supports pour-over (V60, Kalita, Chemex), espresso, French press, Aeropress, and cold brew. It calculates total water, dry dose, blooming volume, and step-by-step multi-stage pouring schedules based either on target cup volume or available bean weight.

SCA Golden Cup Extraction Yield & TDS Formulation

The mathematical interplay governing dissolved coffee solubles, liquid brew weight, and dry mass efficiency.

Coffee Ratio & Extraction MathematicsMathematical Formulation

Total Water Mass (ml or g) = Dry Coffee Dose (g) × Brew Ratio Required Dry Dose (g) = Total Water Mass (ml) / Brew Ratio Bloom Water Volume (ml) = Dry Coffee Dose (g) × 2.5 ~ 3.0 Extraction Yield (%) = [Brewed Beverage Weight (g) × TDS (%)] / Dry Coffee Dose (g) * SCA Golden Cup Target: TDS 1.15% - 1.45% | Extraction Yield 18.0% - 22.0%

Spent coffee grounds retain roughly twice their weight in absorbed water (2.0g to 2.2g of water per 1.0g of coffee grounds). Pouring 300ml of water over 18g of coffee yields approximately 264ml of final liquid beverage.

Brewing a 300ml pour-over on a V60 using the SCA Golden Ratio (1:16.67)

Dry Coffee Dose Calculation300 ml / 16.6718.0 g coffee

Bloom Water Volume (30-45s)18.0 g × 2.545.0 ml bloom

First Stage PourPour up to half remaining targetCumulative 170 ml

Final Stage Finish PourPour up to final markCumulative 300 ml

👉 Using 18.0g of coffee with 300ml of water yields roughly 264ml of balanced specialty coffee.

Brewing Method Standards, Ratios, Grind Sizes, & Water Temperatures

Standard parameters across major brewing apparatuses according to specialty barista protocols

Brewing Method / Gear	Recommended Ratio	Grind Micron (μm)	Water Temperature	Total Contact Time	Flavor Characteristics
Pour-Over (Hario V60)	1 : 15 ~ 1 : 17	Medium (600~800μm)	90°C ~ 94°C / 194-201°F	2:30 ~ 3:30 min	Vibrant acidity, high clarity
Chemex (Thick Paper)	1 : 16 ~ 1 : 18	Medium-Coarse (800~1000μm)	92°C ~ 95°C / 198-203°F	3:30 ~ 4:30 min	Extremely clean, light body
Aeropress (Standard)	1 : 11 ~ 1 : 14	Medium-Fine (400~600μm)	85°C ~ 90°C / 185-194°F	1:30 ~ 2:00 min	Rich body, espresso-like strength
French Press (Immersion)	1 : 12 ~ 1 : 15	Coarse (1000~1200μm)	93°C ~ 96°C / 200-205°F	4:00 ~ 5:00 min	Heavy mouthfeel, aromatic oils
Cold Brew (Concentrate)	1 : 5 ~ 1 : 8	Extra Coarse (>1200μm)	Cold / Room Temp (4-15°C)	12 ~ 18 hours	Low acidity, chocolate sweetness
Cold Brew (Ready-to-Drink)	1 : 10 ~ 1 : 12	Coarse (1000μm)	Chilled Water (4-10°C)	16 ~ 20 hours	Smooth, drinkable over ice directly
Espresso (Standard Double)	1 : 2 ~ 1 : 2.5	Fine (200~300μm)	91°C ~ 94°C / 196-201°F	25 ~ 32 seconds	Thick crema, high TDS (8-12%)
Espresso (Ristretto)	1 : 1 ~ 1 : 1.5	Fine (200~300μm)	92°C ~ 94°C / 198-201°F	20 ~ 25 seconds	Maximum sweetness, zero bitterness

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How to Use

11. Select Brewing Method

Choose your brewer (Pour-Over V60, Chemex, French Press, Aeropress, Cold Brew, or Espresso).

22. Choose Strength or Custom Ratio

Pick Mild (1:18), Golden Standard (1:16.67), Bold (1:15), or enter a custom brew ratio.

33. Choose Input Basis (Water vs Coffee)

Specify target beverage volume (ml or cups) or enter available dry bean weight in grams.

44. Review Multi-Stage Pour Schedule

Follow real-time calculations for bloom water (30-45s) and sequential multi-pour weight targets.

Everyday Coffee Brewing Scenarios

Tailoring recipes for single morning mugs, multi-cup weekend mornings, and batch cold brew

Morning Commuter Travel Mug (350ml)

Dosing 21g of coffee with 350ml of 93°C water at 1:16.67 ratio produces a rich 300ml mug with sparkling floral clarity.

Weekend Chemex for Two Guests (600ml)

Using 36g of medium-coarse grounds and 600ml of water with an initial 90ml bloom gives two full cups of pristine coffee.

Weekly Cold Brew Concentrate Batch (1L)

Steeping 150g of coarse grounds in 1,000ml of cold filtered water (1:6.67) for 16 hours produces 750ml of rich concentrate to dilute 1:1 with milk or water.

Japanese Iced Pour-Over (Flash Brew)

Placing 120g of ice in the server and brewing with 20g coffee and 180ml hot water (1:9 ratio) locks in volatile aromatics instantly.

💡 Barista Pour-Over Precision Guidelines

✓ Use a 0.1g Digital Scale with Timer

Volumetric scoops introduce up to 20% variance due to bean density differences. Always measure beans and water by mass in grams.

✓ Match Roast Level to Water Temperature

Light roasts benefit from 93-95°C water to extract dense sugars; dark roasts should be brewed cooler (88-90°C) to curb bitterness.

✓ Rinse Paper Filters Prior to Dosing

Rinsing preheats your ceramic/glass dripper and washes away dry paper pulp flavors into the waste basin.

⚠️ Common Pitfalls & Mistakes to Avoid

❌ Allowing the Bloom to Sit Past 60 Seconds

✅ Extending the bloom beyond 45 seconds cools the coffee slurry, impeding smooth extraction during subsequent pours.

❌ Pouring Hot Water Directly onto Filter Paper Walls

✅ Direct wall pouring induces bypass channeling where water escapes into the server without extracting coffee grounds.

❌ Squeezing the Spent Filter at the End of Brewing

✅ The final drips hold concentrated astringent polyphenols; pull the dripper away as soon as the water bed drains.

Frequently Asked Questions (FAQ)

Expert answers to the most frequently asked questions and edge cases.

6 Q&As

It means using 1 part coffee to 16.67 parts water by weight. In metric terms, that equals exactly 60 grams of coffee per 1,000 milliliters (1 liter) of water, the benchmark standard established by the Specialty Coffee Association.

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