Aqueous Stoichiometry & Burr Granulometry Workbench

Specialty Coffee Water Mineral (GH / KH Alkalinity) & Brew Method Grind Micron Matrix

Why does a championship Geisha or washed Kenyan pour-over taste sparkling, juicy, and floral at a specialty cafe yet turn flat, chalky, or harshly sour at home? Water is the chemical solvent of coffee extraction, governed by two distinct ionic parameters expressed in parts per million as Calcium Carbonate equivalents (ppm as CaCO3, molar mass 100.087 g/mol): General Hardness (GH, the sum of divalent Mg²⁺ and Ca²⁺ cations that bind and extract flavor compounds) and Carbonate Alkalinity (KH, the concentration of bicarbonate HCO3⁻ ions that buffer hydrogen protons H⁺ and control perceived cup acidity). Use the interactive DIY water remineralization and grind micron workbench plus the three complete static HTML reference matrices below to formulate exact brewing water and particle distributions.

1. Specialty Coffee Association (SCA) Water Quality Target Matrix (Static HTML Reference)

The table below lists the official Specialty Coffee Association (SCA) Water Quality Handbook target specifications alongside modern light-roast filter and scale-safe espresso boiler benchmarks. Notice that both General Hardness (GH) and Total Alkalinity (KH) are standardized to ppm as CaCO3 equivalents (`100.087 g/mol`) so divalent and monovalent ions can be compared on an equal molar charge basis.

Water Chemistry Parameter	SCA Target Baseline	SCA Acceptable Window	Modern Light-Roast Filter Sweet Spot	Scale-Safe Espresso Boiler Window	Brewing & Equipment Impact Outside Range
General Hardness (`GH` as `CaCO3`)	`68 ppm` (`4 gpg`)	`50 – 175 ppm`	`55 – 95 ppm` (`70%+` from `Mg²⁺`)	`35 – 65 ppm` (Keep `Ca²⁺` low)	`< 35 ppm` yields weak body/extraction; `> 120 ppm` with high `Ca²⁺` precipitates `CaCO3` boiler scale.
Carbonate Alkalinity (`KH` as `CaCO3`)	`40 ppm`	`40 – 75 ppm`	`20 – 40 ppm`	`40 – 55 ppm`	`< 15 ppm` leaves sour unbuffered proton spikes; `> 75 ppm` neutralizes fruity chlorogenic/citric acids into chalk.
Total Dissolved Solids (`TDS`)	`150 mg/L`	`75 – 250 mg/L`	`90 – 160 mg/L`	`85 – 145 mg/L`	`0 mg/L` distilled water corrodes brass/copper boilers and extracts harshly.
Aqueous `pH` (at `25°C`)	`7.00`	`6.50 – 7.50`	`6.60 – 7.20`	`6.80 – 7.40`	Remember: `pH` measures instantaneous `[H⁺]`, whereas `KH` measures acid-neutralizing capacity!
Sodium Ion (`Na⁺`)	`10 mg/L`	`< 30 mg/L`	`0 – 15 mg/L`	`0 – 18 mg/L`	Above `30 mg/L`, sodium imparts a savory, saline slickness; use `KHCO3` instead of `NaHCO3` for zero sodium.
Chloride Ion (`Cl⁻`)	`< 15 mg/L`	`< 30 mg/L`	`0 – 25 mg/L`	`< 20 mg/L` (304/316 SS Boiler Limit)	Elevated chloride (`> 35–50 mg/L`) causes stress-corrosion cracking and pitting in stainless steel espresso boilers at `125°C`.
Free Chlorine / Chloramine (`Cl2`)	`0.0 mg/L`	`0.0 mg/L`	`0.0 mg/L`	`0.0 mg/L`	Even `0.05 mg/L` chlorine reacts with coffee phenols to form medicinal trichloroanisole (`TCA`) off-odors.

2. Exact Stoichiometric Conversion Table for DIY Remineralization Salts (Static HTML)

Because `1.00 millimole per liter (mmol/L)` of divalent `Mg²⁺` or `Ca²⁺` equals **`100.087 ppm as CaCO3`** (`GH`), while `1.00 mmol/L` of monovalent `HCO3⁻` neutralizes `1.00 mmol/L` of `H⁺` and therefore equals **`50.043 ppm as CaCO3`** (`KH`, since `1 mol CaCO3` neutralizes `2 mol H⁺`: `CaCO3 + 2H⁺ → Ca²⁺ + CO2 + H2O`), the exact milligrams of food-grade salt required per liter of distilled water to add **`1.00 ppm as CaCO3`** are fixed by IUPAC atomic weights:

Food-Grade Mineral Salt (USP / FCC)	Chemical Formula & Molar Mass	Target Parameter Added	Exact Salt Mass per Liter for `+1.00 ppm as CaCO3`	Grams in `1.00 L` Stock Bottle for a `1,000 ppm as CaCO3` Concentrate
Epsom Salt (Magnesium Sulfate Heptahydrate)	`MgSO4·7H2O` (`246.47 g/mol`)	`+1.00 ppm GH` (`Mg²⁺` hardness; zero boiler `CaCO3` scale)	`2.4626 mg / L` (Adds `0.243 mg/L Mg²⁺` + `0.959 mg/L SO4²⁻`)	`2.463 g` per `1.00 L` distilled water (`1 mL` per `1 L` brew water = `+1 ppm GH`)
Calcium Chloride Dihydrate	`CaCl2·2H2O` (`147.01 g/mol`)	`+1.00 ppm GH` (`Ca²⁺` hardness; creamy heavy body)	`1.4688 mg / L` (Adds `0.400 mg/L Ca²⁺` + `0.708 mg/L Cl⁻` — watch `Cl⁻` limit!)	`1.469 g` per `1.00 L` distilled water (`1 mL` per `1 L` brew water = `+1 ppm GH`)
Baking Soda (Sodium Bicarbonate)	`NaHCO3` (`84.007 g/mol`)	`+1.00 ppm KH` (`HCO3⁻` carbonate alkalinity buffer)	`1.6787 mg / L` (Adds `1.219 mg/L HCO3⁻` + `0.459 mg/L Na⁺`)	`1.679 g` per `1.00 L` distilled water (`1 mL` per `1 L` brew water = `+1 ppm KH`)
Potassium Bicarbonate	`KHCO3` (`100.115 g/mol`)	`+1.00 ppm KH` (`HCO3⁻` buffer with `0 mg/L` sodium)	`2.0006 mg / L` (Adds `1.219 mg/L HCO3⁻` + `0.781 mg/L K⁺`)	`2.001 g` per `1.00 L` distilled water (`1 mL` per `1 L` brew water = `+1 ppm KH`)

3. Complete Specialty Brew Method Grind Micron (`D50`) & Parameter Matrix (Static HTML)

The static reference matrix below maps 12 specialty brewing methods from `150 µm` Ibrik to `1,100 µm` Cold Brew by their **median particle diameter (`D50` in micrometers / microns)**, recommended **unimodal vs. bimodal burr geometry**, **water-to-coffee ratio**, **slurry temperature**, and **target total contact time**:

Brewing Method	Target Median Grind (`D50` Microns)	Preferred Particle Distribution Profile	Standard Brew Ratio (Coffee : Water)	Brew Water Temp (Light / Med-Dark)	Target Contact / Drawdown Time
1. Ibrik / Cezve (Turkish Coffee)	`120 – 200 µm` (Powdery Flour)	High-fines bimodal (`> 40%` under `100 µm` for colloidal suspension)	`1 : 9` to `1 : 11`	`60°C` start → `94°C` foam rise	`2:00 – 2:45 min`
2. Traditional 9-Bar Espresso	`220 – 320 µm` (Fine)	Bimodal conical or traditional flat (`18%–25%` sub-100 µm fines for puck resistance)	`1 : 1.8` to `1 : 2.3` (Liquid yield)	`92°C – 94°C` / `88°C – 91°C`	`25 – 32 seconds`
3. 6-Bar Turbo Espresso (Modern Light)	`340 – 420 µm` (Coarse Espresso)	Low-fines unimodal flat burr (minimizes fines migration & channeling)	`1 : 2.5` to `1 : 3.2` (Liquid yield)	`93°C – 96°C`	`14 – 19 seconds`
4. Moka Pot (Stovetop Percolation)	`360 – 460 µm` (Fine-Medium)	Moderate bimodal (`1.5–2.0 bar` vapor pressure requires permeable bed)	`1 : 7` to `1 : 10`	Pre-heated `75°C–85°C` base water	`1:15 – 1:45 min`
5. AeroPress (Standard 2-Min Recipe)	`420 – 580 µm` (Medium-Fine)	Unimodal or balanced bimodal (immersion + gentle `0.3 bar` plunge)	`1 : 14` to `1 : 16.5`	`92°C – 96°C` / `85°C – 90°C`	`1:45 – 2:30 min`
6. Single-Cup Conical Pour-Over (V60-01/02)	`500 – 650 µm` (Medium-Fine)	High-uniformity unimodal flat or heptagonal hand burr (`narrow span`)	`1 : 16` to `1 : 17` (`15g : 250g`)	`94°C – 98°C` / `88°C – 92°C`	`2:30 – 3:15 min`
7. Flat-Bottom Dripper (Kalita Wave / Orea)	`600 – 750 µm` (Medium)	Unimodal flat burr (restricted bottom drain holes slow exit velocity)	`1 : 15.5` to `1 : 16.5`	`93°C – 96°C` / `88°C – 91°C`	`2:45 – 3:30 min`
8. SCA Cupping / Clever Steep-and-Release	`650 – 800 µm` (Medium-Coarse)	SCA Standard: `70%–75%` passing `#20` (`850 µm`) US mesh sieve	`1 : 18.18` (`8.25 g / 150 mL`)	`93°C – 94°C` (`200°F`) poured	`4:00 min` crust break
9. Chemex (Heavy Bonded Paper Pour-Over)	`700 – 880 µm` (Medium-Coarse)	Low-fines unimodal (thick 20–30% heavier paper chokes easily on fines)	`1 : 15.5` to `1 : 16.5` (`30g : 500g`)	`94°C – 97°C` / `89°C – 92°C`	`3:45 – 4:45 min`
10. Commercial / Home Batch Brewer (`1.0–2.0 L`)	`750 – 920 µm` (Coarse-Medium)	Unimodal flat burr (`60–90 mm` deep bed depth requires high permeability)	`1 : 16.5` to `1 : 18` (`60g : 1,000g`)	`92°C – 96°C` sprayhead	`4:30 – 6:00 min`
11. French Press (Hoffmann / Immersion)	`800 – 1,050 µm` (Coarse)	Low-fines unimodal or sifted (diffusion-limited; finer `750 µm` works if settled 8 min)	`1 : 15` to `1 : 16.5`	`94°C – 97°C` / `89°C – 92°C`	`4:00 – 8:00 min`
12. Immersion Cold Brew (`16–20 Hr` Steep)	`950 – 1,200 µm` (Extra Coarse)	Coarse low-fines cut (facilitates clean filtration after ambient steep)	`1 : 7` (Concentrate) to `1 : 14` (RTD)	`20°C` Ambient or `4°C` Fridge	`14 – 20 hours`

4. Carbonate Buffering (`pKa1 = 6.35`) and Cation Extraction Chemistry

To understand why `GH` and `KH` behave so differently in the cup, read our full derivations in Water Alkalinity (KH) and General Hardness (GH): How Bicarbonate Buffers Coffee Acidity, DIY Remineralized Coffee Water Recipes, Espresso Boiler Scale Chemistry & Langelier Index, and Flat vs. Conical Burrs: Bimodal vs. Unimodal Particle Distributions.