BrewmetricExtraction science in your pocket.
The specialized coffee extraction calculator for iOS. Design recipes with scientific precision, measure your extractions in real time, and save your complete history. All in a single app, with no subscriptions or internet connection required.
Scientific Precision
Utilizes industry-standard percolation and immersion formulas to ensure accurate calculations every single time.
Native & Offline
Built 100% for iOS. All your parameters, recipes, and measurements are stored locally on your device. No internet required.
Universal & Accessible
Works with any refractometer available on the market. Only one upfront payment. Absolutely no subscriptions.
Plan — Design your recipe before brewing
Calculate all parameters of your recipe before touching the coffee. Enter your extraction targets (EY and TDS) along with your brew water, and Brewmetric automatically calculates the dose, beverage weight, ratio, and dissolved mass.
Measure — Analyze your actual extraction
After brewing your coffee, enter the data from your refractometer and Brewmetric calculates the Extraction Yield, dissolved mass, LRR, and provides a complete diagnosis. Instantly know if your coffee is over-extracted, under-extracted, or in the ideal zone.
Extraction Chart TDS vs EY
A professional chart inspired by the SCA Brewing Control Chart that visually shows where your coffee falls. Features customizable ideal zones, ratio lines, and two data points to compare your actual measurement against your plan.
Everything you need
Compare
| Feature | Brewmetric | The other app |
|---|---|---|
| Price | $9.99 | $39.99 |
| Compatibility | Any refractometer | Proprietary hardware only |
| Interface | Modern (SwiftUI, 2026) | Legacy (since 2010) |
| Formulas | The same (Lockhart 1957, SCA) | The same |
$9.99
One-time purchase. No subscriptions. No in-app purchases.
Includes all future updates.
App Store Pricing
This is how pricing works on the App Store: we
set a price in US Dollars, and then Apple
automatically defines the price in your currency.
We don't set the price in each country.
Please check your App Store to find out how
much Brewmetric costs in your country.
Why measure extraction?
You already know when your coffee tastes good. But do you know why — and how to repeat it every single time?
The science is simple. Hot water dissolves compounds from ground coffee. Too little extraction and it tastes sour and thin. Too much, and it's bitter and harsh. The sweet spot sits between 18% and 22%.
Sour, thin
Balanced, sweet
Bitter, harsh
The problem is, you can't measure this by taste. You need a coffee refractometer — a small optical instrument that reads your coffee's concentration in 3 seconds. Then you need Brewmetric to turn that number into actionable data: extraction yield, strength, ratio, and a clear diagnosis of what to adjust.
Measure TDS
Place a drop on the lens
Calculate extraction
Enter reading in Brewmetric
Dial in your recipe
Hit the 18–22% sweet spot
Any refractometer works. From the DiFluid R2 Extract (~$150) to the VST LAB Coffee III (~$700). Brewmetric is universal.