BrewmetricExtraction science in your pocket.
The professional TDS and coffee extraction calculator for iPhone. Pair with any refractometer to master your specialty coffee recipes with scientific precision following SCA standards. All in a single app, with no subscriptions or internet connection required.
Scientific Precision
Powered by the official SCA percolation and immersion formulas to ensure precise coffee calculations every single time.
Native & Offline
Built exclusively for iOS. Your recipes and measurements are stored securely on your device, ready to use even without an internet connection.
Universal & Subscription-Free
Works flawlessly with any refractometer. One single upfront payment unlocks the entire app forever. Absolutely no subscriptions.
Plan — Design your recipe before brewing
Calculate all parameters of your recipe before touching the coffee. Enter your extraction targets (Extraction Yield 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 your Extraction, the true amount of dissolved mass, and provides a complete diagnosis. Instantly know if your coffee is over-extracted, under-extracted, or in the ideal zone.
Interactive Extraction Chart
A professional tool inspired by the SCA Brewing Control Chart that visually shows where your coffee falls. It features customizable ideal zones, ratio lines, and dual data points to instantly compare your actual cup 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 |
| Updates | Regular updates & new features | Abandoned years ago |
$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. Coffee is a fruit, and we extract it to reveal its natural sweetness. Hot water dissolves compounds from ground coffee at different rates. Too little extraction and it tastes sour and thin. Too much, and it's bitter and harsh. The sweet spot for Extraction Yield sits between 18% and 22%, whether you brew espresso or filter.
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 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 (~$199) to the VST LAB Coffee III (~$700). Brewmetric is universal.