Difluid R2 Extract TDS Meter

Know your TDS!

There's a certain satisfaction in knowing your coffee is doing exactly what you think it is. Not guessing. Not approximating. Knowing. The Difluid R2 Extract is built for that kind of certainty.

What the R2 Does

The R2 Extract measures total dissolved solids (TDS) in your brew — quickly, accurately, and without the fuss of traditional refractometers. Pair it with CoffeeOS and it goes further: logging your brews automatically, calculating extraction yield in real time, and mapping results directly onto the Brew Control Chart. The data you've always wanted, finally in a format that actually helps you act on it.

Why the R2 is Different

Most refractometers are delicate instruments built around a small sensor vulnerable to ambient light — requiring a lid, careful handling, and a fair amount of patience. The R2 Extract takes a different approach. Its larger CMOS sensor dramatically reduces the influence of external light, making it more accurate, more durable, and lid-free by design. It connects via Bluetooth and lives inside your workflow, not outside of it.

Built for Every Brew - from pourover to expresso

With a TDS range of 0–30%, the R2 Extract handles everything from a delicate filter to a concentrated espresso shot. For espresso, a quick filter before measuring keeps oils from interfering — though even unfiltered, the oversized sensor produces results that are notably more accurate than what you'd expect from conventional tools.

Calibration is equally straightforward: use distilled water for absolute comparability across setups, or your actual brew water for the most precise extraction calculations.

Who is the R2 For

Whether you're dialing in at a café, developing a new roast, or simply trying to brew the same great cup twice — the R2 Extract gives you the feedback loop to make it happen. Repeatable results aren't an accident. They're a practice.

What kind of water should I use to calibrate?

For calibrating your R2 TDS meter, use distilled or RO water to set the calibration to zero.

For understanding your brew TDS, also measure your water TDS to compare. To dial in your water, we recommend using our Apax Lab Mineral Concentrates.