Today I’m getting into the slightly nerdy stuff that can seriously save you coffee (and frustration): TDS and refractometers. If you’re not 100% happy with your home brews all the time—sometimes it’s great, sometimes it’s randomly bad and you have no clue why—you end up guessing and wasting half the bag just to find the sweet spot again. That’s exactly why I use TDS (Total Dissolved Solids): it tells you how concentrated your coffee is, and it gives you real data to help you brew consistently. In this video I show how I measure TDS using a refractometer (I tested a DiFluid unit that was sent to me). I walk through calibration (zeroing it with water), how to place the coffee on the lens, and why temperature matters—plus how this model offsets temperature changes and shows a graph while it stabilizes. I also measure multiple times because most refractometers can vary from reading to reading, and I trust the number once it keeps repeating. For pour over, I generally think it tastes best around 1.1% to 1.4% TDS. Over 1.5% can taste weirdly strong to me (though you should test and see what you like). My personal sweet spot is around 1.2%, and yes—0.1% is actually a huge difference when you’re dialing in.