Muscle Memory, Meet New Brew Method
At home, my morning coffee runs on autopilot. Kettle on, grinder whirring, V60 on the scale — 36g in, 600g of water out. I could do it half-asleep, and most mornings I do.
Then I spent a week out in Joshua Tree. Red rock, dry heat, zero cell signal at the cabin. Good coffee travels with me wherever I go, so I packed my hand grinder and an AeroPress — lighter, more portable, perfect for the trip.
First morning. Sun barely up, cool desert air coming through the screen door. I set the AeroPress on the counter and reached for the coffee bag. And then I just… stood there. I know how to brew an AeroPress. I’ve watched the videos, I’ve done it plenty of times. But the specific ratios? The water weight for a single cup? Gone. My fingers know my V60 recipe. They don’t know this one.
So there I am, squinting at my phone in a desert kitchen, searching for a brew ratio calculator while my kettle screams.
The Search That Started It All
There are plenty of decent options out there. Ratio charts, online calculators, Reddit threads from three years ago. They all work. But standing in that kitchen, what I really wanted was something that just lives on my phone — a beautifully designed app that’s a single tap away. One where I can store my go-to ratios and pull them up without thinking. Not whatever random tool Google decides to surface that morning.
I wanted the coffee equivalent of a calculator app. Always there, always instant, no friction.
More Than Just Travel
The Joshua Tree trip lit the fuse, but as I sat with the idea, I realized I reach for this kind of tool more often than I thought:
- Brewing for a crowd. Saturday morning, friends crashed at our place — suddenly I’m tripling my usual recipe and doing mental math that’s way too hard before coffee.
- Brewing a small cup. Just want to fill a travel mug, not my usual full pot. What’s the water for 18g?
- Scraping the bottom of the bag. There’s 10g of coffee left. Might as well brew it — but for how much water?
- Trying something new. Picked up a Chemex at a thrift store. Gorgeous thing, no idea where to start with ratios.
Every one of these is the same question: how much water for this much coffee? It takes five seconds to answer — if you have the right tool handy.
Simple Problem, Simple App
Coffee Calculator was built around one idea: enter your coffee weight, get your water weight. That’s the whole thing.
The design followed from there:
- One screen, one purpose. Open the app, type a number, see the result. No navigation, no setup, no onboarding flow.
- All the methods you actually use. V60, Chemex, AeroPress, French Press, Espresso, Cold Brew — each with sensible default ratios you can customize to match your taste.
- Flexible input. Start with coffee and calculate water, or start with water and calculate coffee. Some mornings you know how much coffee you have; other mornings you know how much you want in the cup.
- Your units, your way. Grams, ounces, milliliters — switch anytime and the math updates instantly.
Built to Stay Focused
Building this app has been a lesson in restraint. The temptation to keep adding is constant — timers, pour-over step guides, bean tracking, grind size charts. But every time a new feature idea comes up, I ask the same question: does this serve the core purpose?
The app should feel like a tool, not a platform. You pick it up, you use it, you put it down. The best session with Coffee Calculator lasts about five seconds. That’s a feature, not a limitation.
What’s Next
We’re building based on what the community asks for. If you have ideas for how we can make Coffee Calculator better — without losing what makes it simple — we’d love to hear them. You can submit feedback and feature requests from the Settings screen in the app, or visit our feedback board.
And if you haven’t tried it yet, download Coffee Calculator and see for yourself. Next time you’re standing in a kitchen — yours or someone else’s — wondering how much water you need, you’ll have the answer in a tap.