The case for fresh.

Fresh coffee isn't the day it was roasted — it's the window where the bag tastes like what the roaster intended. That window exists because beans degas after roasting, then oxidize after peak. The chemistry and day-by-day schedule live in our science of coffee freshness; what it tastes like at each stage is in tasting the curve.

The short version: washed coffees peak around day seven, naturals around day eleven, with day nine as the rounded default this app is named for. Most home coffee is drunk long after that window closes — not unsafe, just flat.

The supply chain is brutal to coffee freshness. A typical bag of grocery-store specialty coffee was roasted four to six weeks before you bought it. Subscription services do better — Trade, Atlas, Mistobox ship within days of roast — but if you don't track it, you don't know.

And then there's storage. Pre-ground coffee stales five to ten times faster than whole bean. A clear glass jar on the counter lets light and oxygen do damage that an opaque vacuum canister would prevent. For the storage hierarchy, see how to store coffee to keep it fresh.

You log a bag in ten seconds. Roaster, roast date, how you store it. We compute the freshness curve with the actual variables — not just days since roast, but grind state, storage method, processing method. We send one notification on the day your beans hit peak. One more if they're sliding past it.

That's the entire app. It's deliberately small. Most coffee-tracking apps want you to log every brew, rate every cup, journal your thoughts. We don't. The thing that matters is timing, and timing is a one-touch problem.

Storage profiles in our model are heuristic — calibrated against published research and practitioner consensus, not yet empirically validated against thousands of brews. We're transparent about that in the architecture. As the dataset grows, we'll calibrate.

Peak-day estimates follow published degassing curves with process-specific adjustments — the full timing model is in the science of coffee freshness. Ground coffee gets a separate, steeper curve because surface area changes everything.