Coffee Freshness Calculator
Fresh coffee is not always better coffee. Some beans drink best after a few days; dense light and Nordic roasts can need several weeks to open up. Wait too long and even an expensive bag turns flat. Enter your bag and your pace to see whether to brew now, wait, freeze part of it, or buy less next time.
These estimates come from heuristic roast-style priors, not lab measurements. Treat the result as a starting point and let taste confirm it. See the model.
How to read the result
The model treats a bag as two competing processes. Resting raises drinkability after roast as carbon dioxide escapes and extraction evens out. Staling lowers it as aromatics fade. Their product is the hump-shaped curve above: too young, then a good window, then a peak, then decline.
Because you drink a bag over time, the calculator scores the average quality across the days you will own it, not just today. That is why a slightly-too-fresh bag that will peak in your hands is not marked down, and why a large bag at a slow pace gets a freeze or buy-less nudge.
These are heuristic priors informed by the Specialty Coffee Association's staling review and our own guide to resting coffee, not lab measurements for your specific bean. Use the result as a starting point and let taste confirm it. To pick better beans in the first place, see how to buy good coffee beans.
Want the math? The model and its assumptions are written up in MODEL.md, and the engine is open source under the MIT license.