Perk: Coffee Brewing
The coffee app that shows its work. Tell it the coffee you bought, the gear you own and the water you have, and it gives you a brew plan you can follow — then tells you why every number is what it is.
- Tap any number. It tells you why. The reasoning sits beside the number, not behind a toggle.
- It labels what's measured, what's convention, and what's still open. Some numbers are marked “not yet” — Perk isn't guessing; it isn't there. That is the point, not an apology.
- Works with your grinder, your dripper, your water. The plan is built from the equipment you actually own.
- No account. No tracking. Your data stays on your phone unless you send it. Perk itself makes no network calls; purchases go through Apple's App Store. See the privacy policy — it is short, because there is nothing to hide in.
How Perk is built
Perk runs a brewing engine over a knowledge base of coffee research, and every number it shows you carries an evidence tier: measured in studies, estimated from evidence, known only as a direction, or not known yet. A number with no evidence behind it does not reach the screen. That rule is enforced by the app's own test suite, not by good intentions.
What that means at the counter: when Perk moves a number for you, it says which lever it moved, which of your own cups it learned from, and how well that is known. When it does not know, it says so and hands the question back to your palate.