When the screen locks
The timer anchors to an epoch and recomputes on return. It also attempts a screen Wake Lock after Start; denial never blocks the recipe.
Absolute time, not interval counting
Coffee brew timer
CupTune recalculates elapsed time after backgrounding or reload, so a delayed callback does not silently shift the recipe.
Step 1
Ready to start
00:00
Next target appears here.
Timer ready. Sound, speech and vibration are off.
Reload recovery
An in-progress session is stored locally with its recipe id and elapsed anchor. Resume or discard it from this device only.
Questions before the next brew
Does CupTune upload my brew journal?
No. Recipes, timer state, bean details, measurements and notes stay in this browser unless you explicitly export a file.
Does CupTune decide whether coffee tastes correct?
No. It keeps measurements comparable and suggests one controlled change; taste remains your preference.
Can I use the tools offline?
After one successful load, the application shell and authored routes are cached. Advertising, analytics and email links can be unavailable without blocking the tools.
Why does extraction yield require TDS?
Extraction yield needs a measured dissolved-solids value. CupTune will not invent one from roast, colour, method or taste.