Privacy policy

Last updated: 25 October 2026

Short version: Demijohn collects no data. Everything you enter stays on your phone.

What I collect

Nothing. Demijohn has no account, no analytics, no advertising, no crash reporting and no tracking of any kind. It contains no third-party code that collects data.

What stays on your phone

Your batches, readings, additions, notes, reminders and settings are saved in the app’s private storage on your phone. I can’t see them and I have no copy.

Photos you attach to a batch are picked with the system photo picker; the app keeps its own copy and asks for no access to your photo library. The home-screen widget reads the same data on your phone.

Backups and exports

A backup is one file. A batch sheet is a PDF, a CSV export a spreadsheet file. Your phone’s share menu or file picker sends them where you choose: Files, Google Drive, iCloud Drive, a computer, an email to yourself. Those services handle the file under their own privacy policies. I never receive it.

Phone backups

If your phone’s own backup is turned on (Google or iCloud), it may include Demijohn’s data like most apps’ data. Google and Apple handle those backups under their own privacy policies.

Network

Demijohn makes no network requests of its own. The only exception is purchases: buying or restoring Pro is handled by Google Play or the Apple App Store under their privacy policies. I don’t receive your payment details. The app only gets the purchase status from the store and saves it on your phone.

Permissions

The only permission Demijohn asks for is notifications, for the reminders you set. They are scheduled on your phone; no push service is involved. No camera, location, contacts, microphone or Bluetooth.

Email

If you email me, I receive your email address and your message. I use them only to answer you, I don’t share them and I don’t add you to any list. Ask at any time and I delete them.

This website

This site sets no cookies, has no analytics and loads nothing from other servers. The calculators run in your browser; what you type is not sent or stored, and it is gone when you close the page. The site is hosted on GitHub Pages; GitHub may log technical data such as IP addresses for security, as its own privacy statement describes.

Age

Demijohn is for adults who make wine, mead or cider at home for their own use. It is not directed at children, and it collects no data from anyone.

Your rights

I hold no app data about you, so there is nothing to access, correct or delete on my side. To delete everything in the app, uninstall it. For emails you sent me, write and I delete them. You can also complain to your local data protection authority.

Changes and contact

If this policy changes, I update this page and the date above. Contact: hello@mufatech.com