Support

Answers to the questions people ask most. Anything else: write to me, I read every message.

How do I back up my batches?

In the app, open More → Make a backup. Demijohn saves everything (batches, readings, additions, notes, reminders and settings) into one file and opens your phone’s share menu. Save it to Files, Google Drive, iCloud Drive, a computer or an email to yourself. I never see the file.

Make a fresh backup before you change or reset a phone.

How do I move to a new phone?

Install Demijohn on the new phone, open More → Restore a backup and pick the backup file. It replaces what is on that phone; you can undo right after. Then restore your purchase (next question) to get Pro back.

How do I get Pro back?

Open More → Restore purchases, or tap Restore purchases on the Pro screen. Use the same Google account or Apple ID you bought with. A purchase on Google Play does not carry over to the App Store, or the other way round.

How does the free trial work?

You can try Pro free for 7 days, once. It never turns into a payment by itself and there is nothing to cancel. When the 7 days are over, the Pro tools lock again until you buy Pro. Nothing you logged is deleted or hidden: every batch stays readable, editable and exportable.

Where do the formulas come from?

From published sources, and every result in the app shows its formula and source:

Gravity scales and temperature correction from the NBS sugar tables (Circular C440).
Potential alcohol and must sugar from OIV methods, 16.83 g/L per % ABV.
Sorbate by alcohol from Iowa State University Extension, sulfite limits from US and EU rules.
Honey composition from the National Honey Board.

The maths lives in a separate engine with hundreds of tests and 300 worked examples checked against an independent reference. The free calculators on this site use the same formulas.

SG, Brix, Oechsle, Blg, Babo or Baumé?

All of them. Pick your scale once; it is saved per batch and an update never resets it. Volumes in litres, US or UK gallons, temperatures in °C or °F, decimal comma or point.

Does it work with Campden tablets?

Yes. The sulfite calculator asks which form you use: powder (potassium metabisulfite), tablets or a stock solution. For tablets it also asks if they are potassium or sodium metabisulfite, because the dose differs.

Why does it ask for notifications?

Only for the reminders you set: the next nutrient step, racking, a check on the gravity. They are scheduled on your phone. If you say no, everything else still works.

How do I delete my data?

Uninstall the app. Your data exists only on your phone and in backup files you saved yourself, so that removes it. See the privacy policy.

Contact

Write to hello@mufatech.com. Tell me your phone model, the app version and what happened. For a number that looks wrong, add the inputs you used.

Email is the only support channel. I use your address only to reply.

Doses are estimates. Add in steps, test again, follow the product label. For personal use only.