Jarwise: Canning Timer & Log

A canning timer and log that shows only the USDA's tested process times, adjusted for your altitude, and walks you through the canner step by step.

Coming to Google PlayFinished and waiting for its Google Play listing.

Free
Works offline
No account
No subscription

App languages: English

Jarwise is a canning timer and canning log built on the USDA Complete Guide to Home Canning. Pick a food, your canner, the pack and the jar size, and it shows the guide's tested process time and pressure for your altitude, with the page it comes from.

Then it walks you through the canner, step by step, and keeps a log of every batch and every sealed jar on your shelf, oldest first.

Screenshots

Why we built it

Recipe apps that mix tested and untested times. Every time and pressure in Jarwise is copied from the USDA guide's tables, with its page. If the guide has no tested process for a combination, Jarwise says so and shows no time.
Altitude tables you have to read yourself. Set your altitude once, in feet or metres, and every time and pressure is already adjusted. The full table is one tap away, with your band highlighted.
A kitchen timer that knows nothing about pressure canning. The canner timer covers venting, coming up to pressure, processing, letting the pressure fall, the wait before opening and cooling, and restarts the full time if the boil or pressure drops.
Forgetting what is on the shelf and how old it is. A log of every batch with jars that didn't seal, and a pantry of sealed jars with use-within-a-year dates.

Features

Tested times only

98 foods from the USDA guide: fruit, tomatoes, vegetables, meat, poultry and seafood
Every time and pressure is copied from the guide's tables, with the page it comes from
Water bath, weighted-gauge and dial-gauge pressure canners, each with its own pressures
If the guide has no tested process for a combination, Jarwise says so and shows no time. It never guesses, never stretches a time to a bigger jar and never lets you edit a process time
Low-acid foods (vegetables, meat, poultry, seafood) only get pressure canner processes
Headspace, hot or raw pack, and the acid to add to tomatoes, straight from the guide

Your altitude, set once

Enter your altitude in feet or metres once; every time and pressure adjusts to your band
The full table for each food, with your band highlighted
Weighted or dial gauge: tell Jarwise what you own and it shows that first

A canner timer that knows the steps

Venting, bringing up to pressure, processing, letting the pressure fall, the wait before opening, and cooling, each explained as you go
If the boil stops or the pressure drops, restart the full process time with one tap, as the guide says
The screen stays on while the timer runs, with alerts at the end of each step
A reminder to check the seals 12 hours later

Log and pantry

Every batch: food, date, jars, the process used, jars that didn't seal, notes
A pantry of sealed jars, oldest first, with "use within a year" dates
Use a jar with one tap; export your log to CSV
Supplies checklist for canning day

Safety essentials in plain words

Why low-acid foods need a pressure canner, why tested times matter, altitude, headspace, seals, storage and signs of spoilage, each with its page in the USDA guide
A link to open the guide itself for the full directions and recipes

Private and offline

No account: your log stays on your phone. Back up to one file and restore on a new phone
Free with ads. An optional one-time purchase removes them; no subscription, nothing locked

How it works

The guide's tables were transcribed by hand, row by row, and a script turns the transcription into the app's data, adding each food's page and headspace from the guide.

A second, separately written checker compares every data row back against the text of the guide's PDFs: the times, the pressures, the altitude bands, the jar sizes and the pack styles, and that no printed row was left out. It was itself tested against deliberate errors.

The app only looks up a row; it never computes a time. Metres are converted with 1 ft = 0.3048 m and rounded up, so a converted altitude can only land in the safer band.

Automated tests pin the safety rules: no low-acid food has a water-bath process, low-acid pressures are only the guide's 10 or 15 psi (weighted) and 11 to 14 psi (dial), and times never get shorter as altitude rises.

Honest limits

Jarwise is a companion to the USDA guide, not a replacement: follow the guide's directions exactly. For salsas, sauces, pie fillings and other mixtures, the time only holds with the guide's own recipe, and Jarwise links to its page.
Pickles, fermented foods, jams and jellies (Guides 6 and 7) are not included yet.
The guide's dial-gauge tables stop at 8,000 ft, so Jarwise gives no dial-gauge pressure above that altitude.
Step alerts can arrive many minutes late, because Android delays them to save battery; the timer screen, which stays on while it runs, is the reference.

Questions

Where do the canning times in Jarwise come from?

From the USDA Complete Guide to Home Canning, 2015 revision, published online by the National Center for Home Food Preservation. Each time shows the guide page it comes from.

How does altitude change canning times?

Water boils at a lower temperature higher up, so water-bath times get longer and pressure canners need more pressure. Jarwise picks the guide's altitude band for your altitude.

Can I water-bath can green beans or meat?

No. The guide only gives pressure canner processes for low-acid foods such as vegetables, meat, poultry and seafood, because a boiling-water canner can't destroy botulinum spores in them. Jarwise shows no water-bath time for them.

What if my food or jar size isn't listed?

Then the guide has no tested process for it, and Jarwise says so instead of guessing. It never stretches a time to a bigger jar.

Weighted gauge or dial gauge: what's the difference?

A weighted gauge holds 10 or 15 psi; a dial gauge shows the pressure and has its own table by altitude. Tell Jarwise which you own and it shows that one first.

What happens if the pressure drops while processing?

As the guide says, bring the canner back up and time the whole process again from the beginning. The Jarwise timer has a button for exactly that.

Does Jarwise need an account or internet?

No. Everything works offline and your log stays on your phone. You can back it up to a file and restore it on a new phone.

Guides

Pressure canning times for vegetables: the USDA chart

How long to pressure can green beans, corn, potatoes, carrots and every vegetable in the USDA guide, with headspace and the pressure for your altitude.

How long to water bath tomatoes, tomato juice and sauce

Water-bath times for whole, crushed and juiced tomatoes and tomato sauce by altitude, the acid every jar needs, and the pressure options, from the USDA guide.

Canning altitude adjustment chart: water bath and pressure

How altitude changes home canning: longer water-bath times by altitude band, and higher pressure for weighted and dial gauges, from the USDA guide.

Water bath vs pressure canning: which foods need which

Why vegetables, meat and seafood need a pressure canner, which fruit and tomato products can go in a water bath, and how the methods differ (USDA guide).

Pressure canning times for meat, chicken and broth

How long to pressure can meat chunks, ground meat, chicken with or without bones and meat stock, with headspace and the pressure for your altitude (USDA).

Headspace for canning: a chart by food

How much headspace to leave when canning tomatoes, sauce, fruit, juice, vegetables and meat, from 1/4 to 1 1/4 inches, and why it matters (USDA guide).

Private and offline

Runs entirely on your phone and works offline. No account, no sign-up, and your data stays on your device. The app shows ads through Google AdMob; see the privacy policy. Privacy policy.

Free. An optional one-time purchase removes the ads; nothing is locked and there is no subscription.