How to Make Passata and Bottle It Safely
Updated October 2026
Every jar of tomatoes needs added acid, a tested boiling time and jars no bigger than 946 ml. Here is the method, in Australian measures.
Sieve your cooked tomatoes into passata, put measured acid in each jar, fill it hot and boil the jars for 35 to 40 minutes. That is the whole job. The acid is the part people skip, and it is the part that keeps botulism out of the jar: the Food Safety Information Council says tomatoes must have citric acid added before bottling. The times below are the tested USDA times for sieved tomato juice and sauce, the closest tested process to passata.
Passata yield and acid calculator
Enter the weight of ripe tomatoes. The calculator gives a rough yield, the acid for each jar and the boiling time for your altitude.
Measure the acid in millilitres. USDA's amounts use a 15 ml tablespoon. An Australian tablespoon is 20 ml, so we give millilitres and teaspoons instead.
- Jars up to 473 ml (a US pint, such as a 250 ml jar): 15 ml bottled lemon juice or 1/4 teaspoon citric acid.
- Jars from 474 to 946 ml (500 ml, 700 ml and 750 ml jars): 30 ml bottled lemon juice or 1/2 teaspoon citric acid.
- 1 litre jars and bigger: no tested time exists. Use smaller jars or freeze.
Bottled lemon juice, not fresh: its acidity is standardised. Citric acid is sold in the baking aisle. Salt is for flavour and does nothing for safety.
The method
- Hot break. Quarter about 500 g of washed, cored tomatoes into a big pot and bring them straight to the boil, crushing as you go. Keep adding quartered tomatoes a few at a time so the pot never stops boiling. Simmer 5 minutes once they are all in. Fast heating stops the passata separating into a watery layer.
- Mill. Push the hot tomatoes through a food mill or a fine sieve to take out skins and seeds.
- Acid and salt. Put the measured acid in each clean jar. Add salt if you like it, up to 1 teaspoon per litre of passata.
- Back to the boil. Reheat the passata to boiling and fill the jars hot.
- Headspace. Leave 1.25 cm at the top for plain passata, or 6 mm if you cooked it down to a thick sauce. Run a clean plastic spatula down the inside to free bubbles, then wipe the rims.
- Lids. Two-piece Mason lids go on fingertip tight. Fowlers jars take a new rubber ring, lid and clip.
Boiling the jars
Stand the jars on a rack in a deep pot, cover them with water by at least 5 cm (USDA asks for 5 cm when the time runs over 30 minutes), put the lid on and bring it to a full rolling boil. Start the clock only at the boil. If it drops off the boil, bring it back and start the time again from zero.
| Altitude | Jars up to 473 ml | Jars 474 to 946 ml |
|---|---|---|
| 0 to 300 m | 35 minutes | 40 minutes |
| 301 to 900 m | 40 minutes | 45 minutes |
| 901 to 1,800 m | 45 minutes | 50 minutes |
Most coastal cities sit in the first row. Canberra, Toowoomba and Ballarat are in the second, and the higher parts of the Blue Mountains and the New England Tablelands reach the third. When the time is up, turn the heat off, take the lid off and wait 5 minutes before lifting the jars onto a towel, 2.5 cm apart. Leave them 12 to 24 hours.
Using a Fowlers Vacola unit
A Fowlers unit can do this job only if it holds the water at a full rolling boil with 5 cm of water over the jar tops for the whole time in the table. Many Fowlers instructions use a slower heat-up and a simmer; those are the maker's directions and were not tested against these times. Tall Fowlers jars often leave too little water above them, and the big sizes hold more than 946 ml, so check the capacity in millilitres before you choose a jar.
When is passata season?
It depends on where you garden. Melbourne, Adelaide, Canberra and Hobart plant out in spring and pick the glut from late summer into autumn. South East Queensland has two sowings, so a crop comes in early summer and another in winter. In Darwin, tomatoes are a dry season crop picked in the cooler months. Our tomato growing guide has the window for each region.
Storing and checking the jars
Take the bands or clips off once the jars are sealed, wipe them, label them and keep them in a dark cupboard. USDA advises 10 to 21°C and never above 35°C, so not the garage, and use them within a year. Once opened, keep the jar covered in the fridge and use it within a few days.
If a lid has not sealed after 24 hours, put on a new lid and process it again for the full time within those 24 hours, or refrigerate it and use it within a week. Throw out any jar with a bulging lid, spurting or fizzing liquid, an off smell or mould, without tasting it.
A clear watery layer under the pulp is harmless and comes from slow heating; shake the jar before you use it.
Sources we checked (October 2026): Food Safety Information Council, Home bottling and canning; Food Standards Australia New Zealand, Clostridium botulinum; USDA Complete Guide to Home Canning (2015) through the National Center for Home Food Preservation: Tomato Juice, Standard Tomato Sauce, Tomato acidification directions, Using Boiling Water Canners, Storing Home Canned Foods.
Common questions
How much citric acid goes in a 500 ml jar of passata?
Half a teaspoon, or 30 ml of bottled lemon juice. A 500 ml jar is bigger than a US pint, so it takes the quart amount and the quart time of 40 minutes at low altitude.
Can I use fresh lemon juice?
No. Fresh lemons vary in acidity. Use bottled lemon juice or citric acid, which are consistent.
Can I bottle passata in 1 litre jars?
Not safely. Tested times stop at 946 ml, so a 1 litre jar has none. Use 500 ml or 700 ml jars, or freeze the passata in containers.
Do I still need acid if I use a Fowlers unit?
Yes. Acid goes in every jar of tomatoes whatever you process them in. The Food Safety Information Council says tomatoes must have citric acid added before bottling.
My jar did not seal. Is it wasted?
No. Within 24 hours you can fit a new lid and process it again for the full time, or put it in the fridge and use it within a week.