Sign up for newsletter

What size garden do you have? (approximately)

The Age Old Art of Preserving


Notes prepared by Maria Ciavarella of My Green Garden, February 2024


Please follow preserving recipes carefully as poorly preserved produce may lead to fatal results. What follows are just tips and techniques for many preserving methods and not strict recipes.

Introduction – Safe Preserving Basics

Preserving makes the most of seasonal fresh produce to enjoy later. Even if you don’t grow your own, visiting farmers’ markets and good greengrocers will give you an idea of what is in abundance. That makes it the best time to preserve them too. This way you have complete control of what is going in your preserves. Preserving the abundance is an important element of the slow-food movement, and sometimes a necessary skill if you are a keen gardener, or just a
keen foodie.

You might have time-honoured recipes handed down from generation to generation that you would like to try but if not, don’t
fret, as there are many books and web-links available with recipes galore for main ingredients. Many can be completed in an evening after work, or even started on one night and then continued the next, so even the time-poor can enjoy this culinary art. Who knows? You might even be inspired to show your wares at your local agricultural shows!

This booklet outlines different techniques for preserving, such as bottling, making jams, dehydrating, making chutneys and pickles. By no means exhaustive it offers a simple entry into the world of the bottlers and picklers. Enjoy the journey!

Preserving slows down food spoilants by altering conditions so that they don’t thrive. This can be done by removing moisture, acidifying the ingredients, excluding oxygen, using temperature and alcohol.

First thing’s first

Sterilising jars and lids

This is necessary to avoid bacteria and other food spoilants contaminating your preserves. After all, why take the effort of making great preserves if they only spoil because the containers aren’t sterile? Luckily, it’s not difficult to do.

Glass jars that come with metal lids can be re-used time and time again, but you will need to replace the lids if they are showing any signs of wear.

First, wash jars and metal lids thoroughly in hot soapy water and rinse well.

To sterilise glass jars

SEVERAL methods can be used for sterilizing glass jars or bottles. Choose which suits you best.

1. Put the clean jars in a slow oven (from 110C – 130C) for at least 20 minutes. If filling with hot preserves, leave the jars in the oven until they are needed.

2. Put the jars and lids through a hot rinse cycle in the dishwasher and dry hot in the dishwasher.

3. Place the washed jars and lids in a deep saucepan and cover with water. You may want to line the base and sides with a tea-towel to stop the jars rattling. Bring to the boil and boil rapidly for 10 minutes. Lift the jars out carefully and drain upside down on a clean tea towel. Allow to dry.

4. Microwave sterilising units (as used to sterilise baby bottles) are a fast alternative to sterilising limited numbers of jars at a time.

5. In the microwave you can also sterilise by half filling the clean jars with water, heating them in the microwave for enough time to see the water boiling for at least 30 seconds, and then tipping the hot water out before filling with the preserves. Be careful with the hot water!

6. Use Milton sterilising tablets in a large plastic tub. These are usually available in the baby aisle of large supermarkets.

To sterilise metal lids

First of all, ensure that the lids are not showing signs of wear if you are re-using old lids. If the paint is worn, there is the potential for the lids to corrode when storing preserves, especially pickles. It’s always safest to buy new lids to use.

To sterilise lids, place the lids in a saucepan with cold water and bring them to the boil for about 10 minutes. Remove and drain on a clean tea-towel while waiting to use them.

Heat preserving

Heat preserving or heat processing is a great way to have in the pantry fruits that you may have grown in abundance. The unblemished fruits are packed into clean jars and then filled with water or a sugar syrup solution. It is best to use under-ripe fruit as they will keep their shape during the heat processing time.

Heat processing will vacuum-seal the jars to exclude oxygen, which slows down or prevents food spoilants from thriving.

This process is also known as bottling, canning or vacuum-sealing.

Bottling can be done using the Fowlers Vacola preserving unit with its equipment. If you don’t have a Fowlers Vacola unit, you can use clean jars and new metal lids in a large deep pot (eg stock pot) on a stove top hot water bath.


To do this:

  1. Prevent the jars coming into direct contact with the bottom and sides of the pot by placing a metal rack or trivet, or a tea towel on the bottom; and wrap each jar in teatowels or put cardboard between the jars so they are packed in firmly against each other.
  2. Pour in enough water to cover the jars by at least 2.5cm. If the preserves were hot in the jars, use warm water to fill the pot. If they were cold, use cold water to fill.
  3. Turn on the heat and slowly bring the water to the boil. This should take about ½ hour and at no time should boil hard. Once at a slow boil, lower the heat so that a gentle simmer is maintained for the required time. Remove from heat.
  4. If the contents were cooked originally before heat preserving, you can allow them to cool in the water as the water cools down. Otherwise, use tongs to carefully remove the jars, place on a rack or towel-covered surface and leave to cool completely before labelling and storing.

For step-by-step photos on the bottling process, visit and search “bottling”.

Chutneys, relishes and sauces

If you are new to preserving, these are great ones to start with. Good recipes will have the correct combination or amounts of the ingredients necessary to safely preserve the product. Most are simply a matter of chopping your fresh ingredients and add them to a large, heavy-based cooking pan along with the preserving ingredients, usually containing sugar and vinegar. They help preserve by creating conditions that prevent food spoilants taking hold. Sealing jars while hot also helps create a vacuum
seal, which stops air from entering. Of course, once opened, these preserves should be stored in the

Most recipes are a one-step process, so look for a recipe that uses up what you are growing in your garden or is in seasonal abundance

Drying or dehydration

Drying fruits and vegetables, or dehydrating them, is another tasty way to concentrate the natural flavour in food and preserve it for long-keeping. Traditionally, drying foods would have been done using the sun, though long hot days free of humidity are needed, conditions that can be a bit haphazard usually. Instead, for drying, most would now use a dehydrator, a unit which runs on power. It consists of several stacked trays with a lid and gentle warm air is blown through. Drying times can vary according to the original water content of the produce and how thinly it is sliced but sometimes can be as short as a few hours. As long as the dried food can be kept dry it will last for a long time.

Jams, conserves and marmalades

When making jams, conserves or marmalades, there is a magic that happens when certain elements come together. This magic is what makes the mix gel or set to become more than fruit syrup.

= JAM (or Conserve or Marmalade)

Many fruits can be made into jams but certain conditions, such as the amount of acid and pectin, must be met in order to get the jam to gel. Pectin is a substance found in most fruits to an extent that, when at the right temperature and in the presence of acid, reacts with sugar to cause the mixture to set. Slightly under-ripe fruit will contain more pectin that over-ripe fruit, so it’s a good idea to start making jam with fruit early in the season rather than at the end.

Some fruits naturally meet the necessary acid and pectin amounts, but otherwise these ingredients can be added by including lemon juice (contains both pectin and acid); reserving the pips or stones and cooking these as well for the pectin; or adding a commercial setting agent, such as Jamsetta. Remove any bruises or damaged parts from the fruit before using.

When adding sugar, you may find the amount of sugar required quite confronting! Keep in mind that the sugar is not just there to create the set of the jam, but acts as the preserving agent in the jam. The sugar concentration creates conditions that discourage mould and bacteria to flourish. The general rule is to add ¾ to 1 cup of sugar to every cup of fruit mix. If you use the lower amount, you will find that the jam will have a less firm consistency, but more easily spreadable. It shouldn’t however, be runny like a syrup.

Acid & Pectin balance

Fruits with good balance of acid and pectin: grapes, crab apples, quinces, grapefruit, lemons, limes, sour apples, sour oranges, sour plums.

High in pectin but low in acid: sweet apples, sweet quinces. You will need to add 2 tablespoons of lemon juice to every kilo of fruit to increase the acid content.

Low in pectin but high in acid: apricots, pineapples, rhubarb, sour peaches. Add 2 tablespoons of lemon juice to every kilo of fruit to increase the pectin content and add the lemon pips in a muslin pouch to the cooking of the jam (remove once finished!).

Fruits low in pectin and low in acid: Pears, melons, sweet peaches, some berries and cherries. These will need the addition of other fruits or juices or Jamsetta to make a firm setting jam.

Use wide heavy based pans for your jam making to prevent scorching and for faster evaporation, but don’t overfill because the jam will boil over making a very sticky mess!

Testing for setting point in jams

Keep a small stack of saucers in the freezer. You do this so as to get the hot jam to cool quickly to room temperature to show you whether it has set or is still very runny. Take a teaspoon of the jam while cooking and place it on the cold saucer. Put it back in the freezer for one minute and then take it out. (In the meantime, turn off the cooking so that it doesn’t continue while you’re waiting for your test). Run your finger through the jam and see if it stays apart or oozes back to the centre. If it stays
apart the jam is set. If not, continue cooking and then check again soon after.

White background overlay

If you discover that the jam has set hard once cold, all is not lost! Empty it back into a saucepan, add a little water and then re-heat while mixing. Place back into a clean jar. OR, if it still hasn’t set enough once cold, heat again for longer, testing as before; or add Jamsetta as pectin while re-heating.

If you are satisfied with the set, leave the jam for a few minutes before bottling. This helps distribute the fruit in the jam so that it doesn’t all rise to the top.

Hot jam goes into hot sterilised jars and then seal immediately. Once sealed, tip the jars upside down for several minutes as this aids the vacuum sealing process and also helps sterilise the lids.

To increase the shelf-life of jams, you may also want to heat process (see page 3) them to help them keep (unopened) for up to 2 years. Otherwise, 6-12 months is the maximum recommended storing time of unopened jams, especially if you lowered the amount of sugar in the jam.

Best results come from making small batches at a time. Do not use more than 2 kg at a time of combined fruit and sugar. The shorter cooking time will result in better texture, appearance and importantly, flavour. Wide open saucepans are also better for faster cooking. Of course, when bottling jams, small jars are better to use than large ones if available. This way, you don’t have a large jar waiting to be consumed once opened as jams can start to spoil once exposed to air, even
when refrigerated.

Pickling using vinegars

Many vegetables can be preserved by pickling in vinegar, where the acid content of the liquid prevents spoiling of the food. However, note that you need a minimum vinegar content in the pickling liquid in order to prevent botulism in low acid vegetables.
There are usually two stages to the pickling process.

Stage 1: Vegetables are salted to draw out excess moisture. This is either in a brine (salt in water) solution or dry salted. This is kept up to overnight in a cool place and then the resulting liquid drained off and the vegetables rinsed the next day. (Some low water vegies, such as beetroot, radishes and cauliflower can skip this pre-salting step).

Stage 2: The vinegar is boiled briefly with flavourings, such as chilli, bay leaves, peppercorns and mustard seeds. The vegetables are then covered with the (strained) vinegar in the sterilised jars. For crunchy pickles, you will need to allow the vinegar to cool before pouring. For softer pickles, use the vinegar still hot.

Sometimes recipes will have a weaker acid solution but make up for that by using a vinegar/brine solution.

Other recipes, particularly those with a Mediterranean influence, use both brine and vinegar to prepare the vegies. These are then squeezed out of them and the pickled vegies are stored under olive oil. This means that excess moisture has been removed, the vegies have the required acidity AND air is excluded by storing under oil.

Green Tomato Mustard Pickle is a firm favourite and always features in ‘Preserving with Tomatoes’ workshops held by My Green Garden in summer.


Although each step is not difficult, this is a pickle that is made over 3 days. The result is a firm textured pickled vegetable that is kept under olive oil. These are used in antipasto platters or with crusty bread, all the better for mopping up the deliciously flavoured olive oil that takes on the taste of the pickle. You can use zucchini, eggplant, green capsicum and green (unripe) tomatoes with this technique, or a mix of any of them.

Step 1: Drawing out the water in the vegetables
Slice the chosen vegetable into 3-5mm slices. Layer these in a ceramic or glass bowl, sprinkling each layer generously
with cooking salt. Place a heavy weight over them and leave overnight.


Step 2: Rinsing and then pickling with vinegar
Rinse the vegetables very well the next day of all of the salty water that has accumulated. Drain and then place back in the bowl, this time adding a generous amount of white wine vinegar. It does not have to cover the vegies, but you do need to weight them again. Leave again overnight.

Step 3: Drying and dressing
Drain the vegies of the vinegar and then squeeze them very well by hand. Return them to the bowl and dress generously with olive oil. You can also add dried oregano, peppercorns, chilli or other dried herbs to taste.

Pack the dressed pickled vegies into sterile jars and fill the jar with more olive oil, releasing any air bubbles. Seal and keep for a month before eating to let the flavours develop. Buon appetito!

Step-by-step instructions can be found at

Curing and pickling olives

Olives straight off a tree are very bitter and inedible. The bitter element in the olive is water soluble so regular water changing
can cure olives. It is also removed by salting. Curing olives refers to the process of removing the bitterness to make them
edible and then pickling enhances the flavour and preserves the olives for long-keeping. There are so many variations in
these processes and these also vary depending on the ripeness of the olives. All olives start green and then gradually turn to black when they are considered ripe.

In the easiest of these processes, the curing and pickling is done at the same time.

White background overlay

The curing of olives to an edible state is the ultimate slow food technique. You can speed it up by the amount of effort you put in before placing in jars, such as slitting or splitting the olives, changing water and salting.

A simple method for green olives

Simply jar the washed green olives and then fill the jar with a cool 10% brine solution (100g salt dissolved in 1 litre of boiled water). Place a slice of lemon on top to acidify the solution and then pour over a 5mm layer of olive oil to help exclude oxygen. Place a lid on and then store away from sunlight. When the olives go from bright green to an ‘olive’ colour, they will be ready. This may take up to a year or even two, depending on the size, the ripeness and the variety of the olives. Once cured, rinse off the brine and dress with garlic, herbs and oil to taste.

For more techniques on the preserving of olives or other produce, visit
or enrol in one of the many preserving workshops run by My Green Garden.
Details are on the website.