HomeResourcesResourcesFoodPreserving Basics

Preserving Basics

These notes discuss many of the techniques necessary to get your preserving kitchen into top gear. Find hints on bottling, drying and dressing, sterilising, and balancing your pectins, amongst many others.

© Maria Ciavarella, My Green Garden


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 and that it is the best time to actually preserve them too. This way you have complete control of what is going in your preserves – and they will all be whole foods. 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 available with recipes galore for many ingredients. Many recipes 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 the Royal Melbourne Show!

These notes discuss many of the techniques necessary to get your preserving kitchen into top gear. Find hints on bottling, drying and dressing, sterilising, and balancing your pectins, amongst many others.


This booklet outlines a series of different techniques for preserving, which is by no means exhaustive.

WARNING Please follow recipes carefully as poorly preserved produce may lead to fatal botulism. The following are just tips and techniques and not recipes.

Heat Preserving

Heat preserving is a great way to have in the pantry fruits that you may have grown in abundance. Heat processing will vacuum-seal the jars which excludes oxygen, to prevent spoilants from thriving. This is also known as bottling or canning. Bottling can be done using the Fowlers Vacola preserving unit with its

If you don’t have a Fowlers Vacola unit, you can use clean jars and clean 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 bottomand 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.

Preserving Techniques

Italian Pickles sott’olio

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 thicknesses. Layer these in a ceramic or glass bowl, sprinkling each layer generously with 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 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 veggies, but you do need to weight them again. Leave overnight. Step 3: Drying and dressing
Drain the veggies 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, chopped garlic, chilli or other dried herbs to taste. Pack the dressed pickled veggies 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!

Preserving techniques


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 in the sunshine, though long hot days free of humidity are needed, conditions that can be a bit haphazard usually. Instead, most preserving addicts would now use a Dehydrating Unit, which runs on electricity. It consists of several trays all stacked together with a lid and gentle warm air is blown through. Drying times can vary according to the original water content of the produce but sometimes can be as little as overnight.

Curing and pickling olives

Olives straight off a tree are very bitter and inedible. Curing olives refers to the process of taking the bitterness away and then pickling enhances the flavour. In the easiest process, the curing and pickling is done at the same time.

Curing olives to an edible state is the ultimate slow food technique. You can speed it up by the amount of effort you are prepared to do at the start of the process.

Simply jar the 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, lid on and then store away from sunlight. When the olives turn an ‘olive’ colour, they will be ready. This may take up to a year, depending on the size and the variety of the olives. Rinse and dress with herbs etc to taste. (For more techniques, visit www.mygreengarden.com.au)

First things first

Sterilising jars and lids

This is necessary if the contents of the jar are not going to be heat processed. Re-use old glass jars with metal lids, but replace the lids if they are showing wear.

First wash jars and metal lids thoroughly in hot soapy water and rinse well. Several methods can be used for sterilizing the jars or bottles.

  1. Put the clean jars in a slow oven (from 110oC – 130oC) for at least 10 minutes. Boil the lids in a saucepan for a few minutes. If filling with hot preserves, leave the jars in the oven until they are needed. If you are putting cold ingredients in the jars, allow them to cool before filling. Rule: hot preserves in hot sterile jars, cold preserves in cold sterile jars.
  2. Put the jars and lids through a hot rinse cycle in the dishwasher and then use as above (hot to hot rule).
  3. Place the washed jars and lids in a deep pan and cover with water. You may want to line the base and sides with a tea-towel to stop them rattling. Bring to the boil and boil rapidly for 10 minutes. Lift the jars out and drain upside down on a clean tea towel. Allow to dry.
  4. Microwave sterilising units (as used to sterilise baby bottles) are a quicker 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, bringing them to the boil in the microwave and then tipping the hot water out before filling with the preserves.
  6. Use Milton sterilising tablets in a large plastic tub.

Pickling in vinegar

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 of 50% 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 overnight in a cool place and then the resulting liquid drained off and rinsed the next day. Some low water veggies, such as beetroot can skip this 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 sterile 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.

Sauces, chutneys and relishes

If you are new to preserving, these are great preserves to start with. Good recipes will have the correct combination or amounts of the ingredients necessary to safely preserve the product. These ingredients will include sugar, vinegar and salt. They help preserve by creating conditions that prevent bacteria taking hold. Sealing jars while hot also helps create a vacuum seal, which stops air from entering. Of course, once opened, these preserves must be stored in the fridge.

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

Jams, Conserves and Marmalades

When making jams, conserves or marmalades you will almost certainly come across the term pectin. Pectin is a substance found in most fruits to an extent that, when at the right temperature (104oC), reacts with sugar to cause the mixture to set.

Most 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, or set. Some fruits naturally meet the necessary acid and pectin amounts (see below), 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. The fruit that you use should also be slightly under-ripe for maximum pectin content. 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 jam, but acts as the preserving agent in the jam. The sugar concentration creates conditions that discourage spoilants to flourish. The general rule is ¾ to 1 cup of sugar to every cup of fruit mix.

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.

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 to make a firm setting jam. Jamsetta, by Fowlers Vacola, is a powdered form of pectin available from supermarkets.

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. 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.

If your jam has set hard, 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.

Hot jam goes into hot sterilised jars and then sealed 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.

Small batches are best

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 heavy-based saucepans are also better for faster cooking. Of course, when bottling jams, small jars are better than large ones, as jams start to spoil as soon as they are opened, even when refrigerated.