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Preserving Food

Most food grown locally will have a season when it is harvested, especially fruit and vegetables. If we want to eat them all year round then we have to preserve seasonal gluts. Some foods like grains, roots and apples will keep naturally if stored carefully. Others need to be processed to make them keep.

Methods of preserving include freezing, drying, bottling and making jams and chutneys. These pages are a starter guide to some of these methods, including

We have now tried out the new kilner jars. They can be used for bottling, but only with the water bath method, as the rubber seals will not stand higher temperatures.


For more information see books such as:-

  1. The Preserving Book by Lynda Brown. Published in 2010 by Dorling Kindersley. ISBN 978 1 4053 5985 6. Recommended price is £16.99 but Sustainable Thornbury may have some cheaper than this, or it may be cheaper from The Book People ( or at Amazon. 
  2. Home Preservation of Fruit and Vegetables by AFRC Institute of Food Research. Published by HMSO. First published 1929. Currently 14th edition from 1989. Available from Thornbury Bookshop (to order) for £8.95  (Amazon around £7)  ISBN 0 11 242864 9
  3. Any Good Housekeeping-type general recipe books (particularly older ones!). Look out for them in charity or second-hand shops.

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Where to get equipment

We are fortunate in Thornbury to have a several sources of preserving equipment.  One of the best places is the cookery shop Finishing Touches in St Mary Street. You will find good quality preserving pans and the owner will get in preserving jars and all the associated lids, rubber rings etc that you need – just ask!  They also sell funnels, muslin and equipment for straining fruit if you want to make jellies or clear juices.  Hawkins also have some equipment and so does Wildings' cookery shop.

You can get ready-spiced pickling vinegar and preserving sugar from Riddifords. 

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Bottling Jars

It can be difficult to get spare lids etc for older-type Kilner jars but there is a good website KilnerJarsUK which can supply both lids and jars. We have used them and they pack items well for the post. Our glass jars arrived in good order. Older Kilner jars are designed for bottling at high temperatures, with silicon rubber seals which won't melt at bottling temperatures.

Most shops don't understand the seasonal nature of preserving. The jars go out of stock quickly in the summer, so buy them ready in the spring. We have found them reduced to clear in the spring, presumably because they haven't sold any since last summer.

The new Kilner jars can be used for bottling fruit, but are NOT suitable for high temperatures, as the rubber in the lid seal is ordinary rubber and will melt. You can use them for bottling fruit using the water bath method, but not in the oven or pressure cooker. The water bath method is described in the Lynda Brown and HMSO books. You can buy the new-style Kilner jars in Thornbury in Hawkins, Finishing Touches, and Jasons. Make sure you buy preserving jars with two-part screw-on lids, and not storage jars with clips. Ask at Finishing Touches if you are not sure and they will order what you need. 

The new Kilner jars are also available from KilnerJarsUK and from John Lewis at Cribbs Causeway during the summer months. We’ve found that they don’t keep them on the shelves all year round which can be annoying if you want to make jam/chutney/marmalade etc and want jars or lids.  We have found some Kilner jars and lids at Hawkins in Thornbury. 

Other makes of preserving jars you can get include:-

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Jam Jars and Jam pot covers

If you use ordinary jam jars and want to buy some (rather than just save your own), you can buy them at the cookery shop Finishing Touches in Thornbury. They also sell jam/chutney pans, jam pot covers and bottles.

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Here are general instructions for various preserving tasks:-

Sterilising jars

To sterilise your jars and lids you have several options

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Adding pectin to jams

Jams need pectin in order to set. If your fruit has low pectin (see the table below) then you will need to buy preserving sugar or pectin to add, or add some lemon juice, citric acid or fruit with high pectin.

High Pectin

Medium Pectin

Low Pectin


Fresh Apricots

Late Blackberries


Early Blackberries








Some Plums






Freshly picked raspberries

Sweet Oranges





Seville Oranges



Tart cooking (or crab) apples



Use dry, fresh fruit and make on the day of picking if possible, as the pectin reduces even if left overnight. Frozen fruit is excellent but will have lost a little pectin so just add a little more fruit or lemon juice.

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Bottled Tomatoes  - Oven Method

Use ripe tomatoes

1.    Preheat oven to 150°C / 300°F/Gas 2/Fan 140°C.

2.    Sterilise jars and tops.

3.    Cut the tomatoes in half and squash them into the jars so that they are covered with their own juice, up to 1 inch from the top of the jar. The end result will then be ready for use in the winter in stews, soups and sauces.

4.    Put on warm lids and metal screwbands. Tighten the screwbands then loosen them ¼ turn. Plastic screwbands should be left off, as they may melt in the oven.

5.    Pack jars 2 inch apart on a baking tray lined with several layers of newspaper.

6.    Put into oven for approx 1hr to 1hr 10min. The liquid in the jars should have been boiling for about 10 minutes. 

7.    Remove from oven and immediately screw down the lids tightly – plastic screw bands should be fitted and screwed on tightly at this point. It is vital that no air is allowed into the jars at this point, so the top of the jar is filled with steam. If air is accidentally allowed into a jar then put the jar back in the oven to boil for another 10 minutes.

8.    Leave to go cold for 24 hrs or so. The steam will condense in the jars and leave a vacuum that holds the lids on.

9.    Check the lid seals by gently unscrewing the screw band or removing the spring clips. Using your fingernail, see if you can gently prise off the lid. If it remains firmly in place it is OK, and you can clean the outside of the jar and the screwband, so it does not go mouldy on the outside.  If the lid lifts easily, the heat processing was not successful. Store the jar in the fridge & eat within 2 weeks.

10.    The screwband can be loosely refastened.

11.    Store in cool, dark place

NB Bottled plums are prepared in the same way as tomatoes. Half & stone fruit after washing in cold water before following method as above.

Whole Tomatoes

To bottle 1kg whole tomatoes, use above method but first toss in a bowl with 2tabsp lemon juice, 2 teasp salt, 1tsp caster sugar. Pack tomatoes tightly without squashing. Divide any remaining juice between the jars and seal.

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Bottling Fruit - Pressure Cooker Method 

1.    Use prepared, warm bottles & lids.

2.    Pack fruit in bottles without bruising

3.    Dip lids and rings in boiling water and place on jar

4.    Fill with boiling water to 1in of rim. Shake gently to remove bubbles

5.    Put on lids & screwbands & tighten. Loosen ¼ turn. Tie cloth or string around each jar to prevent them from touching.

6.    Pack in pressure cooker on rack/trivet with 1in water. The rack is important as otherwise the jars will crack.

7.    Bring to boil, letting steam escape for a bit.

8.    Add small (5psi) weight & bring to pressure in 5-10 min.

9.    Cook for 1 min at pressure

10.    Allow to cool for 10 min

11.    Remove from pan, and quickly screw down lids. It is vital that no air is allowed into the jars at this point, so the top of the jar is filled with steam. If air is accidentally allowed into a jar then put the jar back in the cooker and process again.

12.    Test for seal when cold, clean the jars & store in a dark place.

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Recipes - Jam

Blackberry jam

Blackberries do not have a great deal of pectin, the ingredient that ensures a decent set in jam. That is why lemon juice, citric acid or tartaric acid is added during cooking. I prefer to use lemon juice for my pectin, but gooseberries and apples can also provide the necessary pectin.

Pick over the blackberries, wash and put them with then lemon juice (or tartaric acid) and water into a pan. Simmer gently until the blackberries are cooked and the contents of the pan well reduced. Add the sugar, bring to the boil, stirring, ensuring that the sugar is properly dissolved, and boil rapidly for about 10 minutes, or until setting point is reached. Pot and cover in the usual way.

(Makes about 4.5 kg or 10 lbs)

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Blackcurrant Jam

My favourite jam is blackcurrant. Blackcurrants have loads of pectin and so do not need a boost when made into jam.

Remove all stalks, wash fruit and put into a pan with the water. Simmer gently until the fruit is soft and the contents of then pan well reduced, stirring from time to time to prevent the fruit from sticking to the bottom of the pan. Add the sugar, stir until dissolved and boil rapidly until setting point is reached. Pot and cover in the usual way.

As the skins of currants tend to be rather tough it is important to cook the fruit really well before adding the sugar.

(Makes about 4.5 kg or 10 lbs)

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Rhubarb and Orange Preserve



  1. Thinly peel oranges and lemon, removing pith and pips.
  2. Slice pulp into a pan with finely cut peel.
  3. Wash and dry rhubarb, cut up finely and add to pan with the sugar
  4. Stir over a low heat until the sugar has melted and then boil fast until the preserve sets.

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Recipes - Chutney

Plum Chutney

Makes approx 1.35kg (3lb), 3 large jars
Takes: 1hr 50min – 2hrs
Keeps; 12 months

Halve the plums, remove stones, and quarter the fruit. Core peel and dice the apples into bite-sized pieces. Peel and finely slice the onions.

Put all ingredients into a preserving pan, bring slowly to the boil, stirring to dissolve the sugar.
Simmer gently for 1½ - 2 hrs until a wooden spoon drawn across the base of the pan leaves a trail. Stir frequently towards the end so the chutney does not burn.

Chutney should look thick and glossy. Check the seasoning, add more salt if necessary and pot into warm sterilized jars, making sure there are no air gaps.

Cover with discs of waxed paper, seal with cellophane covers and elastic bands, or non-metallic or vinegar-proof lids. Label and store in a cool, dark place.

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Spiced Rhubarb Chutney

Makes: approx 1.4kg (3lb), 3 large jars
Takes 1hr 20min
Keeps 9 months

Put rhubarb, apple and onion in preserving pan. Add 1-4tbsp water and cook on a low heat until the rhubarb softens (about 10 mins).

Stir in ginger, curry powder, onion seeds, salt. Pour in half the vinegar and simmer gently for 30-40 mins, stirring occasionally.

Dissolve sugar in remaining vinegar in a bowl and add to pan. Simmer gently until mixture begins to thicken, about 10-15 mins, stirring continuously so it doesn’t burn.

Ladle into warm sterilized jars, making sure there are no air gaps. Store in a cool, dark place to allow flavours to mature (at least 1 month) & refrigerate after opening.

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Luxury Fruit Chutney

  • 400 ml cider vinegar
  • 360g dark muscovado sugar
  • 600g orange juice
  • 200g sultanas
  • 140g dried dates, pitted and chopped
  • 140g dried apricots, chopped
  • 140g prunes, chopped
  • 120g currants
  • 100g onion chopped
  • 40g dark rum
  • 20g crystallised ginger (optional)
  • 1/4teasp ground allspice
  • 1/4teasp ground ginger
  • 1/4teasp ground cinnamon
  • 1/4teasp& sea salt
  • 1 tbsp cornflour
  • 3 tbsp water
  • Combine all ingredients, except the dark rum, in a large, heavy bottomed pan (min 3 litre capacity). Stir well & leave overnight, covered. Next day, uncover & bring slowly to gentle boil. Stir well & often. Reduce the heat & simmer for approx 1 hour until thick, stirring occasionally. Add the dark rum, stir in gently & remove from heat. Pour into warm, sterilised jars & seal. Keep for approx 1 month before eating to let flavour develop.

    NB, can use other spirit eg brandy or omit if liked.

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    No-Cook Date and Apple Chutney

    Mince together (or use food processor to grate/chop), add sugar & vinegar. Leave to stand overnight
    Pot in sterilised jars.

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    Pear Chutney

    Makes approx i.35kg (3lb) (4 medium jars)
    takes 2:30 – 2:45 hours and keeps 12 months


    Put all the ingredients into a preserving pan or a large heavy-based, stainless steel pan. Bring slowly to the boil, stirring to dissolve the sugar.

    Reduce the heat and simmer gently, uncovered, for about 2 hours or until the mixture thickens and takes on a dark caramel colour and a wooden spoon drawn across the base of the pan leaves a trail. Stir frequently towards the end of the cooking time so the chutney doesn't burn.

    Ladle into warm sterilized jars with non-metallic or vinegar-proof lids, making sure there are no air gaps. Cover with waxed paper discs, seal, label, and store in a cool, dark place. Allow the flavours to mature for at least 1 month, and refrigerate after opening.

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    Recipes - other preserves

    Lemon Cheese



    1. Using a glass jug or bowl (e.g. Pyrex), stand the jug in a pan of simmering water, making sure that the water does not flow into the jug. Put the butter and sugar into the jug and stir until the butter has melted and the sugar dissolved.
    2. Squeeze the lemons and add the juice to the jug. NB if you want, you can add lemon zest also.
    3. Beat the eggs separately and add to the jug. Stir the mixture constantly until it thickens. The lemon cheese is ready when the mixture falls from the spoon in thick, separate drops.
    4. Place in a clean, warm jar and store in a refrigerator when cold. It will keep for approximately 2 weeks.

    This makes about 1 lb of lemon cheese.

    Gooseberry Curd


    1. Put gooseberries in a pan with 100ml water and the lemon zest. Cook gently until very soft, then rub through a nylon sieve.
    2. Put the butter, sugar, lemon juice and gooseberry puree into a heatproof bowl over a pan of simmering water. As soon as the butter has melted and the mixture is hot and glossy, allow it to cool a little (it should read no higher than 60C on a sugar thermometer).
    3. Pour in the eggs through a sieve and whisk in with a balloon whisk.
    4. Stir the curd over a very gentle heat, scraping down the sides of the bowl every few minutes, until thick and creamy – 9-10 minutes. (The temp on a sugar thermometer should reach 82-84C)
    5. Pour immediately into warmed, sterilised jars and seal. Once opened, keep in the fridge and use within 4 weeks.

    This makes about five 225g jars.