Preserve 72 Jars of Fruit in a Morning

It’s wonderful to be able to preserve 50kg (110lb) of fruit in a morning and have the 72 jars stored for the year’s desserts and breakfasts. This method has been perfected over thirty-five years and may be suitable for others out there who enjoy bottled fruit but have only learnt to make small batches in a hot kitchen.

24-quart jars are placed in a 60 litre (16 gallon) drum used as a water bath and this is placed inside a 200 litre (44 gallon) drum used as a wood furnace. The water bath comes to the boil in an hour, the jars are left to cook for 10 minutes and then the batch of jars with their fruit are removed and left to cool.

This site is for those who like bottled fruit, have access to high-quality bulk fruit and can find the drums cheaply in their town or city. It is also suitable for those who have a cottage industry making preserves and who want to expand their range.


Requirements. You need;
(1) A 44 gallon open-top drum with a hole cut out in the bottom to make a furnace. Cut the hole with a cold chisel which is a toughened chisel able to cut steel;
(2) A 16 gallon open-top drum. These are called grease drums and a used one can be obtained from large users of machinery. Cleaning the new drum is easy if the grease has a melting point lower than that of boiling water. Just place the drum on the bricks in the furnace, fill with water, boil and then skim off the oil and grease. If the grease does not shift this way then you have to wipe it out with rags and wash it out with warm, grease-shifting detergent. Clean, open-top drums can be bought online;
(3) A firm round disc with holes in it that fits nicely at the bottom of the smaller drum. A perfect one is the steel disc found across the lint sieve in the older New Zealand Fisher and Paykel tumble clothes driers. If you cannot find one, have a stainless steel one made in an engineering workshop. It needs to be 33cm in diameter drilled with 1cm holes. Do not use weather treated wood as a substitute because you don’t want wood preservative circulating around the jars. Don’t use particleboard, as it will break up in the first boiling.
(4) Stiff wire handles that go to just over the top of the drum are attached to the disc. This is the ‘basket’ on which the 24 jars are stacked in three layers of 8 jars.

You also need four firebricks. These bricks have been made to resist heat and may be bought from a demolition yard. These are placed in two stacks on their edge and are the support for the smaller drum and make up the firebox. Concrete bricks crack with the heat and modern bricks are too narrow and brittle to use. If you cannot find any you will have to go to an engineering shop and get them to make up two boxlike supports for the small drum. Make them 24x24x10cm out of welded angle iron.

The common Agee preserving jars come in two types; newer ones and more thick-walled older ones. The older type has a thick surrounding ledge just below the screw thread and these require gold coloured screw bands. The Gold bands that are sold also fit the American Mason jars. The newer preserving jars have green screw bands. The screw bands and lids are available from leading supermarkets in New Zealand. If they are not there, ask your supermarket to order them in from the suppliers; Contact The jars are sometimes available on the TradeMe website or you will need to advertise for them. You will need approximately 72-quart jars for 50 kg of fruit if it is stacked in the jars. If fruit like Damson plums are just poured into jars, then you’ll need about 90 quart jars for 50kg fruit. You can preserve fruit in the smaller half-size jars but they take up a lot of room in a pantry.

The wood that is needed to fire the drum can be off cuts from a timber yard or old cracked planks from a demolition yard or you may have some dry, pruned branches from your trees. You will need a hatchet to break up the wood.

Buying Fruit
If you are going to bottle 50kg of fruit in a morning then use fruit that you do not have to peel.
Use only hard, new fruit and this can be bought from local orchards, farmers’ market, auction houses that deal in fruit and vegetables or from online orchards. Do not put soft, over-ripe fruit in jars as these become mush when cooked and they also affect the ability of the jar to seal. See below. If you intend to bottle fruit for a local tourist lodge, choose fruit that you cannot buy cheaply in cans. Nectarines, Damson plums, Fortune plums, greengages or the first class apricots that are available would be ideal. Bottling for a tourist lodge would be great in that you can go back there for the jars.

The Site
For the setup to be stable, the site where you are placing the drums has to be firm and dead level.
The small drum is filled with boiling water and jars till the surface of the liquid is just 3-4cm from the top of the drum so if there is any lean on the small drum, there is the risk that something will tip. As I live in town on a hill I have dug a small, circular depression in the back garden, used a spirit level and a small plank to make it flat and then bricked it over.

Filling The Jars
Wash the fruit and put the jars through a dishwasher or clean them thoroughly in a sink. Large plums are just halved and the pieces stacked nicely in the jar. The small stones may be left in as these can give an almond flavour to the cooked fruit. Apricots are stoned as the larger stones take up too much room in the jar. Peaches and pears would have to be peeled and the fruit sliced. Small plums are just poured into the jars. Tomatoes can be squashed into the jars with a bottle. Do not overfill the jars as the lid wont seal if fruit is pushing up from the underside. Eat or discard over-ripe fruit, as this does seem to cause the lids not to seal. There are dissolved gases in the over-ripe fruit that causes pressure to build up in the heated jar. Just pour one tablespoon of sugar on top of the fruit. If you add more sugar, this will just sink to the bottom of the jar and form candy when it is all cooked.

Fill the jar with water out of the hot tap. This ensures that the water in the jar does not have any dissolved air in it. This water does not have to be hot- it just needs to have passed through the water heater in your house to remove its air. If you use water out of the cold tap, then a large pressure builds up in the jar and the lids are less likely to seal when they cool. Make sure that you fill the jar completely with water and sluice all of the sugar off the rim and into the jar.

It is best to have the old and new jars placed separately so you do not mix up the two different screw bands. If the screw band is not tightened enough, juice from the jars spays when you lift it from the boiling water or, if you put all your force into tightening it using rubber gloves that give a slip free grip, very little pressure will be released in the boil-up and some seals will buckle up as the jars heat.

Tighten the screw bands thoroughly using dry hands. Ensure the band is not cross-threaded and when it is on, look carefully where it overlaps the seal at the rim. If there is a gap, it is not screwed on properly or, the band has been deformed and needs to be thrown away.

In 2012, 2013 I did slower boil-ups. I only burnt one cardboard box at the start, relied just on wood for the burn and time for boiling then took an hour to 1 hour and 10 minutes. I took the jars out after another 10 minutes. In the eight batches (192 jars) there was not one failure. In 2014, I used rubber gloves to tighten the bands and in each batch three or four seals buckled up with the pressure and I had three failures in the 96 jars cooked. Failure occurred because when the seals buckled up, three bands deformed under the rapid movement of the seal and air then escaped into the jar when it cooled. If a seal(s) does buckle up, leave the jar alone when you take it out of the drum. Most of them will be fine.

Firing Up The Batch
Place the small drum on the bricks- about 27 cm apart so that the rims of the drum sit on the bricks. Put in the disc then place evenly eight-quart jars on the bottom then repeat with another sixteen jars. Fill the drum up with cold water till 3-4cm from the rim.

Light the fire and use pinecones or small pieces of wood to get the most heat into the walls of the small drum. Tear up one cardboard box to warm the water at the start then only use wood. After an hour or so, the water will boil as a moving shimmer over the surface and large bubbles will rise, it will not come to a rolling boil.

Don’t get it really hot by using many cardboard boxes so that it reaches a boil in 30 minutes. Then the jars won’t have time to cook and there isn’t enough time for the pressure in the jars to release in the drum.

Note the time when boiling happens and then stop feeding the fire after 2-3 minutes. The fire should be well down when you take out the cooked fruit- ten minutes from the time of boiling. Do not exceed this time, as the fruit will just turn to mush. During the cooking, the water does get a little brown from iron in the drum but this does not affect the sealed fruit.

Taking Out The Jars
Have one person put on leather gloves. This person lifts up the entire batch with the wires. There are rubber gloves available that have a canvas inner and are sold for handling chemicals. They are the best for pulling out the hot jars. See your safety or rural supplier. These thick rubber gloves are a necessity for safe handling of the hot jars. Always have a bucket of cold water handy. Put some planks on the ground a small step away onto which you will put the hot jars. The person with the leather gloves then lifts the whole batch so that the top row of jars are just out of the water so that they can be picked out by the other person. Lift the jars on opposite sides of the drum so that the weight remains balanced. Do all of this rapidly as the holder of the jars must remain steady for about five or ten minutes as you unload the drum. Cool your fingers in the bucket of water if needed. Remember your school physics in that a jar under water weighs a lot less and the batch of jars is surprisingly easy to lift.

You might like to practise this procedure before the drum is fired up so that you get a feel of the effort and time involved and you are just dealing with cold water. You MUST lift out the jars from opposite sides of the small drum, two at a time so that the weight remains balanced.

Preparing For The Next Batch
Remove the bulk of the hot water by scooping it out with a pot since the cold jars of the next batch will often crack if they are placed in the boiling water. Pour the hot water onto weeds in your garden. Hose in cold water until the water is warm. Stack the next batch for firing and refill the small drum with water. Move the hot jars onto cardboard in the shade to cool. When you finish up completely, put the small drum on the bricks over the embers to drive out the water at the bottom edge, as it will rust out if you don’t.

Reasons For Failure To Seal

Now, after thirty-five years of preserving by this method, by carefully attending to the factors below, you can get all jars in each batch to seal. When jars are sealed, the lids depress with the vacuum in the jar. Most of them depress fully but sometimes, one or two in a batch of twenty four only partially depress after four or five hours. Leave them, as they normally fully depress when the jars are cold.

 Unsealed jars occur because;

  • Water out of the cold tap is used to fill the jars.
  • The wrong screw band is used for the jar or the screw band is cross-threaded.
  • Two seals are placed on one jar. This happens because the seals stick together when they come out of the packet. If children are helping then this can easily happen.
  • The rim of the jar is chipped.
  • The seal is placed on sugar sitting on the rim of the jar.
  • The screw band is deformed or is too rusty to screw down.
  • Over-ripe fruit is bottled.
  • Jars are overfilled with fruit and the seal has no room to depress.
  • The screw band is not wound tight enough and hot juice sprays out of the jar when it is lifted from the drum

If you do intend to sell your jars, put your label on the seal as it will be hard to recycle the jar if labels are firmly stuck to jars.

Storing The Cold Jars

It will take six or seven hours for the jars to cool and the seals to depress. Remove the screw bands and clean them in soapy water. Sugary juice will have seeped on their screw thread and this will rust easily if the bands are not washed. Store the bands in a cupboard away from damp air in the garage. Wipe the top of the jars with a sponge to clear away this sugary remnant, as fungus will grow over the top of the glass if you don’t.

Store the drums under cover as they rust easily if kept out in the weather. Next year wipe the inside of the small drum with steel wool before preserving.

Opening the Jars
Preserving jars chip on the rim and become ruined if they are opened with can openers. They should be opened with the tip of a spoon being levered over the fingers. If the seal completely covers the opening, a large knife should be stabbed through it and then it can be lifted off.

The fruit is preserved in very light sugar syrup and so the tartaric acid in the fruit needs to break down somewhat. Storing the preserves for two months takes a lot of the tart flavour out of the fruit. The best-preserved fruit, like stored wine, develops its flavour over a year or more. Greengages cooked for 15 minutes instead of 10 will be slightly mushy, but they have a wonderful almond flavour.
A Social Event
In 1978 I organised a church picnic at a friend’s house and asked people to bring their jars, their families and I would supply the tomatoes from a field at Lincoln University. The children and the women squashed the tomatoes in with sticks, the men stood around the fire and put in and pulled out the jars, drank beer, tended the barbecue and we did if I remember about 140 jars.
I met my wonderful wife at that day and we had a great time for thirty years.

Perfecting A Method
Off the Taranaki coast, newcomers to yachting will launch their sailing dinghies, especially the well-liked 470, and over two or three summers, the helmsmen will progressively learn to position their boom and tiller so that safe fun and speed happen on the water in all types of weather. With skill they sail through squalls or when a cold southerly front rolls in from the sub Antarctic.

However for me, only on two days/year, have I been able to change and assess the many factors that influence the mass bottling of fruit, in a grease drum over a fire. So its taken me thirty-five years to know; how best to use cardboard for the boil-up, how tight to screw down the bands or to use over-ripe fruit etc.

Today, as I go beyond my sixty-fourth year, you can see from the colourful jars in their bespoke oak case*, it has been worth it. There are subtly flavoured plums and apricots to enjoy all year round - picked in the sunny orchards of Central Otago.

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