Monday, 18 January 2010

Making Jam ~ general instructions

Notes revised, 2nd February 2011
Making jam is straightforward but somewhat time-consuming.  It also requires a reasonable amount of attention so I allow a few hours each time I cook up a batch in a stockpot-sized saucepan. That sized pot will take about four kilos of fruit, which is enough to make the effort worthwhile. The reward is that you then have a supply of a dozen or so jars of jam which will last the household for weeks and weeks!

It's a good idea to write down your quantities and ratios in a notebook so that you can be sure of being consistent, or of being able to do it differently if you want a different result next time.  For this reason I always label my jars with the type, batch number and date.  It has turned out to be surprisingly useful.

For recipes for different sorts of jams: gooseberry, raspberry, plum, and apricot, refer to the article linked to below:
For my marmalade recipe refer to this link:
For the bottling process itself refer to my article about using pop-top jars.

Here is a general method: 
  • Get your jars all clean and lined up.  I've found that one kilo of fruit will make between two and three jars of jam of the sort that originally held about 400 grams of whatever it was they first contained.  This will give you a rough idea of how many jars you'll need. 
  • Wash and prepare your fruit for cooking, removing any stones, cores or skins that you don't want to eat.  An exception to this is plums, the stones and skins which I remove after they have floated free in the cooking process - refer to notes below. Make sure you also remove any 'bad' bits.
  • Weigh your fruit once you've prepared it as much as you are going to prior to cooking, and write down your total.
  • Work out the sugar needed according to the ratio you decide on.  Again, refer to the following article for the schedule I use.  Mostly, five parts of fruit to four parts of sugar is about right, or if you prefer it a little sweeter, six parts of fruit to five parts of sugar. Write down the ratio you decide on and the total needed. To check your sums, the quantity of sugar should usually be less than the amount of fruit.
  • Weigh your sugar and put it to one side as you won't need it immediately. 
  • Work out how much water you'll need and put it in the pot.  Generally speaking jam requires only a very small amount, say about half a cup per kilo of fruit.  More than that and you'll find it takes a long time for the liquid jam to reduce enough to set. Most fruit turns into a watery pulp very quickly, and can then cook in its own juice. 
  • Add your fruit to this small amount of water bit by bit.  This gives the fruit time to contribute its own moisture and get mushy before adding more, which makes it much easier to manage and reduces the possibility of it catching on the bottom of the pot. 
  • Keep stirring it so that it doesn't catch. If it does catch, immediately decant fruit into another container and clean the burnt area out of your pot before putting the fruit back into it as the burnt flavour can easily ruin your jam, which should taste delectable.
  • Remove any stones and skins that weren't removed prior to cooking, such as with plums. These float free in the cooking process. Remove them either by fishing them out with a slotted spoon in conjunction with a dining fork, or by sieving them. I put the waste stones and skins into a sieve placed over a large bowl to collect any residual juice. You'll note that I haven't yet got to adding the sugar; this is because it's wasteful to discard sweetened stones and skins but also because everything can rapidly become very sticky, and yes, I've made this mistake!
  • Your fruit will now be a fairly even liquid. Bring it to a nice boil.
  • Add your sugar - gradually.  It will look an astronomical amount but if you have done your sums correctly you will know that it is the right amount - which demonstrates the value of having written everything down! Stir briskly over a medium heat taking care not to allow undissolved sugar to sit on the bottom of the pot where it can easily catch.  Again, if it does catch, immediately empty the pot and clean as above.
  • Bring it back to the boil and keep it there, making sure to keep stirring it while the sugar dissolves.  You can turn up the heat at this stage to keep up that brisk simmer.
  • Add a knob of butter to reduce any foam that forms on the surface.
  • The fruit will need to simmer at a rolling boil for some time before it becomes ready to set. The length of time can depend on the amount of water used as well as the amount of natural setting agents in the fruit.  Keep it moving. This can be a good time to catch up on some reading while keeping the fruit moving or of watching something on the tele if you have one in the kitchen. 
  • As your jam nears readiness for bottling put your jars into a sink full of really hot water, and the lids into a heatproof bowl filled with the same so that they are ready for action. 
  • Refer back to the guidelines in the article on pop-top jars
  • Testing for setting readiness: the usual test is to put a small spoonful onto a saucer and leave it to cool somewhat; once cooled, you draw a spoon across it and if it's ready to set the surface of the jam will have formed a 'skin' which will wrinkle as you do so. However, I've never got the hang of this! I go by the look and the sound of it. The bubbles begin to resemble ball bearings, which get bigger, some approximating marble size, and will hiss and 'plup' a little. It can take quite some time for it to reach this stage, but it will.  The boiling jam will still look unbelievably runny.  Later note: this is certainly true for plum jam whereas apricot and gooseberry jam need to become somewhat more porridge-like before they are likely to set properly.  If you're doing this for the first time you might want to do a smallish batch first to get a clearer idea of what works best for you. 
  • Once this point is reached your jam is ready to bottle, so go to it! You needn't fill the jars to the very top, but near to it is good and the pop-top lids will click down more readily. I stand filled and capped jars straight back into the sink of hot water but do not immerse them above their shoulders, so that no water seeps in before they properly seal.
  • Wash the jars as soon as possible as they will be sticky!!!
  • Your jam should set overnight. It can be useful to put a small quantity into a jam dish which will enable you to see easily whether it has set of not.  The whole batch will be much the same.  The jars can be tested by tilting or turning them upside down. The jam shouldn't slide around too much, or may set completely.  If it does, this can usually be rectified by re-boiling it.  Some recipes recommend the addition of Pectin to address this problem, which I haven't used, but it is available at supermarkets, so it is not difficult to get or mysterious.
  • The only thing left to do is to label and store your jars - well done!

More of my articles about jam and preserves as well as other food articles can be found listed together via the link below:

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