Making Jam: The Basics and Equipment
One of the best things about jam making is that it is pretty light on specialist equipment. You really just need a pan, some jars (easily recycled from other things), fruit and sugar. Other equipment is useful, but definitely not required.
Optional equipment for jam making:
Jam funnel - for getting jam mess free into jars
Wax circles - for limiting condensation inside the jars and helping to control mould
Candy thermometer - to check the jam reaches the setting temperature of 221f/105c
Jars and Sterilising:
Sterilising is a crucial step in the canning process. How you sterilise and process your jars and finished products depends on what you are canning. For acidic foods (which jams fall into), you need to ensure a clean and sterile enviornment as much as possible (for non-acidic foods, an entirely different process is used).
For jam making, the I always find that the bit I like least in jam making is the sterilising of the jars. Jam is naturally pretty resistant to growing anything nasty. It is highly acidic, both from the sugar and the fruit in it, and it also has a chemical makeup that doesn’t leave a lot of room for bacteria to grow. That said, certain mildews and moulds do thrive in jam jars, and while they aren’t a kind that particularly will harm you, its best prevent them through sterilising your jars.
Generally speaking, the method for sterilisation is as follows:
wash your jars in hot, soapy water
rinse in clean water to remove and soap residue
place on a baking tray and heat in oven to 160c/320f.
boil lids as they usually aren’t oven safe
Alternatively, if you have a dishwasher that has a steam cycle, simply run the jars and lids through that, let them cool slightly and use them one by one.
Do I Need to Water Bath Can Jam?
In many recipes, particularly American ones, you will see that most writers recommend water bath canning the jars. Now, we are going to go into this method in more detail next lesson, but in essence the method is after the jam is bottled, you then boil them for 5-10 minutes in a water bath. If you jam and jars had cooled slightly before you filled and sealed them, you may not get a tight seal and you may have introduced bacteria into the jams. While this isn’t always necessary with jams, it does help to get a good seal and double ensure your jam is as bacteria free as possible.
The Magic of Pectin
Have you ever made jam and wondered what went wrong? Rather than the perfectly pert glob of fruit and sugar perched on your knife as you move it from the jar to your toast, you have a runny mass of syrup that should really only be handled with a spoon? Well, thats because you didn’t have enough pectin to turn your syrup into jam.
Pectin is a long chain carbohydrate found in most fruits in varying amounts. It is in its highest concentration in pips and skins and in underripe fruits, and creates a grid like structure that traps liquid inside it, giving jams their perkiness.
Though it may be naturally present in most fruit, pectin needs the right conditions to be able to do its thing and make jam. It needs an acidic environment, sugar and a temperature of 221f/105c to get those structures to form. If you’ve done all of those things and your jam still hasn’t set, its probably because your fruit doesn’t have enough pectin in it.
tart, underripe apples
plums (but not Italian variety)
grapes (Eastern Concord variety)
There are a number of ways you can add pectin to your jam to help give it its get up and go. You can either add some high pectin fruits to your jam - a cooking apple regularly makes its way into my strawberry jam without anyone being the wiser - or you can add additional pectin though using specialist jam sugar (found in most supermarkets), adding bought pectin in liquid or powdered form or making your own (see this post).
Storing Your Jams
After you’ve made your jam, providing the jars and contents were hot, you should get a good seal on the jar. A vaccum is created when the hot contents cool, resealing the jars and making them airtight. This helps keep out any nasties. If your jar doesn’t seal, you can try boiling the jar in water with the contents in.
Jam usually can be stored in sealed jars for 6 month to a year on the shelf.