Freezing tomatoes is the easiest way of storing them, if you have the freezer space, but it does have some drawbacks. The freezer basically slows down the natural process of ripening then degradation that occurs in fruit and veges. For many vegetables, freezer life can be extended significantly by blanching (partial cooking followed by rapid cooling). However, this process is not very practical with tomatoes.
In our experience, tomatoes put straight in the freezer will last up to a year or more. But we wouldn''t recommend storing them for more than two seasons. Try to use them before next year''s crop starts ripening.
How to freeze tomatoes:
Step one: Prepare the tomatoes by cutting out any bad bits, and removing the inedible bits on the top and bottom of the fruit.
Step two: Cut the larger tomatoes into halves or quarters, and lay out on a tray. Pop the tray in the freezer.
Step three: After a few hours, when the tomatoes are at least partially frozen, bag them up and store in the freezer.
The whole and cut tomatoes should not stick together if prepared and frozen in this way. Now you should be able to go to the the freezer rather than grabbing a can every time a recipe calls for tomatoes.
We use bottling as a generic term to refer to preserving tomatoes in bottles, jars, and even cans (if you have the right equipment). We are going to describe how the process works using jars, but you can easily adapt it for other kinds of storage vessels.
You can buy preserving jars, but it can be quite expensive. Second-hand jam or pickle jars are usually suitable, as long as they have a metal lid that can be sealed air-tight.
How to preserve tomatoes:
Step one: Prepare the tomatoes by cutting out any inedible bits, and chopping them up finely or blending in a food processor. Some people dip whole tomatoes in boiling water first then remove the skin, but this step is optional and a matter of personal preference.
Step two: Bring tomatoes to the boil and simmer at least 15-20 minutes while you prepare the next step.
Step three: Clean your jars and lids and then heat them up by placing in boiling water. This process will help kill any bugs and will ensure the jars are hot so they don''t crack when you put the hot tomato mixture in. Also sterilize a soup ladle or large spoon with boiling water.
Note: Ideally you should sterilize preserving jars/bottles in a pressure cooker (which can get up to temperatures in excess of boiling). This process ensures all bugs are killed and prevents problems such as botulism. However, the risks of such problems are low with tomatoes due to their high acidity.
Step four: While the tomatoes are still on the stove over a low heat, pick up a jar with a tea towel or oven mitts (it will be hot) and use the soup ladle to fill the jar right to the top with the tomato mixture. There should be as little space as possible at the top of the jar. You may even fill it to over flowing and then clean the outside of the jar later.
Step five: Screw the lid on tightly and leave the jar to cool, after about 20 mins to 1hr the lid should "pop" down (most jars have a "button" on top to indicate it is sealed). If the lid pops down then you know that no air can get into the jar and spoil the contents.
Tomatoes stored in this way will keep almost indefinitely if the jar remains sealed.