Washing, crushing and cutting
Updated
You need
- A colander and cold running water
- A potato masher or a pastry blender for soft fruit
- A knife and board for firm fruit
- A sieve or food mill, if the fruit has seeds you do not want
The steps
Preparation decides more about the finished jam than anything that happens at the stove, and almost all of it is irreversible by the time the pan is hot. The sequence below is ordinary; what matters is doing it before the fruit is softening rather than alongside the cooking.
- Wash all the fruit thoroughly under running water. Do not leave it to stand in water.
- Remove stems, skins and pits from the fruit that needs it, and stems and blossoms from berries.
- Crush soft fruits and berries. Cut firmer fruits into small pieces.
- Put seedy berries through a sieve or a food mill if the seeds are not wanted in the finished product.
What "crush" is doing
Crushing is not chopping and the difference shows in the jar. It is about releasing juice and pectin from fruit that is going to hold some of its shape, which is why the published guidance says crush rather than puree and why a blender produces a different product entirely.
It is opening the fruit so sugar can get in and water can get out. A whole berry in a jam will sit in syrup rather than becoming part of it, which is the difference between a jam and a poorly made preserve.
Where the peel and core go
What you discard is not all waste, and one part of it is the most concentrated pectin source in the kitchen. Worth knowing before it goes in the bin, particularly with a low-pectin fruit where the alternative is buying commercial pectin to compensate for something you threw away an hour earlier. The trimmings go into a second pan with water rather than into the bin.
If the product has no added pectin, into the pot. Extension guidance notes that peels and cores add pectin to the juice during cooking, so skins are structure here rather than waste. That is on the pectin is in the parts you were going to throw away.