Cans and lids and sterilizing seem like an awful lot of stuff to faff about with. This jam is meant to be made and enjoyed maybe even in the same day. It will make as much as you need. Just keep in mind that you will need to freeze it or use the contents in the fridge within two weeks or so.
Strawberries are a naturally low pectin fruit, and if you are harvesting them at their peak ripeness, or even over-ripeness, they contain even less pectin. That means that you may need to add extra citrus or even a cubed apple during cooking. I don’t mind a runnier concoction, so I don’t really worry about pectin amounts.
The ideal ratio for this strawberry jam seems to be to use 3/4 of the sugar amount to the fruit. That does not make sense. Try again: If you use 8 oz. of strawberries, you would need 3/4 of that amount in sugar…so 6 oz of sugar. The great thing about ratios is that you can make as much or as little based on how much fruit you have.
STRAWBERRY FREEZER JAM
8 oz. strawberries
6 oz. granulated sugar
Juice of a lemon (or grapefruit or lime in a pinch)
Wash fruit and get rid of stems. You can cut strawberries into smaller pieces, or leave whole if they are smaller and homegrown. Combine fruit, sugar and citrus juice in nonreactive pot (like copper). Cook over medium heat, stirring, until the strawberries begin to break down. You can smoosh a few here and there.
Raise heat and cook, stirring and keeping an eye on mixture. Skim any foam off with a wooden spoon, of course. You can use a jam thermometer, or just use intuition since it is just going to be kept in the fridge. Jam always starts off bubbling like mad and then calms down later. It is during this calm that the mixture begins to thicken and darken. You’ve got jam. 220 degrees F if you are being scientific about things. Actually that should be in centigrade for true scientists.
Pop into a jar or smother some on a croissant.