This is almost the end of the British strawberry season. My sister, who is visiting us for a week, wanted to eat some - prompting me to buy some. We got a small box with our groceries yesterday. Strawberries have a short shelf life and so after eating as many as we could, we still had enough remaining to make some jam. Earlier this summer when my mother-in-law was visiting us, she had "jammed up" some strawberries and so i decided to experiment with her recipe. It was a old rainy day and so strawberry jam sandwiches with some butter made all the difference.
Here is how i did it: i removed the stalks from the strawberries and chopped them up - or rather sliced them because i like to encounter some of the heart shaped fruit in my jam. Then i mixed it with some sugar in a bowl. So it was around a dozen strawberries and about 3 or maybe 4 tablespoons of sugar. And squeezed the juice of half a lemon on top. I stirred it around in the bowl and then transferred the mixture into a saucepan. This was then simmered on low heat till the sugar melted. I was getting impatient so i turned up the heat a little. The entire mixture then comes to a boil. At some point in the whole process the mixture starts thickening. Recipes on the internet generally suggest the cold saucer test - and i think you will have to do so for large batches that you would want to preserve. And i guess in that case you will have to measure the ingredients and worry about the correct process. But i can guarantee that for a small quantity of fruit that you want to put to good use so that you consume it before it goes bad, this works and works well. So after having some jam sandwiches at tea time, we will polish the rest off for dessert - vanilla ice cream with a dollop of jam to top it.
So just out of interest - here is the science behind it. I found this on a website called www.infoplease.com. Strawberries contain pectin. Pectin is any of a group of white, amorphous, complex carbohydrates that occur in ripe fruits and certain vegetables. Protopectin, present in unripe fruits, is converted to pectin as the fruit ripens. Pectin forms a colloidal solution in water and gels on cooling. When fruits are cooked with the correct amount of sugar, and when the acidity is optimum and the amount of pectin present is sufficient, jams and jellies can be made. In overripe fruits, the pectin becomes pectic acid, which does not form jelly with sugar solutions. Fruits rich in pectin are the peach, apple, currant, and plum. Commercial preparations of pectin are available for jelly making. An indigestible, soluble fiber, pectin is a general intestinal regulator that is used in many medicinal preparations, especially as an anti-diarrhea agent.