A weighing instrument is very useful in jam-making. Yet another solution can be applied when the jam is made with fruit puree.
When I make compote and stewed fruit, I hardly ever weigh the sugar. I tend to just add some according to taste.
I am more precise when I make jam. However, today I didn’t have my scales with me.
I couldn’t weigh anything, neither the fruit puree nor the sugar. So I had to be inventive. Here is the solution I found.
How could I add around 800g of sugar per kilo of blackberry puree? I thought I would use the scaled jug I found in the cupboard. I would measure the volume of puree and add the right amount of sugar accordingly.
Fruit puree is not as dense as water, it weighs slightly less. So I thought I would add a little less sugar. I went for 750g per liter of puree.
I jotted down the volumes of puree and added them up at the end. The number of packs of sugar was then calculated: 4.6 liters of blackberry puree x 0.750 kg = 3.45 packs of sugar. I added three and a half, visually estimating the half. Easy!