Sorbet is a dessert with only one secret, and that secret is a ratio - not a machine. The rule goes: three parts fruit to one part sugar syrup. That is the proportion that makes homemade sorbet come out creamy, keeps it from crystallising and preserves the taste of the fruit. Everything else is technique you learn in ten minutes.

First, the distinction most people mix up. Sorbet contains neither eggs nor dairy, and its texture is closer to ice cream - just less creamy, with a light crystalline quality. Granita is something else: water, juice and fruit are mixed with crushed ice and the texture stays grainy. Both are refreshing, but they are not the same dish.

Without an ice cream machine - the tray method

Make a syrup from water and sugar and leave it to cool. The fruit is pureed, strained or passed through a fine sieve, depending on how smooth you want it. Combine it with the syrup and check the consistency. Then air is worked in with a blender - that step is the difference between sorbet and a frozen mush.

The mixture goes into a freezer at at least minus twenty degrees for four hours, but every thirty minutes it comes out and gets blended again to break up the crystals. That is the whole job. Finished sorbet keeps for fifteen to twenty days at most - after that the texture starts to give way.

The fifteen-minute version

If you have no time, there is a simpler route: blend fruit that was frozen beforehand - berries, mango, pineapple, watermelon, peach - with cold syrup, water or juice. The creamy texture comes immediately, no machine and no waiting. This is the recipe worth knowing in August, when a watermelon from the market costs less than any tub of industrial ice cream.

The homemade version has another advantage that rarely gets mentioned: you decide how much sugar goes in, and there is not a single additive or preservative. Among the nine combinations worth making - lemon, lime with mint, mango with a raspberry and basil coulis, peach, avocado with lime, passion fruit - the fastest are done in five to fifteen minutes.

You do not need a three-hundred-euro appliance to make a dessert that costs about as much as a kilo of fruit. That is the entire discovery.