A syrup is simply water and sugar, brought to a boil to mix them well, and then left to cool before use.
The difference is in the ratio of water to sugar, or in other words, how much sugar do you put in how much water?
Of course, starting with 1 liter of water, all weights of sugar are possible, but there are still 2 main proportions very used.
The heavy syrup
It is a ratio of half and half, 1 liter of water + 1 kilo of sugar. The syrup obtained, quite thick, is called "syrup at 30" by pastry chefs.
It is used as a base for fruit sorbets, to soak babas or cookies, or to shine the top of a pastry or pastry.
The light syrup
It is a different ratio, 1 liter of water + 500 gr of sugar. The syrup obtained, quite light, is called "syrup for 60" or "poaching syrup" by pastry chefs.
It is used to poach fruits.
How to make it?
It's very simple, you mix sugar and water in the desired proportions in a saucepan, you bring it to boil for 1 minute, you let it cool and it's ready.
Syrups can be kept in a closed container in the fridge, away from the air. They can also be easily frozen.
The degree of a syrup
As indicated above, the names sometimes refer to a degree, for example 30° for "syrup at 30", it is not a temperature, but an old measure of concentration, the Baumé degree (of the French chemist
Antoine Baumé), which is obsolete but whose use, very approximate, still persists.
In summary: A syrup is a mixture of water and sugar in variable proportions, the 2 most used proportions are 1 liter of water for 1 kg of sugar (heavy syrup) or 1 liter of water for 500 gr of sugar (light syrup).