if you don't have a big enough pot it would be good to put it on the fire twice, if you make this amount so big: D
Put the lemons and oranges on the small grater and then squeeze well. Grapefruit is squeezed over the peel and the lemon and orange juice. Mix with water and put in a large boiling pot, it is preferable to be a pot because the aluminum pot changes the taste of the jam. Put the sugar and vanilla on top.
Put the pot of syrup on the stove over medium heat, I let it boil for about 2 hours and 30 minutes.
Meanwhile, wash the fruits well and put them on the grater with large mesh or cut them into small cubes and keep 4 quinces.
After the time in which the syrup has boiled has passed, we put the fruit on the grater and the quince stalks over the syrup.
Leave the composition on low heat until the syrup takes on a gelatinous texture, I boiled it for about 5 hours.
Leave to cool and put in jars.
Serve as you like but not in sauces. : D