Wash the quinces and scrub them thoroughly. Cut them into rough pieces (no need to peel or remove the core) and place them in a pot. Pour lemon juice and water over the quince pieces until they're covered, and bring the pot to a boil. I use approximately 1 liter of water for 1 kg of quinces.
1 kg quinces, 1 liter water, 2 lemons
Let the quinces simmer for an hour with the lid on until they are completely tender.
Strain the juice. Use a jelly stand or a strainer with a clean cloth. Let the juice drip for a few hours until all the juice has drained. Measure the juice after that and transfer it to a clean pot.
Add sugar to the juice. You should use 750 grams of sugar per liter of juice. I got 1 liter of juice from this batch. Bring the juice to a boil with the sugar. Let it simmer for about 25-30 minutes until it thickens and turns a beautiful red color.
750 grams sugar
Take a spoonful and place it on a cold plate, then put it in the refrigerator. Check if the jelly sets within a couple of minutes in the fridge; if it doesn't, it needs to be cooked a little longer.
Remove any foam from the top of the jelly with a spoon and pour the finished jelly into clean, sterilized jars, which can be rinsed with alcohol for extended shelf life.
Allow the jelly to cool completely before sealing the jars to ensure the jelly sets properly.