Preheat oven to 100ºC
Wash the jars with hot soapy water and sterilise in the oven for 30 minutes
Boil one litre of water and set aside to cool.
Once sterilized, cool the jars to the touch.
Now add the apple scraps, adding any smaller bits like peels first. Then add the cores. Pack it all in the jar as tightly as possible so that nothing floats up.
Add the sugar.
Pour in the water. At this point, if any bits are floating, remove them.
Press down the smaller jar, or pickling weights if you have them, on top of the apple scraps to ensure nothing is floating, and everything is submerged. If scraps are floating, remove them. Otherwise, they will get mouldy and spoil the vinegar.
Cover with the muslin cloth and use a rubber band or string to keep it in place.
Set aside the jar in a cool, dry, dark place for three weeks.
After three weeks, remove/strain the apple scraps and transfer the vinegar into a sterilised glass bottle and cover with a muslin cloth, secure with a string or rubber band.
Set aside for another three weeks.
After three weeks, check the vinegar and taste. It should be ready to use.
Remove the muslin cloth and secure the lid.
With time, the vinegar will mature, and the colour and flavour will change.