Cascading Kitchen Notes
Old farm yards were famous for having apple trees in their yards that were so bitter they were inedible. But they weren't supposed to be eating apples. They provided the pectin required for making jam or jelly. Otherwise you just had syrup. Hard green, sour apples have high amounts of pectin that can easily be cooked and stored in jars.
This is a link to curriculum Terrie developed over years of teaching canning and wisdom gleaned from older friends over many years. The hard green apples available from Jubilee will make great pectin for your jam and jelly making.