Jam storage

[Bonnox]

Hi all just thought I'd share this, some of you seasoned pro's will probably know this but for noobs like me I found it quite interesting,
Went to a festival this weekend and was talking to a woman who has been making her own jams for the last 40 years, she was doing a demo on how to make jam with only 3 ingredients fruit sugar and lemon juice, but what I found really interesting is that she is eating jam now that she made 15 years ago ! When made this way and stored correctly it will last at least that long, I did try some of her 15 year old jam and to be honest it was lovely tasted like fresh from the shop, I got the recipes form her so if anyone is interested let me know, she also makes marmalades and mustards