In the 1st Century AD the first known cook book De Re Coquinaria (the art of cooking) contained the first recipe for Jam. Large scale jam production wasn't possible until around 1785 AD when Nicholas Appert worked out that boiling jam and storing it in airtight jars would prolong the life of it significantly, This process is known as pasteurisation. This is a process still in use today. In my childhood my Grandma would pick fruit from the orchard and produce up to 150 jars of jam a year ranging from apple and blackcurrant jelly to gooseberry jam and my they were good. She was a hardworking farmers wife and was and still is a blooming good cook.
At Rainbowvapes we created one of the first jam on toast e-liquids, upon vaping the first prototype we were shocked with the way the sweetness of the strawberry jam came across with the slightly overdone toast behind it. Many eliquid brands have replicated the same taste too. If toast isn't your thing then there are other jam inspired vapes with gingerbread, waffle or cake tones too.