Hello Colin,
Great to find you in this network.
I have asked a couple wild wine making friends about plums, as we also have wild plums in abundance.
One person said the wine from the plums (and these are the red wild plums with distinctly bitter skins, and juicy sweet flesh) was very bitter after one year, yet much better the next year.
It was similar to the woman who made a mead from them. It seems the bitterness mellows after two years.
Cutting the plums in half, taking out the seed, then scooping out the sweet flesh and composting the skins is a tedious option, yet likely to produce sweeter results.
In the past, I have cut the plums in half, taken out the seeds, pushed the halves forward from the skin side to expose the flesh more (sorta inside out) and dried the half plums. They keep well and the skin seems to mellow and be enjoyable to pack as a trail food.
Please let us know what you decide to do.
Happy harvesting,
Robbie
Morninglory FarmZone 3b* in Ontario