After bottling the umeshu, we always have to decide what to do with the remaining plums. My wife aksed me to share this story. When we first started making umeshu, my mother suggested that we take the plums used to make plum wine, bake them in a “musui-nabe” 無水鍋, which is a Japanese invention, somewhat like a cast iron Dutch oven, for several hours to make them soft and then eat them as a kind-of jam. Following her advice but since we do not have a “musui-nabe”, we put the alchohol soaked plums left over from making umeshu into a pyrex baking dish, covered the baking dish with a glass lid and put it into a 350 degree oven to bake for several hours.
I store this in a glass container with a tight lid in a refrigerator. As long as you use a simple syrup (very sweet), this will keep a long time. Actually, this one is two years old. Other usages of the Umeshu plums is to make it into jam. I see that you can use the Umeshu plums in stewing meat such as pork or chikcen, which I have not tried.