After having fun with cooking/drying plums last year, I decided to have another go this year. This time I compared two different ways of cooking whole plums: 140F for ~1.5d vs 350F for ~1.5hr.

I was curious whether the higher temperature was better or worse. Maybe interesting flavors are lost with higher temperatures, or maybe they're lost with longer time? Maybe these approaches differ in how they convert starch to sugar?

Here's a picture of the 350F plums as I was removing them from their tray:

After taking them out I manually removed the pits, and I made sure to scrape the pan with a spatula to get the tasty juice.

Here are ready-for-rebagging pictures of both, 350F on the left and 140F on the right:

I did some testing, where people didn't know which was which:

Overall everyone liked the 350F better: richer plum flavor. One taster thought the 140F had a bit of an "off" flavor. The 350F was less sweet, enough so that for many dishes you wouldn't want to use it straight, but adding sugar to taste later isn't hard.

(The 350F is also way easier logistically—tying up the oven for over a day isn't great housemate behavior.)