Last year as I was tasting loquats on trees around town (probably all seedling ornamentals) to see if any were worth propagating for fruit I noticed that on at least some trees fruit that was fully yellow sometimes was just so-so but when revisited a week or two later and with a faint hint of orange in their color were much sweeter and more flavorful.

Yeah, I do tend to sample things on the early side. Guess that's why I like many of the sub-acid stone fruits. :)

I know these were plenty ripe as the seeds had started to split a little. I am very pleased with the Champagne loquat's citrus flavor tones: