While reading on Serious Eats I found a link to
this method of removing the membranes from citrus segments using an intense pectinase. If you've ever wondered how they peel those mandarin orange segments in a can -- this is how.
I thought about this, and about my troubles with my fruit ratafias -- after several months, small particles of fruit and dissolved pectin form nasty blobs of gel in the drink which look like mold (even though they aren't) and are total turn-offs. (Amusingly, the quince ratafia doesn't do this because the quince is so firm it just doesn't spall off little strainer-escaping bits to disintegrate and form blobs later on.) I think treating the fruit with pectinase before adding the alcohol should help destroy that lingering pectin and the little pieces made mostly of it.
So, I bought a bottle from Modernist Cuisine's online shop. I'll try it on some blueberries next, to make the Blueberry Basil Lemon suggested to me by
lyonesse, and see how it goes.