One of the problems with drupes (cherries, plums, nectarines, etc) and some other fruits like apples and pineapples is that a lot of the acid that is in them is
malic acid. It's a very strong, very sour tasting acid.
Even using only one 1 litre carton of pineapple juice in a 4.5 litre brew, I found my pineapple liqueur far too sour to drink even when I tried to encourage a malolactic fermentation (MLF) by leaving it on the lees for a few weeks after the primary yeast fermentation has finished. I think this is because of the sterilisation of the carton juice.
Lactic acid is considerably less acidic than the malic acid, less sour tasting and a little bit buttery.
The drawback of the MLF is a loss of fruity fragrance, so perhaps blending could be preferable to MLF at times?
I enjoyed my pineapple liqueur blended (in the glass) with orange liqueur and freshly made banana juice (lethal concoction!). The gum that makes banana a PITA to brew
really smooths it out when it's added
immediately before drinking. It's a faff to make banana juice though! Much nicer if you can just open a bottle and enjoy.
That's one thing I haven't tried, actually making the malolactic fermentation happen by adding some of the
Oenococcus Oeni bacteria when the yeast fermentation has finished.