buffering a too tart melomel

I've got a semi-sweet melomel that turned out nice except it's a bit on the tart side. I added some potassium carbonate to remove some acid and the pH went from 3.4 to 3.6.

Although the pH changes immediately, the tartness should remain until the bound acids drop out, right?

Only tartaric acid drops out as crystals. What fruit did you use to make this? WVMJ

I did a 5 gal batch using costco clover honey then added 5 cans of thawed walmart frozen fruit juice concentrate. Did this as an experiment. It too is tart. Any opinions while this poster brought up the topic.

I used a combination of blackberries, raspberries, marionberries, and loganberries. It has a really nice, strong fruit flavor, but it has no residual sugar so that acidity really stands out.

I would put it through MLF to take the edge off, but the wine has been treated with lysozyme to prevent that. So it looks like I'm stuck waiting this one out, if that even works. I have found some evidence to suggest that malic and citric acids will drop out eventually. But even if that's true it takes a lot longer and temperature has no bearing as it does with tartaric.(http://www.101winemaking.com/calcium_carbonate.htm)

"I did a 5 gal batch using costco clover honey then added 5 cans of thawed walmart frozen fruit juice concentrate. Did this as an experiment. It too is tart. Any opinions while this poster brought up the topic."

If you're ok with a sweeter wine, you could back sweeten to balance it out. That's probably the quickest and easiest. If you have time to wait and feel like experimenting, you could inoculate with a maloactic culture or buffer with potassium carbonate. The latter works well if the fruit contains tartaric acid because this acid responds to cold temps. In the fridge or a cold garage, tartaric acid crystals will probably drop out in a few weeks leaving the wine noticeably smoother. If the fruit does not contain tartaric acid, then it probably has malic and citric acids, which will take months to precipitate out and do not respond to cold temps. I've heard 6 months minimum but am not 100% sure.