A drop of egg white in a bottle of wine with too much harsh tannin. The egg white will precipitate the tannin. I tried it a few months ago and it does work. Of course you have to rack it again to remove the preciptated tannin.
a commercial $3/bottle of merlot is bulk wine plain and simple, the same wine that many countries overproduce and end up turning into industrial alcohol. where volume is the vineyard's key motivator - very little attention is paid to cluster quality, ripeness, sugar levels, etc, it is about maximizing yield. stressed vines and low yields make the best grapes because everything the vine has left is going into those few grapes - not into foliage and canopy.
personally i don't understand the point of $3 commercial wine. at that pricepoint anyone can make a wine at home that will surpass it in quality.
for myself, i draw the line at about $9 for commercial wine...and that's mostly spain, portugal, argentina, south africa... where bargains can still be found offering good quality at reasonable prices.
while acidity probably plays some role - i think it is contributory. the key fault is that the juice was not good to start with, if you don't start with the best juice, you cannot make the best wine.
My wife and daughter both work at Walmart. They have had a big run lately on $3.00 wine. I've tried a few bottles of it. The biggest thing I see is that is kind of on the weak side.
Color isn't too bad, and it's got alcohol in it, but as far as taste, it's definitely lacking.
I sit back and scratch my head and wonder,if they can sell the wine at $3.00, what are they getting the bottles for, $0.15?