I made my first batch of wine (ever) using Concord grapes grown in my
yard. I'm sure I made a bunch of mistakes. I think the main
problems are that I probably didn't measure the TA correctly at the
beginning of the process. Also, I didn't add additional sulfite at
end of primary fermentation.

It's been about 8 months, and I just pulled out some of the wine to
try to retest the TA. Based on today's test it should TA of .973.
(As best as I can tell, I'm never sure if I'm getting the reading
right, because seeing the color change seems so subjective). I also
tasted the wine. It smelled reasonable, tasted a bit acidic and a bit
bitter. The body is also a bit thin, probably because I added some
water at beginning of secondary fermentation. (Another mistake).

So I'm wondering if I can try to fix this up. I have some malolactic
culture that I got for another batch of wine I was making with Syrah
grapes from Chile. (These grapes were very low in acid -- I had to
add acid blend --so it seems they don't need the Malolactic
fermenation?)

Is it possible, and would it make any improvement to add the
malolactic culture to the Concord grapes even though it's so late in
the game? (And on the other hand, would you add malolactic culture to
wine that started out with low acidity.)

Any advice is appreciated...

Thanks.