Help with Fredonia juice wine from Walker's Juice

So I have made several Wine Expert kits and they have turned out very well. Last February we went and visited my parents in Kansas and visited some wineries. The ones we visited had a table wine made from Fredonia grapes that I really liked. I then searched where I could find this juice to make my own wine and found a neat place that sells many varieties of grape juice, Walker's Wine Juice.

I made the wine following the Wine Expert kit instructions for adding finings on 03/25/15. I added the same amount of Betonite and used WLP 740 yeast. I racked to a secondary on 04/16/15. I degassed on 05/18/15 and added metabisulphite and sorbate, the same quantities as in the wine expert kit and added chinosan.

I went to bottle it today, but when I tasted it, it was very tart. It had the aroma, I expected, but the taste was way too tart.

Can anybody advise where I screwed up and if I can add anything to save this batch? In the future is there anything better I should do? I think Walker's is great, I just think my process was messed up.

Thanks!!!

Without knowing the steps that you followed to make the wine, I can only comment on a few things.
Cold climate grapes such as Fredonia, tend to produce crisper, tart fruit, this may be the case with the juice that you purchased.
What was the starting and finished Brix or SG?
I do not have any experience with the yeast that you selected, nor do I know anyone that has ever used it.
The wine is very young, it needs to age a minimum of 6-12 months, this will help it mellow a bit.
Keep in mind, the natural sugars in the grapes that you start out with is used by the yeast to produce the alcohol.
Kits are balanced by the manufacturer, following kit instructions for a fresh grape wine won't give you the desired results, but, seeing that you added sorbate, you can back sweeten the wine, just enough to balance out the tart taste.
I'd let time do the degassing and clarifying, it will happen naturally.

So to sum it up, I'd let the wine age longer then back sweeten before bottling.

I hope that this helped

Thank you for your reply. Unfortunately, several months ago I spilled water on my note sheet and lost my info. I will take your advice and try back sweetening and age it longer. Tyen do more thorough research using that juice again. The wine has a great aroma, so I have hope.