Tannin Additions?

So, I've had a cider aging since early February in a carboy. I'm wanting to bottle soon, but when I sampled it today it tasted a little thin. On a recent trip to the LHBS I saw powdered tannin, which should help add body. Is it too late to add before bottling? I plan on sweetening before bottling, could I add it then? If so, I have a 6gal batch, what is a reasonable amount of tannin per gallon? Thanks!

Tannin won't add body, it'll add astringency/bitterness and maybe some mouthfeel that adds to the complexity of the cider, but it will still be thin. The best time to add tannin is before aging (primary ferment is good too) so it can do it's thing and drop out with the sediment.

Sweetening alone should help bring back some of the apple flavor, but sweetening with concentrate will boost flavor even more and add some body.

Then if you plan on carbonating it that will add some to the cider too.

What was the original recipe, straight juice, or did you add any additional sugar/concentrate?

This was actually my take on a blueberry cider. I added craisins, steeped 4 tea bags, 1.5lbs brown sugar, and blueberries. I had planned on backsweetening, it just felt thin(?) in my mouth and a bit watery when I sampled it. I know what all I put in to try to avoid that, so maybe I'm being a little paranoid?