Adding extra gravity to a wine kit

Hey everyone.

So last year I made a Chateauneuf du pape (sp) and took some off and made port with some brandy and left over concentrate. It was phenomenal. But I only made a gallon and it went in a hurry. So a buddy of mine and myself wanted to make 6 gals. It was a 10L kit (for 6gal).

I didn't pay enough attention when the LHBS owner went and grabbed the kit, it had the same name on it, so I bought it. after I got home and started in, I realized it is not the same kit. It is only a 9L kit, meaning I am not going to end up having the same gravity and body I had when I did it last time.

So, what I want to know, is there anyway to supplement the gravity/body (fermentables, as I will be adding brandy later anyways) on the wine without effecting the flavor? I doubt I can just add welches grape concentrate and not expect it to mess with it much. But can I do what I do with my beers, and add inverted sugar in with a bit of water? Since the yeast take it to terminal gravity I shouldn't have to worry about the wine "thinning" right? Just looking for suggestions. Or is there a place where we can buy "wine juice concentrate" without buying a whole kit?

Thanks and I look forward to your comments.

Kyle

I buy varietal wine concentrate in a can (making my first batch of Barbera) from NortherBrewer, that might be a possibility. It comes in a 68 brix concentration, my Barbera was $15 I think, so alot cheaper than a kit. I'm not sure if you want to add sugar to boost the body, some people might suggest bananas or raisins (I've only seen that in non-grape wine). Or just make a smaller batch and dilute it less?

That is actually what I was hoping to find. I checked some places but not northern brewer. Thanks!