Thank you for the suggestion Bryan. Following that strategy, how dry were you able to ferment a dessert wine kit? And did you end up using the entire chaptalization pack?
It was dry -- although 0.998 seems a bit high for a near 18% ABV wine, it was heavy even before the F-pack, so I attribute the FG to that. SG is commonly treated as all sugar, but the alcohol and non-water components of the must and later the wine all contribute to the SG. I used the entire F-pack -- a fruit and chocolate flavored port will be sweet. I bottle in splits, as it makes the batch go farther, and I rarely want that much in one sitting.
Since yours didn't ferment out dry, it makes sense that the final result was too sweet for your taste.
IMO, if a kit is properly created, the F-pack should balance with the acid level of the wine. The resulting wine may be perceived as more or less sweet, but it should balance.
I made FWK Frutta Blackberry and Strawberry, and each took 2 conditioner packs, a lot of sugar. The wines are acidic enough that they needed that much sugar to balance. Oddly enough, while both are certainly sweet wines, the perception is semi-sweet. I have a few bottles of a commercial Vignoles that is labeled sweet, but the perception is off-dry, as are a few premium Vouvray in the rack.
Fork who prefer a sweeter wine might add more sugar to the Frutta. I'm happy with them as-is, but folks can customize to their likes.
I've got a "Port" melding now. I took 6 bottles of last year's wine (barrel aged), fortified to 20% ABV, and added sugar. My son & I disagreed if the wine needed more sugar, so it's melding for a few weeks. We'll taste it again before Christmas.
You may find that commercial "Port" kits don't work for your taste. Do what I did -- take a year old wine (I blended 2), fortify (I used EverClear 151), and backsweeten to taste. If the wine tastes a bit flabby add a
tiny bit of tartaric acid to perk it. If you want flavoring, you can purchase flavorings (LP sells them), and tweak it to your own desire.
Another thought, regarding the base wine -- ferment dry then split the batch. Fill a 3 gallon carboy with half (to be bottled as a table wine), and step feed the other half as far as you can. Once you get to ~15% ABV, make a overnight starter with EC-1118 and continue feeding. Once the wine is clear, top with a red and bulk age for a year.