I'm interested in brewing kind of a coffee wine. Would it taste at all like Kahlua? I imagine the coffee flavor would be slightly weaker. Recipes for it I've seen have described the taste as "unique" but nothing very informative.
This is the recipe I use to make Kahlua.
1 qt water
Bring water, sugar, and coffee to a boil in a saucepan. Simmer VERY slowly for 3 hours. Mixture will be very dark and syrupy. Cool. Add vanilla and vodka. Makes 7 cups.
Instead of using instant coffee, make a 1 quart batch of coffee to whatever strength you prefer, then use that as a replacement for the 1 qt of water and 3 tablespoons of instant coffee.
As you probably noticed there is no brewing involved, except for making some coffee. The alcohol comes from the vodka and sweet taste comes from the 2 and half cups of sugar. Effectively, Kahlua is just coffee flavored syrup with some vodka (or other source of alcohol).
It would be possible to follow a process similar to making Port, where you ferment a must (brewed coffee and some source of sugar), allow the fermentation to proceed, stop the fermentation process at some point, then add some source of sugar back to provide some additional sweetness. However, the end result would probably be nothing like Kahlua, though it might make an interesting experiment.
I have made coffee wine before and it was the biggest pain of all the wines I made, it never stopped foaming! Maybe I did something wrong.
As for the taste, wine never really tastes like what it is made from. You would have to add flavor after it is done brewing and before you bottle it. For example, I make a great strawberry wine and it smells so nice but, it doesn't taste like a strawberry. It has about the same amount of strawberry flavor as putting a whole strawberry in a class of water and then drinking it. You may smell it a little and even fool your taste buds into thinking you taste strawberries but, it is very faint. I mean, yes, you can taste it, but it isn't strawberry juice.
Kahlua professes to be a coffee liqueur, so I'd imagine anything made with coffee will kind of taste like Kahlua, but you're going to need to be more specific about your plans for us to give you a good answer.
Sweetened coffee can be combined with coffee-steeped grain spirits to produce a homemade coffee liqueur. I've done it; use decent coffee, throw in a splash of vanilla and a cinnamon stick, and it's tastier than regular Kahlua.
The advice I'd have for a coffee wine would be to start with cold-brewed coffee, to reduce the "stale coffee" flavor you might get from letting hot-brewed coffee sit for a long time.