Low alcohol content and vinegar

Hello,
I just finished the first racking of my wine. Back in the beginning when I was trying to get the specific gravity up, I was adding so much sugar that I began to think I was going to ruin something, so I backed off. I think my alcohol content has ended up to be something like 10%, which I was fine with. Now I have read that it's not good to have wine under 12% alcohol, because it won't keep very long once it's bottled.
Is this a problem, and if so, can I do another fermentation to raise the alcohol content?
Secondly, the wine from one of my carboys smelled a bit of vinegar. I'm not sure if it was enough to be alarmed, but it was definitely there, especially in comparison to the other carboy. Is there a way to remove the vinegar at this point if it is too much?
Still learning...and thank you all for your help!

Starbuck

Wow- so many questions! I'm glad to try to answer some of the ones that I can.

First, what yeast did you use and what was your og and how to you get to the determination that you're at 10% ABV? Next, vinegar is caused by acetero bacteri contamination and is not salvageable if it's truly contaminated. I'd try one campden tablet per gallon (crushed and dissolved) in it and see if that stops it. Stir gently, as to not aerate.

Did you use any campden at all? What was your recipe? You can still boost the sg and ABV if you wish to raise the ABV, but I'd wait for a little bit just to make sure it's not contaminated first, and make sure your yeast can handle it.

Thanks for the help, Yooperbrew.
I used a red wine yeast, but now I can't remember the specific name of it. (Bought it at the homebrew store.) As far as ABV, I made a rough guess after watching the SG drop and realizing it had not started out high enough to make much alcohol (first reading was 1.060). So I went through a second adding of sugar, let it drop again, and added those two numbers together. Unfortunately, I didn't get my SG reading immediately after the second sugar addition, which is where the guessing part comes in.
I have not used any Campden tablets, but I have used potassium metabisulfite. I just added a quarter teaspoon to each 5-gallon carboy on this racking. (That is also the ratio I used when I added it during the first fermentation.) I don't really have a recipe; I am just winging it, following directions and measurements on the materials I've purchased. The grapes are from my own yard, so there is no kit or anything.
Is it possible to add Campden tablets even though I've already added potassium metabisulfite?
Is there a way to tell if it is contaminated, or whether it's an acceptable amount of vinegary aroma, other than just knowing by smell where to draw the line?
I know it's a lot of info and questions--I really appreciate your help!

S

Well, the potassium metabisulfite and campden are the same thing. As long as you used the sulfite, you might be ok. Did you remember how much sugar you added the second time (and what size batch is it?!!). I might be able to calculate the probably og and from there can give you a better idea of what to do next.

As far as the vinegar-y smell, it might be contaminated. Or it might be just a sour smell. Taste it and see- if it's vinegar, you made wine vinegar. If it's just tart and maybe a little sour, it might be ok.

Hi Yooper,
The second adding of sugar was 4 cups, just granulated sugar boiled into a syrup and then cooled. The batch started out in its first fermentation, when I was adding the sugar, at 20 gallons (then pressed into 13 gallons, and after racking off the first sediment, is 10 gallons).
I will give it a taste and see what happens. I ended up adding the 3-gallon carboy to the two 5-gallon ones during racking, to make up for the lost volume in sediment. Then I topped them both off with a commercial wine, so the whole concoction might taste different now.
Thanks again.

Ok, that's about 2 pounds sugar and it 13 gallons (which what I think you said you put it in), that would only bring the sg up to around 1.067.

Does it taste like vinegar? Or is that gone now? Before you add any more sugar, it'd probably be best to make sure the vinegar-y smell is gone and it's not contaminated. If it IS contaminated with aceterobacter, you'll know pretty soon.

Well, it was 1.060 to start, before adding any sugar. I added three cups the first time around, then 5 days later added the 4 cups I mentioned in the post. Given the 1.067 figure you calculated, that would still sound like around 9% total alcohol content, right?
I haven't opened the carboys up since racking to smell or taste again yet. Now I am all worried about contaminating the stuff every time I open it! Mostly though, since I topped them off with commercial wine which looked to float at the top at first, I thought maybe if it settled and had more of a consistent color throughout, it would be all blended together and give me a better idea of what the batch tastes like. But like I said, I'm new, and that might be a complete misconception.
Say I open them and don't really notice vinegar in a bad way, I am guessing it's okay to do the yeast/sugar fermentation stage again to bring the alcohol level up?
Thanks!

Well, I'm not quite clear on what og to start with, since I thought I had it figured out and maybe I don't! But, you might have had, say, 1.072 or so. That would give you approx 11% abv, which isn't too bad. If you really want to bring it up to around 12%, you can. But it really would be a guessing game since we don't know what you started with. I think I would just leave it alone for a while, to make sure it isn't contaminated with the aceterobacter. Sometimes the most important things with wine aren't the ABV, but the balance, flavor, mouthfeel, acids, etc all play a role. Also, since you're not opposed to sulfite, the wine should keep ok at a slightly lower ABV. I mean, you probably can't age it 5 years, but I don't know if you were planning to anyway.

It might taste better slightly lower anyway. I have found that some wines, particularly some grapes and apple wines, taste better at a slightly lower ABV. Whatever you decide, keep us posted!

Thanks so much, and I will keep you posted! You've been a great help in my new endeavor.

Starbuck