American Wheat very tart taste - need advice

The background:
About 5 weeks ago I brewed a Blackberry American Wheat. I tried a sample of it last night and it tasted sour/tart. It wasn't exactly unpleasant but much more sourness would be.

I looked on the Wyeast website and it give the following description of the yeast. Notice the reference to tart.
"A dry fermenting, true top cropping yeast which produces a dry, slightly tart, crisp beer. Ideal for beers where a low ester profile is desirable."


The details:
It was a pretty typical recipe. I brewed it in the same manner I've brewed all my others which have turned out fine. Off hand I would say I used about 4 lbs of wheat extract and 3 or so lbs of light LME. Nothing crazy used for the hops or grains. After a week of normal fermentation at 65 degrees I racked it to my corny, added 2oz of blackberry extract and let it sit for 4 weeks. I checked it last night and it had a FG of 1.012.


My questions:
1. Why is my beer so sour/tart? Is it because the low fermentation temps, the blackberry extract, a combination of the two, or did I get a wild yeast?
2. Has anyone else experienced this sourness with Wyeast 1010?
3. Is the beer stuck this way or will it mellow out if I age it longer?
4. Once cold and carbonated, will the sourness be less?


My plan right now is to let it sit another couple weeks, carbonate it, and try it then. Any other suggestions?


Thanks for your thought!
-Jeff

(I posted this in another category but didn't get any replies. I think I just posted in the wrong place so I'll give it another try)

"nothing too crazy" is a little vague regarding the hops you used since it could be a major contributor to your tart flavor. How much volume did you boil and what hop variety and schedule did you use?

2.5 gal boil. Same as all my others which have turned out fine (15+ batches).

Hops were: 1 oz of Cascade 60min, and .5 oz Hallertau for 15min.

Assuming the hops were of average alphas, I get 24 IBU. Wheat beers like to be 10-20 IBU so it could be a combination of overhopping, a yeast that advertises "tart/crisp", and a slight bit from the blackberry extract.

Thanks. Anyone else have any other thoughts or experienced something similar?

I would assume it is your extract, since I just made roughly the same beer with the same yeast (wyeast american wheat?), and didn't get any tart flavor to my beer. I actually split my batch, half plain old american wheat, and the other half got 2 oz of blueberry extract. The plain half is just that, plain! It is very light and refreshing, but really no character to it at all, but that was expected. The blueberry is good though!

I think it will mellow over time, and make sure you let it sit in the fridge for at least 3 days or more before you drink them. I made a weiss beer before i really knew what one tasted like, which has a kinda bananna off flavor to the yeast, but after a week in the fridge, that off flavor is starting to mellow, and the beer is becoming really good. Just be patient!

I know that frozen strawberries can make a beer very tart so maybe it was the addition of the fruit that was the issue?

So I've thought it over a bit and had another sample. I was just freaking out a bit.

This is what I'm thinking. When I took my sample from the corny, it sucked lots of the yeast up from the bottom so my little sample was mostly yeast. Normally, the yeast gives the beer a slight tart taste. In my case it gave it a very tart taste because I had so darn much of it.

Does anyone buy that explanation?