Sour beer

Two weeks ago I had a brew day in which we completed two all grain brews; A pale ale and a stout. I gathered grain and hops from various sources and drove off to my not-so-local HBS with assurances that they had a great yeast selection only to discover after over an hour of driving that they only had one vial of the yeast I wanted to use (white labs 007 English ale yeast). I got home and thought quick; I made about a half gallon of wort with a little malt I felt I could spare for the cause, then pitched my yeast into the starter wort around noon the day before brewing. Brew day came; I shook up the now bubbling starter and poured half of it in my pale ale and half of it in my stout. The beer fermented in my basement closet, which stays at about 65 or 70 degrees. Now it is two weeks later and the stout went into bottles the other day and the pale ale got transferred to a secondary for a dry hop treatment. Here’s my issue: I tasted the stout and it tasted tart, almost sour. The roasty flavors covered up most of it but it was still there. The pale ale had the same flavor compounds, but with the absence of roasted barley it tasted tart, kind of like cider. It was my first time using the 007 yeast, and my fist time brewing batches this strong (both weighed in at about 1.070 OG). Have I had my first real infection problem? Has some wild yeast managed its way into my starter, or this normal for this strain of yeast? Is the cidery flavor normally associated with the slightly higher OG? Will this age out or get worse?

It should mellow out overtime. let the stout sit inthe bottles for 3 to 4 weeks before you test one, you should notice a much better beer. same thing happened with me, my wife thought it was the worst beershe ever tasted, now three weeks later she wants me to brew more! so with time the flavors will mesh and mild out. Hey what brew store did you go to? Im in Blowing rock and looking for a closer store then alternative beverages.

I suspect your ales got a bit warm during the ferment. Keeping a high gravity wort cool can be a problem, as the yeast can generate a fair amount of heat. I've had ferments hit 15F above the room temperature.

Fortunately, if that was the only cause of the sour flavor, it should decrease as the ale ages.

Did you boil your 1/2 gallon of wort for the starter? If not, you made a lacto-bacillus starter and a sour-mash beer, or two. Lacto is on everything, and is used for acid preservation, like in Sauerkraut? Sour beers are made that way on purpose, by mashing some malt, and leaving it in the cooler for a day or so. Probably not harmful, good in hot weather?

I boiled my starter wort. I prepared it just like I do my beer, but without hops. Mash, sparge, boil, chill, pitch yeast, shake well, jam an air lock on it (also sanitized) and put it in a dark closet. I am willing to believe that it got too warm during fermentation. No air moves in the closet.