Originally Posted by marubozo
There are two different things that often make beer taste sour. Acetaldehyde, or lactic acid usually introduced by bacteria. But you also say you only fermented for 10 days, left in secondary for ??? days, and bottled just 10 days. So it's still pretty young and the sour flavor may actually just be green beer.
Sour - Acetaldehyde
Symptoms: Tastes of grass or green apples. Strong vinegar or cider-like tastes
Causes: Premature removal from yeast; premature flocculation; to little oxygen for the yeast; bacterial spoilage; oxidation
Fixes: Full fermentation from a good yeast strain, and aeration of the wort will help prevent this.
Sour - Lactic Acid
Symptoms: Sour for sour's sake. It's a clean sour, not smelling like grass or apples. So if it tastes tart, but doesn't smell like grass or apples, it's probably lactic acid. There also might be a slight vinegar smell. Think white vinegar instead of cider vinegar.
Causes: Poor Sanitation; Acid Creating Bacteria; Some yeast strains; Excessive acid rest; Excessive mashing; storage of beer at warm temperature; Scratched fermenters (harder to clean, so more susceptible for Acid creating bacteria)
Fixes: Good Sanitation practices and using a different yeast strain is a good start. Shorter acid rests and mashing for less than two hours will also help.
I guess this is my problem. the beer was in secondary for a month - sorry for not mentioning it in the post....
it was really hot here while it was in secondary...
I get a little bit of a vinegar in overall flavor. but it is enough to be a reason not to offer this beer to anyone...
I hope it will fade out with time.
thanks for the answer anyway!