Hi all. I brewed my first beer back in March (a stout) and bottled it towards the end of the month. I let it age for a good 6 weeks before trying it (more self-control than I'd ever displayed in my life previously!) and when I first cracked it open it was pretty tasty. Another few weeks on and it was even better. For various reasons I had about 15 bottles left that I've not got around to now. One or two that I've cracked open recently have an ever so slightly sour taste to them. Is this possibly due to how long they've 'aged' for or is it just one or two bottles that are 'off'? The various bottles have been of varying quality due to a complete lack of precision when adding sugar for priming.