I made the CYBI Bam Biere clone in January. I pitched a starter of Bam dregs about 3 days into fermentation. While our methods were different, mine also went sour surprisingly fast (mine never got too sour, however). I have read anecdotal accounts that oxygenated worts will encourage sourness...
I use an immersion chiller (sanitized) - my cooling times are usually around 20 minutes. I am leaning more towards believing the point of infection occurs around bottling time since even with a long primary or secondary (one beer was about 10 weeks before bottling), I had no sign of infection...
So I've just had my 3rd beer in a row show signs of infection after 5-7 weeks of bottle conditioning. In all 3, the change in flavor has been really sudden, like beer drinking fine one day, open another a few days later and it has a distinct brett flavor, reminds me of brett b. Every...