to me buttermilk and vinegar are very different aromas.
if you have a lacto infection, it might just add a sourness that is agreeable to the palete.
but if its aceobacter, the batch is ruined unless you can drink it fast enough.
Primary: English Mild
On tap: Pale Ale, Lancelot's Wheat, English Brown Ale, Steam Beer, HoovNuts IPA
Bottled: MOAM, Braggot, Raspberry Melomel, Merlot, Apfelwein, Pyment, Sweet mead, Cabernet
Gal in 2009: 27, Gal in 2010: 34, Gal in 2011: 13, Gal in 2012: 10