An earlier batch of Pretender to the Crown picked up a small lacto infection somewhere in the transfer process. The beer went sour — not in a fun, intentional lambic way, but in a "something went wrong" way.
Rather than dump it, the batch was redirected into malt vinegar production. Turns out infected beer makes surprisingly good vinegar.
The infection was traced back to the counterflow chiller — difficult to fully clean and sanitize, with too many places for bacteria to hide. It was replaced with the JaDeD Scylla, a copper immersion chiller that's easier to disassemble, inspect, and sanitize.
No further infections since the switch.
The soured beer was transferred to a vessel with a vinegar mother and allowed to acetify over several weeks. The result: a malt vinegar with a surprising depth of flavor — malty, slightly smoky, with a sharp acidity that works well on fish and chips or as a base for marinades.
See Vinegar & Other Ferments for more on what happens when beer goes wrong at the Manor.