[JohnnyC]

Do I need to obsessively clean a keg that contained a kettle soured beer that was fermented using US05? i.e. replace all the gaskets?

[erockrph]

Did you boil after the kettle souring, or just run off and pitch? If you boiled, then there is no lacto that survived in the finished beer and there is zero cause for concern. Even if you didn't boil and there was live lactobacillus in the finished beer, I would just treat it as usual myself. Lactobacillus should be eradicated quite simply using your normal clean and sanitize routine.

The only exception is if you innoculated the kettle sour with grain rather than a pure culture, and didn't boil after the souring period. At that point you have no clue what bugs made it into your keg. I'd treat it like a Brett beer at that point, just out of precaution.

[kramerog]

I don't change gaskets for cornies just because I'm changing from a sour to a non-sour.  I do however take apart kegs between batches normally for cleaning and sanitizing.