What is your source for the TDS in Seattle water?
The city regularly publishes tests breaking it all down:
http://www.seattle.gov/utilities/your-services/water/water-q...
Is it really possible that lower TDS makes better water and better water makes better beer and coffee?
I guess that could make it a double-blind test.
I wonder how significant the number of participants is over what length of time and how it compares to the numbers and species in the laboratory rodent work.