There is a Kum and Go on S Rangeline about 2 miles south of I44 on the right side that has 91 octane with no ethanol.
Old post but was curious about good gas in joplin and thought id bump it. I know the hyvee grocery store gas stations 91 is also corn free but am unaware if there is one in joplin
https://www.pure-gas.org/index.jsp?stateprov=MO Might be out of date but maybe this will help someone.
The Kum and Go 2 miles south of I-44 on Rangeline still has 91 octane with no ethanol. It's not far from the hotel.