GFI trips the GFI, but works fine on a NON GFI circuit, only problem is the long cord (25 ft)

Hello Joesal,
A GFI receptacle senses and imbalance between the hot ( line voltage) feed and ground. There should be no current sensed on the ground. This protection feature will disable the line voltage in milliseconds if it sense current passing thru to ground. The intent is to sense current flow to ground and in the event that you are that path ( meaning current is flowing thru you as a ground)..it disables that line voltage in milliseconds to keep you from being electrocuted. You have either a bad GFI receptacle or there is leakage current getting thru to ground. In either case, its a good idea to determine which is the problem.. I suggest you try your coffee maker on another GFI receptacle in your home ( perhaps in the bathroom or basement) to verify the coffee maker isn't malfunctioning. If it is,, then you may want to discard it or if you are elecrically handy, repair it,... Do not compromise you or your familys safety with these things.. Be careful and good luck..
In addition,if you do run the coffee maker off an extension cord, make sure it is properly sized for the current that your coffee maker requires.. I wouldn't use any extension cord less than 14 gauge ( #14 )
Good Luck..