strong white flour

I started a new starter about seven days ago, using an 'offhand' method that's always worked reliably for me in the past to produce a starter with the classic yeasty/sour/yummy smell, stable and robust, with good rising characteristics. Now the same method has produced a starter that seems to rise very well and smells great, but more like someone took the top off a Calvados still: lushly, almost 'ether-y' fruity-sweet and clearly kicking out a (probably) flammable mix of ethanol and acetones.