Experimenting with starter

I made a starter with a little fresh pinneapple juice before, just to get it going in the beginning. This works quite well. Now i started a new one and wanted to try adding something else, didn't have much at home, so i went for 5ml of Umeshu (Japanese plum wine) in 100gr flour and 95ml water. After my first feeding 12h later, it has doubled in size. I know the natural sugars can give it a boost, but what about the alcohol in the wine? Whats that doing to the starter? Because it seems extreemly potent at this early stage, i wonder if the alcohol is part of the reason.