Oh yea. I am sure I am one of VERY few brewers using real sauergut here in the states. I was speaking purely of commercial.
Perhaps it’s the yeast I use ( 2206) that doesn’t exhibit the grape as I have never tasted it before in any of my beers.
Cheers.
Ethyl heptanoate is responsible for that flavor. It is a metabolized product of precursors in malted barley.
It is unlikely that dilution of your sauergut by addition to wort or beer transforms the normal flavors of lactic acid (and various other compounds) into ethyl heptanoate or any other grape-flavored organic compound.
It is far more likely that the sauergut fermentation creates conditions that results in a greater degree of ethyl heptanoate in the beer.