ISO: Concord Grape Coffeecake

I just returned from New York State's Finger Lakes district where roadside stands sell Concord grape pies, and, surprise to me: Concord grape coffeecake. The cake does not include yeast. It is a simple coffeecake with a streusel topping. The ingredients are flour, brown sugar, sour cream, sugar, grapes, butter, nuts, egg, baking soda, salt, tapioca and cinnamon. I bought the cake at the Indian Pines produce stand just outside Penn Yan. The baker is Deb Trishchler of Naples, NY. My question is how she extracts the seeds from the grapes. I'm not optimistic that she will reveal her recipe.