Use this yeast starter when making Gabriele Riva's panettone recipe.
- 2 cups peeled, cored, pureed, and drained Granny Smith apple
- 4 cups high-gluten flour, plus more as needed
- 2 cups sparkling water
- Flat water, as needed
In a large bowl, mix together apple, flour, and sparkling water until well combined. Cover with plastic wrap and let stand in a warm place for 48 hours.
Weigh dough and discard 2/3 of the dough. Return remaining 1/3 of dough to large bowl; add an equal amount of flour and half of the dough's weight in flat water. Mix to combine. Cover with plastic wrap and let stand 4 hours.
Weigh dough again and return to bowl. Add an equal amount of flour and half of the dough's weight in flat water; mix to combine. Repeat process every four hours until the mixture is able to triple in volume in only 4 hours. This will take at least one month.