In a small bowl, dissolve yeast in water. Let stand 10 minutes.
In a 2-quart glass, plastic or ceramic container, combine 1 cup flour and 1 cup sugar. Mix thoroughly with a whisk or fork.
Slowly stir in 1 cup milk and dissolved yeast mixture.
Cover loosely and let stand at room temperature until bubbly. Consider this Day 1 of the 10-day cycle. For the next 10 days, handle starter according to the instructions for Amish Friendship Bread.
The starter should be left at room temperature. Drape loosely with dish towel or plastic wrap. Do not use metal utensils or bowls. If using a sealed Ziploc bag, be sure to let the air out if the bag gets too puffy.
Also, when you make a starter from scratch, you can sometimes end up with a much greater yield than 4 cups depending on the temperature of your kitchen and eagerness of your starter. If this happens, reserve one cup for baking and divide the remaining batter into Ziploc baggies of 1 cup each to freeze or share with friends.
For instructions on how to care for your Amish Friendship Bread starter for ten days, read below:
Day 1: Do nothing.
Day 2: Mash the bag.
Day 3: Mash the bag.
Day 4: Mash the bag.
Day 5: Mash the bag.
Day 6: Add to the bag: 1 cup flour, 1 cup sugar, 1 cup milk. Mash the bag.
Day 7: Mash the bag.
Day 8: Mash the bag.
Day 9: Mash the bag.
Day 10: Follow the directions below:
1. Pour the entire bag into a nonmetal bowl.
2. Add 1½ cup flour, 1½ cup sugar, 1½ cup milk.
3. Measure out equal portions of 1 cup each into 1-gallon Ziploc bags. Most people will end up with 4-7 portions depending on how active your starter has been, especially if you made your starter from scratch.
4. Keep one of the bags for yourself (or leave it in the mixing bowl if you plan to bake right away), and give the other bags to friends along with the recipe.