In a small bowl, combine the warm water with the dry active yeast. Set aside until bubbly, 5-10 minutes.
In a large non-metal bowl mix together the all-purpose flour and the granulated sugar. Stir in the milk and the yeast mixture.
Cover loosely and leave on the countertop at room temperature until bubbly.
Place starter in a large (gallon size) Ziploc bag. Seal bag and squish, squash, and mush until well combined. Let stand at room temperature overnight. The day that you prepare the starter is DAY 1.
Day 2: Squish and mush the bag.
Day 3: Squish and mush the bag.
Day 4: Squish and mush the bag.
Day 5: Squish and mush the bag.
Day 6: Add to the bag – 1 cup of flour, 1 cup of sugar, and 1 cup of milk. Squish and mush the bag.
Day 7: Squish and mush the bag.
Day 8: Squish and mush the bag.
Day 9: Squish and mush the bag.
Day 10: BAKING AND DIVIDING DAY. Pour the entire contents of the starter bag into a non-metal bowl and add 1 ½ cups of flour, 1 ½ cups of sugar, and 1 ½ cups of milk. Measure out 4 separate batches of the starter batter (1 cup each) and place into large gallon-size Ziploc bags. Keep one bag of starter for yourself to continue the process (Day 10 is equal to Day 1) and give the other 3 to friends along with a copy of these instructions. After dividing the starter into separate bags, you should have about 1 cup of the starter batter still left in your large bowl. The starter that remains in the large bowl will be used for baking your Amish Friendship Bread.