How to Make Acorn Flour. Step 1: Collecting Acorns. Step 2: Separating Acorn Caps from Nuts. Step 3: Drying Acorns and Nuts. Step 4: Sizing, Sorting, and Shelling Acorns and Nuts. Step 5: Debittering Acorns. Step 6: Following Acorn Food Safety, Optional Drying and Pulverizing. Step 7: Creating a Value-Added Acorn Product.