01 - Rinse cranberries thoroughly and discard any soft or spoiled berries.
02 - In a medium saucepan, mix cranberries, orange zest, orange juice, sugar, and water.
03 - Heat mixture over medium-high heat until boiling, stirring occasionally.
04 - Reduce heat to medium-low and simmer for 10 to 12 minutes, stirring occasionally until cranberries burst and sauce thickens.
05 - Stir in cinnamon and allspice if desired.
06 - Remove from heat and allow to cool to room temperature; sauce will thicken further as it cools.
07 - Transfer to a serving bowl or airtight container and refrigerate until ready to serve.