- Place coffee into 4-cup container. Add enough water to measure 4 cups, then let coffee steep 8 hours. Pour through fine-mesh strainer. Repeat straining until all coffee grounds are removed. Reserve.
- Pour sugar into gallon container. Add enough water to measure 1 gallon and stir 5 minutes. Let mixture rest 15 minutes or until sugar dissolves and syrup is formed. Stir 5 more minutes if necessary.
- Pour coffee into gallon-size container. Fill with enough syrup to measure 1 gallon. Store in refrigerator until ready to use.
- Fill 12-ounce glass with shaved ice, then add 8 ounces coffee syrup. Serve immediately.
To make café au lait syrup, combine 14 ounces sweetened condensed milk with 18 ounces coffee syrup.