Pour half the water in two half-gallon pitchers. Sprinkle 4 ounces ground coffee over the water in both pitchers. Cover and let sit 30 minutes; after 30 minutes, stir.
4 quarts filtered water, 8 ounces dark roast coffee grounds
Cover again and let sit at room temperature overnight.
Line a fine mesh strainer with a double layer of fine cheesecloth or a coffee filter set over a large bowl or pitcher. Pour the coffee mixture through the strainer and allow the liquid to run through. The coffee mixture will take several minutes to strain, and will need to be done about 2 cups at a time. When finished, discard the coffee grounds.
Pour the strained coffee in a covered container in the fridge until cooled.
For the Homemade Sweetened Creamer
In a pitcher or bowl whisk together the heavy cream and sweetened condensed milk. Store in the fridge in an airtight container until ready for use.
½ cup heavy cream, ½ cup sweetened condensed milk
For Assembly
Fill a glass with ice (or better yet, coffee ice!). Pour ¾ full with coffee. Fill the remaining ¼ with the creamer mixture. If you prefer a sweeter and creamier iced coffee you can do equal parts instead.