In one of the buckets, mix together the coffee & water. Cover & let sit for 24 hours. Set up a cheesecloth lined sieve on top of the additional bucket. Pour through the sieve into the other bucket. Strain a second time if you would like. Store in a beverage dispenser or a couple of 1-gallon pitchers in the refrigerator.

Mix in milk & sweetened condensed milk (or whatever additions of your choice) and combine well. Taste, and adjust to your tastes if you need to.