Mix eggs and broken shells with coffee. Add 2 c. water. Divide in two equal parts; place each part in a cheesecloth bag and tie securely. Allow space for the coffee to swell.
Measure 9 qts. water into each of two large coffeepots or kettles. Immerse a cheesecloth bag of coffee in water in each container. Bring to a boil. Stir and then remove from heat.