A Wisconsin cheese maker sold cheddar that is more than 20 years old for a hefty price at a store in downtown Milwaukee. The cheese was for sale Saturday at Wisconsin Cheese Mart. The rare, super-aged cheddar, ranging in age from 20 to 40 years old, was discovered this spring at Zahn Cheese in Oconto as founder Ed Zahn, 73, prepared to retire. The cheese sold from $60 to $96 a pound. Cheese Mart owner Ken McNulty called the quality of the Zahn’s cheddar after all these years a testament to the cheese maker’s skill and the superior milk he used.