Don't call it ice cream.
Not if you're in Milwaukee. Not if you don't want to be ridiculed as rude, clueless, a rube.
Folks in Wisconsin's largest city take their signature dish seriously -- no offense, cheese curds -- and consider it an insult to confuse their rich dairy dessert with ordinary supermarket ice cream.
You'll find frozen custard stands scattered across the Milwaukee metro area. So many that tourism bureau Visit Milwaukee claims it's home to the world's largest concentration, making Milwaukee the unofficial "Frozen Custard Capital of the World."
But ask 10 natives to name the best spots and you can expect to get 10 different answers.
To find your own favorite, you could set out with a short list from Visit Milwaukee or book a tour with Milwaukee Food & City Tours and get a sprinkling of frozen custard history and anecdotes as you ride a bus between tastings on a Sunday afternoon.
Tour guide Caitlin Weitzel gave us the scoop on frozen custard vs. ice cream. Both are made with milk, cream and sugar, but frozen custard adds egg yolk. The Food and Drug Administration weighs in with a regulation: Frozen custard must contain 1.4% egg yolk solids and at least 10% butterfat.
Another difference comes down to something called overrun, the air that gets pumped into the creamy concoction in the production process. A dish of soft-serve ice cream might have an overrun of 100 percent, meaning it's half air. Frozen custard averages 15 to 30%.
The quick freeze machine that makes the stuff -- so massive it's nicknamed an "iron lung" -- churns out thick, delicious swirls about 8 degrees warmer than ice cream. Grab a cupful or cone and eat up. See if you don't agree that it's denser, richer, smoother and has a silkier texture than ice cream.
Despite its local fame, frozen custard did not originate in Milwaukee. Weitzel said recipes calling for egg yolks in ice cream date to 17th-century France, and Thomas Jefferson is responsible for the first recorded recipe in the U.S.