“One day I was eating a bar of Cadbury Dairy Milk and I thought, this has absolutely no flavor,” he said. “I looked at the label and saw it was made by Hershey. I was outraged.”

Cadbury Dairy Milk is the iconic British candy bar, the one most likely to be tucked into the suitcase of a Yankee tourist looking for an inexpensive souvenir. Versions are filled with caramel, whipped fondant, whole nuts or pellets of shortbread cookie.

It’s a different bar from the Cadbury bar available in the United States. According to the label, a British Cadbury Dairy Milk bar contains milk, sugar, cocoa mass, cocoa butter, vegetable fat and emulsifiers. The version made by the Hershey Company, which holds the license from Cadbury-Schweppes to produce the candy in the United States under the British company’s direction, starts its ingredient list with sugar. It lists lactose and the emulsifier soy lecithin, which keeps the cocoa butter from separating from the cocoa. The American product also lists “natural and artificial flavorings.”

Tony Bilsborough, a spokesman for Cadbury-Schweppes in Britain, said his company ships its specially formulated chocolate crumb — a mash of dried milk and chocolate to which cocoa butter will be added later — to Hershey, Pa. What happens next accounts for the differences.

“I imagine it’s down to the final processing and the blending,” he said. After consulting with chocolate manufacturers in each country, Cadbury tries to replicate the taste people grew up with, he said. In the United States, that means a bar that is more akin to a Hershey bar, which to many British palates tastes sour.

Kirk Seville, a spokesman for the Hershey Company, declined to explain the manufacturing process, saying the company preferred not to take part in a discussion about the manufacturing differences between a British and an American Cadbury bar.

Image Casey Acierno shopping at London Food in Montclair, N.J. Credit... Sylwia Kapuscinski for The New York Times

For people here with a taste for British candy, no explanation is necessary. Their opinions are already formed.