Why are Ocean Spray’s cranberry sauce labels upside down?

Perhaps one of Thanksgiving’s biggest mysteries is cranberry sauce — and we’re not even talking about why people eat it: What’s with the upside-down labels on Ocean aerosol cans?

Aware consumers have noticed that the Ocean Spray labels on cans of jellied cranberry sauce are flipped, meaning that the rounded edge that’s typically found on the bottom of most cans is on top of Ocean Spray cans of cranberry sauce lies.

According to Ocean Spray, that’s intentional: It creates a seamless serving experience.

The cans are “filled and labeled upside down, with the rounded edge at the top and the sharp can-like edge at the bottom to keep the jelly intact,” an Ocean Spray spokesperson told CNN Business. “This creates an air pocket on the rounded side (aka the top) so customers can “swipe a knife across the rim of the can to break the vacuum and the stem easily slides out.”

This method has been used since the early 2000s.

The costs are increasing

Ingredients for a traditional Thanksgiving meal will cost shoppers 13.5% more this year than last year, market research firm IRI predicted earlier this month using data from October.

This includes cranberry sauce, which is up about 18% in price year-on-year as the cranberry crop is smaller this year, resulting in a supply shortage.

The harvest of Wisconsin’s crop was “less than expected,” said Tom Lochner, executive director of the Wisconsin State Cranberry Growers Association, which produces a large chunk of the state’s cranberries.

“We’re scratching our heads,” he said, and are working with experts to get to the bottom of the cause. Right now he’s best transitioning from cold to hot to cool weather in cranberry growing regions.

“We’re still recovering from last year,” he said, adding that this year shouldn’t be short of cranberries.

Data from research firm IRI shows that fresh cranberries are actually cheaper this year than last year, with prices falling 9.9%. But that’s not the case for prepared cranberry sauces, where prices are skyrocketing.

Lochner pointed out that processors set these prices, not growers, and that there are higher input costs unrelated to berries — like “processing the fruit and getting it to market.”

Ocean Spray isn’t immune either. The company, a farmers’ cooperative, told CNN Business that it also had to raise prices for its canned cranberry sauce, but declined to give a specific percentage.

“Like many other companies, we have had to raise the cost of our sauce products slightly over the past year – for the first time in almost 10 years – to reflect current macroeconomic pressures and production costs for our 700 family farmers,” said a company spokesman.

–CNN Business’ Danielle Wiener-Bronner contributed to this report.