Cranberry sauce is in high demand for Thanksgiving. But why are Ocean Spray cans upside down?

Cranberry sauce is a Thanksgiving dinner staple, although it can be divisive. 

Whether you prefer the canned classic or homemade cranberry sauce, it's part of the spread at most Americans' feasts, with more than half (51%) of U.S. homes planning to make it part of their big meal, according to an Ipsos survey of 1,020 adults.

Ocean Spray commands 70% of the canned jellied cranberry sauce market, according to AdWeek, and sells 67 million cans between Thanksgiving and Christmas.

But this holiday season, thanks to supply chain issues, products are harder to stock and some supermarkets don't have enough cranberry sauce. Publix, which has more than 1,280 stores in the southern U.S. including Alabama, Florida and Virginia, started limiting purchases of canned cranberry sauce and some other Thanksgiving essentials, including jarred gravy and canned pie filling, ahead of the holiday.

Research firm IRI found cranberry sauce available at 79% of retailers across the U.S. during the week ending Nov. 7, down from 89% during the same period a year ago, CNN reported.

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Ocean Spray had some of its own "supply chain challenges," the company said in a statement to USA TODAY. As a result, some consumers might have to opt for whole berry sauce or homemade sauce instead of jellied sauce, for instance. 

If you are lucky enough to land a can of Ocean Spray cranberry sauce, you might be wondering why is the rounded bottom of the can actually at the top? It's been an anomaly to many shoppers since the early 2000s.

The cans are "filled and labeled upside down with the rounded edge on top and the sharp can-like edge on the bottom to keep the jelly whole," Ocean Spray said in its statement. "There’s an air bubble vacuum on the rounded side, so the consumer can swipe the edge of the can with a knife to break the vacuum and the log will easily slide out."

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Contributing: Kelly Tyko, USA TODAY; Paul Nutcher, The Ledger in Lakeland, Florida.