What's in the coffee in Canada? Apparently something that's making a few folks pretty generous.

At least six times this week, customers at Tim Hortons restaurants have paid for their own cups of coffee and cups of brew for the next 500 or more people in line, according to media reports.

The first 500 free javas were gifts of an anonymous donor at a Tim Hortons in downtown Edmonton, Alberta, on Monday, CTV reported. A man in his 20s bought a double-double and a doughnut and told the clerk to put the next 500 large coffees on his debit card, according to the report.

"(The staff was) thinking maybe he was so blessed that he wanted to share his blessing, or maybe he won the lotto or something," store manager Joanne Averion told CTV.

The act has been repeated five times since, in Calgary, Alberta, on Tuesday, in Ottawa and Red Deer, Alberta, on Thursday, and two more times again in Edmonton on Thursday, according to the Canadian Broadcasting Corp.

Read - Canadians paying the coffee forward - by the hundreds