It is now made by New Century Beverage Company of San Francisco, California, which was acquired by PepsiCo in 1986.

In 1936, New Century Beverage Company gained permission to franchise Pepsi-Cola products, and about four years later, it launched Belfast Root Beer.

[4] According to the San Francisco Examiner, the catchphrase, 'You haven't tasted Root Beer like this in years!'

"[3] An advertisement for Belfast Old Fashioned Mug Root Beer appears as early as 1952.

[6] Mug Root Beer is manufactured by independent bottlers under the authority of New Century Beverage Company.