Los Angeles-based Pabst, whose beer and malt liquor labels also include Schlitz and Old Milwaukee, has hired boutique investment bank Perella Weinberg Partners to assist with the effort, the people said on Saturday.

While the sale process is still at an early stage and detailed financial information is not available, Pabst is expected to fetch between $500 million and $1 billion, some of the people said.

One of the oldest breweries in the United States, Pabst is also considering an initial public offering as an alternative, two people added.

All the people asked not to be named because the process is confidential. Representatives for Metropoulos, Pabst and Perella Weinberg could not be immediately reached for comment.

Pabst was founded in Milwaukee in 1844 by Jacob Best and later sold to beer tycoon Paul Kalmanovitz. The company was later left in a charitable foundation after Kalmanovitz's death until a judge declared that it had to be sold.

Metropoulos, who works with his sons Daren and Evan, bought Pabst from Kalmanovitz Charitable Foundation in 2010 for $250 million.

The business has grown substantially over the years since his purchase and is likely to attract interest from both larger brewers and private equity firms, one of the people familiar with the matter said.

Worth $1.3 billion according to Forbes, Metropoulos has built a fortune turning around struggling food brands like Chef Boyardee, Bumble Bee Tuna, and Vlasic pickles. Metropoulos came to the United States from Greece as a child and has sold everything from milk to pickles to frozen foods over the last few decades.

In 2013, he teamed up with longtime partner Apollo Global Management (>> Apollo Global Management LLC) to buy Twinkies, Ding Dongs and Cupcakes from bankrupt Hostess Brands Inc for $410 million.

Dean Metropoulos has served as an executive at companies such as the Morningstar Group, which became Dean Foods (>> Dean Foods Co), Duncan Hines cake mix maker Aurora Foods, Ghirardelli Chocolates, and Mumm and Perrier Jouet Champagnes.

He also ran Chef Boyardee and Pam cooking spray maker International Home Foods, which was sold to ConAgra Foods Inc (>> ConAgra Foods, Inc.), and Pinnacle Foods, maker of Vlasic pickles and Log Cabin syrups. Blackstone Group (>> The Blackstone Group L.P.) bought Pinnacle in 2007 and took it public last year.

(Reporting by Soyoung Kim and Olivia Oran; Editing by Diane Craft)

By Soyoung Kim and Olivia Oran