Plant-based food company Impossible Foods will launch its Impossible Burgers in 27 Gelson's grocery stores across southern California on September 20. The Beyond Meat Inc. /zigman2/quotes/211617595/composite BYND +6.18% rival will add East Coast grocery stores later this month and continue to add grocers into early 2020, according to the Impossible Foods announcement. Impossible Foods is a privately-held company. The Impossible Burger is already on the menu at 17,000 restaurants, including Burger King, which offers the Impossible Whopper. Burger King is part of the Restaurant Brands International Inc. /zigman2/quotes/202094900/composite QSR +0.57% portfolio. To celebrate the launch, Impossible Foods is hosting events in California. Gelson's has been in operation since 1951. It will sell 12-ounce packages of Impossible Burgers for $8.99 in meat cases, both fresh and frozen.