Our cows are not treated with rBST. The FDA has sad that no significant difference has been shown between milk derived from rBST-treated and non-rBST-treated cows. Our Delicious Story. The 70's: It's 1976 and two childhood friend open their first ice cream parlor as a Double Rainbow lights up the San Francisco Sky. The 80's: A little recognition never hurts. Double Rainbow gets voted best ice cream in America. The 90's: Some local love. The Mayor of San Francisco proclaims Double Rainbow as the City's official ice cream. ‘Til Infinity: We remain a family owned business and continue our tradition of making award winning ice cream, using only the best ingredients. Thank you for being a part of our story doublerainbow.com. (at)doublerainbowicecream.