No "probably" about it. The price of entry into a supermarket's inventory is often a discounted-enough rate on white-label stuff that they can sell right beside you. I got an education stocking shelves at a supermarket as a kid. Pretty hard not to make the connection when the bakery dropped off loaves of store brand and their brand, intermixed in the same trays, and we had to separate them out.

> The funny thing is that they probably use the same manufacturers as the popular brands and just also a different label on it.

They absolutely do. For example, Costco has two Kirkland Signature vodkas. One of them is Grey Goose, and the other I forgot. Skyy? Same goes for their tequila, it's all Jose Cuervo.

Look up Frank-Lin distillers sometime.

https://ello.co/dredmorbius/post/bztu6ot3xumpeiiiygdzaa

http://www.frank-lin.com/

http://www.dailyrepublic.com/news/topstories/fairfield-offic...

http://www.webcitation.org/5jjmHRr9C

and the rest of the grocery stores are probably safeway..