Thank you, that was quite interesting. :)
To reach more of the public, it began to be bottled and distributed through general stores in a 6 1/2 oz. bottle.
Competitors emerged, and Pepsi began to compete at labor intensive work site lunch counters in hot climates with its ten oz. serving. It offered more cool beverage and sugar for the same price.
Therefore, the brand of drink took on a class distinction in the South, which is reflected today by ordering by brand. Other locations, North and West simply saw the drinks as ‘pop’ or ‘soda’ without volume, taste, or origin discrimination.