Susan,
We sell lemonade in a high-production theme park environment. We purchase 100% lemon juice from US Foods or Sysco; it is delivered refrigerated. This is not from concentrate. This is cheaper than squeezing it yourself, as the company will be squeezing ugly fruit, and you will buy pretty fruit and then squeeze it.
Our recipe is:
12 to 16 oz juice
enough water to total one gallon
1 to 1.5 cups sugar (this recipe is very flexible, as the tartness of the lemon juice fluctuates throughout the season.)
We started out squeezing our own lemons, doing 50 to 100 lemonades a day. When we got numbers above that; it became so labor intensive, our US Foods rep convinced us to try this product. We are very happy with it, and wouldn't use it if it were not as good as squeezing our own. We still add sliced lemon to the display,and sometimes to the cup, as this allows us the $1.00 premium over other drinks sold at our venue.
Best Wishes,
Phil and Rhonni
Phil still claims to be typing-impaired, but that might just be so that Rhonni feels needed.
Until that is remedied:
Rhonni's Blog
Rhonni on Twitter