[filleduchaos]

The recipe for soda is also open source - anybody can make their own carbonated soft drink. But I think if someone offered you "free soda" it would be pretty clear that they are offering you a specific soda whose recipe you almost certainly don't know, not the umbrella concept of "soda".

[369548684892826]

Coca-cola is a type of soda so... I think you're agreeing with me? Kind of hard to tell.

[filleduchaos]

"Free soda" and "free beer" are analogous, if that helps.

Or, since it seems to need explaining, the point is that "beer" is not one thing with one recipe and if somebody offers you "free beer" it is pretty obviously a specific kind and batch of beer.