So, I brought this up in another thread but I don't think I was very clear with my question. For a soda, has anyone done a mash simply to gather enough sugar to prime the bottle? No primary here, just mash-boil-bottle. I think that if you could get it right, you could get a great chewy body for a cola or root beer. You could just sweeten with a non-fermentable and you'd be set. Any ideas?
To me it makes immensely more sense to just sweeten with unfermentables, steep grains for malty character, and prime with dme. Going through all the trouble of a mash for a small amount of sugars just doesn't seem worth it.
Also, if you want to go through the trouble for something, I would say you could pasteurize (or at least refrigerate) a soda with natural sugars. I think it's the unfermentables that will have a greater effect on the flavor and mouthfeel of your soda as compared to where you get the actual sugars from.
At that point if you really want a malty soda, you could partial mash for a large portion of the sugars then bottle and pasteurize what is effectively a nonalcoholic sweet beer.