So I've got a question about natural carbonation. I'm fairly new at this, and from what I gather dry & bubbly or sweet & flat are the typical naturally carbed options, leaving aside artificial sweetener and non fermentable sugars. I don't mind, I'm not much for sweet. I'm curious though; let's say I made a beer with an 8% tolerant yeast using less sugar than required to get to 8% ABV. Let's assume that every time the fermentation got really slow I added a bit more sugar until I got to a dry 8% brew, with little to no fermentable sugar remaining. If I were to add a different, more alcohol tolerant strain of yeast (say 10%) and enough sugar to ferment in theory to 15% ABV then keg it would this be a practicable way to get a "sweet and bubbly" brew? Or would I just end up with an exploded keg because yeast mutation means that some would be sufficiently hardy to survive past 10% ABV and would eventually produce too much CO2?