Water tastes different to different people. Water that is devoid of all minerals (distilled water) tastes like sandpaper. I'm from Northern Michigan. Our water is known to have very high iron and copper content. It tastes great to me, but most people who visit here can't take it. As I have...
Drink 4 or 5 with a friend and see if you get sick on it. If you don't, make up a name for it and serve it! Its your own creation. If you want to call it Hefe, no one is going to be upset.
Personally, I'd be putting the "drink at your own risk" sign on the commercial keg, not yours ;)
Hefe's are quick. A week ferment and a week to carb. In my experience, a simple Brown will do the same thing. Better than Bud in about 2 weeks. Rushed, by most standards. But its good beer :mug:
Personally, I'd drink the 1.017. That isn't that high. I if you just let the 1.021 sit, it will still fall a few points. If it really isn't going any farther, drink that one too. Whats the worst case? It probably still tastes good :mug:
DMS is Dimethyl Sulfide. It tastes like corn on the cob. It makes beer taste like vegetables if there is enough of it. You will know as soon as you drink a bottle that has high DMS content.
I very seriously doubt high humidity will lower the evap rate enough to prevent boiling out DMS. The...
You could just buy some drinking water and brew it. See what happens. Try brewing without any plastic containers. They can retain nasty critters from previous batches.
DMS production? I doubt it. But more DMS might remain in the wort during the boil. Remember, the main reason for DMS flavors comes from leaving the lid on the boil pot, then the condensation (saturated with DMS) falls back into the wort.
Just don't cover your boil pot, and I doubt you'll have...
As humidity increases, it becomes (mathematically) exponentially more difficult to create more water vapor. Barometric pressure also plays a role. Air at high pressure can sustain less water vapor than can air at lower pressure.