I'm pretty new to the subject but I decided to do an all-grain Belgian Wit, everything went well and as it should until it was time to pitch the yeast, I used White Labs Belgian Wit Ale yeast, gave it a shake to mix it up just prior to pitching and when I open the cap it damn near exploded, not to mention it stress fermentation after about 5 hours ran really strong for 12 then absolutely died, and the beer seemed to separate (any portion of flavor and yeast on the bottom and water on the top). Has anyone else ran into this or could tell me what happened?