Brewed an Amber and everything was spot on with a perfect mash (ph 5.25 @ 154 degrees) and a OG of 1.059. Used WLP550 with a 1liter 24hr starter. Wort started chugging along after 12 hours and went like a dream for 4 days and then it came to a screeching halt at 1.020. Tried to rouse the yeast...