All brewers encounter a fermentation problem at some time during their working career. Many variables exist in brewing, and the nature of a live organism performing the fermentation can make it difficult to pinpoint the cause of a fermentation issue. From a yeast standpoint, the condition of the yeast itself plays a crucial role in determining the probable source of problems. The critical question is, how do you know if yeast is in good condition? Learn some approaches to deduce the cause of fermentation issues.