If during the fermentation I get any major off flavors, I'll extend the time in the fermenter to see if the yeast cleans them up.TBH, my discretionary testing ability is not so great — somewhat embarrassed to say so. I think it’s “fun” to taste it when the wort cools and at bottling time but I can’t say what am tastings means this or that. I wonder if tasting during, say, the middle of fermentation tells one anything important?