Beer and Brewing Journal

One question that concerned me about stir plates is understanding if your yeast is alive and working on your DME based starter. Without a stir plate, you will see a krausen develop and movement within the wort. Since the starter is in constant motion on a stir plate, the krausen never develops. I guess you could check the gravity but that seems like a lot of extra work, plus you may have a small starter (1000ml or less). One easy indicator to determine good activity is a fairly dramatic lightening of color after 12 hours (I make my starter the night before and then check it in the morning), this is a good sign that your yeast is working: