There is a yellow ring around the top of the wine in my carboy, but the wine tastes and smells fine. What’s with the yellow ring?

Dear Wine Wizard, My partners and I, for the first time, bought Merlot grapes last year. We followed our normal procedure, which we have been using for the past five years for the red grapes we used, including Zinfandel, Barbara and Carignan. We plucked about 75 percent of the grapes off the stems prior to crushing. We used pasteur Champagne yeast and the grapes were in the primary fermentation container for five days. We now have the wine in carboys. It has cleared up in good shape but there is a yellow ring around the top of the wine. The wine tastes good and has a good aroma, but what’s with the yellow ring? Dan Bowers Kenosha, Wis. Wine Wizard replies: Sounds like ring around the bathtub to me! Or maybe we should call it ring around the fermenter! Going on the information you’ve given me and if my wino intuitions are correct, your “yellow ring” is probably a deposit of post-fermentation residue, especially if you put the five-day fermented wine into the carboy before the wine had finished fermenting