It's a scorcher of a day in MA, so I decided not to sweat to death while ripping out some sod for my sidewalk project and spend the day dealing with wine because it's cooler in the basement. The sauvignon blanc has been chilling in an ice bath since Saturday morning, so it really needed to be racked anyway. At least that's my excuse and I'm sticking to it!
It looks like the MLB activity has subsided upon cooling, so I racked off the lees into newly sanitized carboys. With a pH = 3.2 and free SO2 levels around 35-40 ppm, I'm frankly a little flummoxed why the bacteria was active. Those free SO2 levels should give >1 ppm molecular SO2 at that pH and that's way more that the 0.8 ppm that's generally recommended to suppress microbial activity. Generous SO2, low pH, and lysozymes should be more than enough to keep the MLB in check. I added another 25 ppm SO2 for good measure and now I'm going to let the wine warm up. I need to bentonite fine this wine in a few weeks, so I don't want to add more lysozymes now as the bentonite will strip the lysozymes out of the wine along with any other proteins. Going to give the SO2 a chance to work while I'm getting ready to fine. Let's keep those fingers crossed.