In the four years since I wrote about cross-flow filtration (July 2006, WBM), the membranes—the heart and soul of the science—have continued to improve. Like a lot of technology, the cost of equipment is dropping. The most interesting development, however, has been the growth in mobile cross-flow services. This is key because it shows that even if winemakers still feel they cannot afford the equipment, more are willing to try cross-flow. Seeing winemakers embrace the techno...