I am making a batch of Cabernet using Lavlin wine yeast and fermenting in glass carboy at 62deg. OG was pretty high. According to the instructions, secondary fermentation should be about 2 weeks. Mine is still bubbling away after 5 weeks. Should I continue to wait until active fermentation slows before the final racking and addition of campden tabs? I'm concerned that the campden tablets will prematurely halt fermentation.
Yes, I would wait. Also, try to warm it up. The cool temp is probably the reason for the slow ferment. I like to ferment Cab upwards of 78 deg. F. or more. Perhaps you can put a heating pad under the fermentor or put on a brewing belt.