I stayed up watching a webinar from Cornell University about tannins in cold hardy grapes. Their research showed that the tannins were bound up by the protein in the grapes. My Marquette always had low tannin and I thought adding tannin during fermentation would bind the excess protein and then after racking the gross lees add more tannin to taste. Their research indicates it’s better to just wait till after fermentation and racking and actually wait till 6 weeks before bottling. They also found that adding tannin to cold hardy grapes does not help color stabilization, another reason not to add tannin during fermentation. So it changed my technique I’m going to use this year.
