But aren't you supposed to add the Fermaid at a 1/3 brix drop? You shouldn't even need a chart for that. For the end of fermentation, we use a specific hydrometer (https://morewinemaking.com/products/hydrometer-brix-5.html), so that it's as precise as we're going to get it. We always have some oddity with non-fermentable sugars, which are probably just part of growing grapes here, but the more precise hydrometer helps.
Hi Phil, To my understanding, after fermentation has begun, you cannot really get an accurate reading on the refractometer and that the hydrometer is much more accurate. It has something to do with the actual fermentation process. That's what I was told, so I use the refractometer up until crush, then I switch over. Always possible that what I've been told is wrong, but just passing along what I've heard. Kathy