Around the same time as we changed the mill size, we got a lot pickier about the timing of the heads cut, and stopped recycling any heads. So the final product yield actually went down, but there were multiple factors involved (as usual, we changed too many things at once!). Anyway, I think I've read that some methanol can come from one-off ferments of cellulose, but Silk City is right that the literature seems to support the idea that the vast majority comes from pectin.
This is off my original topic, but what ferment temperatures are folks generally using? There's a wide range of answers on the web! We do control ferment temperatures pretty tightly, but our target is typically 87F +/-2. Any thoughts about that being too high, and producing more fusels, etc?