In this very comment section an earlier post claimed the opposite (that specifically grain fermentation did not produce the big M), and sounded just as knowlegable and plausible to the lay-ear.
The primary mechanism of methanol production during fermentation is from pectin degradation. Grain contains considerably less pectin than fruit, so grain fermentation produces less methanol than fruit.
The primary mechanism of methanol production during fermentation is from pectin degradation. Grain contains considerably less pectin than fruit, so grain fermentation produces less methanol than fruit.