At this stage, we have five independent degrees of acetylation that we intend to run, but we will do so with two different degrees of hydration. The "expanded" system is the default, where the amount of water is unchanged by increasing acetylation and the name Table : Degree of acetylation based on water-exposed hydroxyl groups in lignin and hemicellulose. The % dry weight gain is computed based on Eq. 1. Distance from water (∞) represents the molecular system where all hydroxyl functional groups from lignin and hemicellulose are acetylated. In other words, 18% dry weight gain is the maximum acetylation possible in the molecular system of the plant secondary cell wall given the degree of polymerization.