The overall change in hydrophobicity for the cell wall upon acetylation is perhaps best quantified by visualizing water pockets within the cell wall (Fig. ). Comparing end states from our simulation, we see that the water will often cluster together into the voids left by the cell wall polymers. The voids are visually much larger in the unacetylated cell walls when compared with the fully acetylated structures (Fig ). Quantitatively, the removed water when acetylating the "constant" system is effectively all taken from the bulk water voids, as the bulk water fraction shrinks considerably upon acetylation (Fig. ). Indeed, the bulk water fraction is approximately 8× higher in unacetylated cell walls, and is far in excess of the change in hydration level alone, which only changes by approximately 50% (Table ).