Two baffles were added to the distillation column, and the few leaks in the condenser were fixed. The two litres which had been distilled off previously were returned to the vessel, so that there was again 10 L of 10% ethanol. This was distilled, and density measurements were made for the first 250 mL, the first 850 mL, and the first 500 mL of the second litre.
The first litre distilled had a higher ethanol concentration than the first litre distilled in the previous run. This could indicate that the baffles help raise output concentration. The density measurements seem to be a reasonable way to estimate the ethanol percentage.
More baffles should be added to the column to see if this further increases the quality of the yield.