Description of the lab:

Cinnamaldehyde was separated from a solution of water and cinnamon using steam distillation. The distillate was extracted with dichloromethane. The solution was dried over sodium sulfate to remove any remaining aqueous molecules and filtered through a Pasteur filter pipet to separate the solution and solid product. The solution was vacuum filtered to evaporate the organic solvent, leaving a pure cinnamaldehyde product.

The question is:

Most student IR spectra evidence a large O-H stretch on their spectra…regardless of whether they isolated eugenol or cinnamaldehyde. Hmm?…explain.