Gram positive organisms resist decolorization by ethyl alcohol.

Gram positive organisms resist decolorization by ethyl alcohol. The large crystal violet-iodine complex is not able to penetrate the peptidoglycan layer, and is trapped within the cell in gram-positive organisms. Conversely, the outer membrane of gram-negative organisms is degraded and the thinner peptidoglycan layer of gram-negative cells is unable to retain the crystal violet-iodine complex and the color is lost.

What is the purpose of using ethyl alcohol or acetone in the gram stain procedure: