Vinegar and Water Can Deice a Windshield – Fiction!

Vinegar and Water Can Deice a Windshield – Fiction!

Summary of eRumor: 

A mixture of vinegar and water sprayed onto a frosty windshield acts as a cheap and effective deicer.

The Truth:

Vinegar can help melt ice, but it’s not an effective windshield deicer.

Various websites have repeated the claim that a 3:1 or 2:1 mix of vinegar and warm water act as a deicer. The eRumor goes viral each year as the winter months approach:

A homemade solution of vinegar and water can help in scraping the ice off a windshield. The acidity in vinegar will make the ice melt and allow you to use less effort to scrape the ice away. The homemade vinegar-water solution will also save money because you will no longer need to purchase expensive windshield deicer for your car.

In reality, all you have to do to make ice melt faster is lower the freezing point of water by adding particles to it. Salt, sugar, and almost anything else that forms a solution with water can be used, according to UC-Santa Barbara’s ScienceLine.

Temperature is an indication of how fast particles such as molecules, atoms, and ions are vibration. When liquid water is in contact with ice at the freezing temperature, liquid water molecules are vibrating slow enough to be captured on the surface of the ice… The rate of capture and escape is the same, and so the ice will remain as ice and the liquid water will remain as liquid water.

Salt is the most common additive used to speed up the vibration of particles in water to melt ice, but there are plenty of alternatives. Vinegar is mostly made up of acetic acid, which has been billed as a possible alternative to salt-based deicer, the University of Illinois at Urbana-Champaign reports:

Acetic acid has numerous uses as an industrial chemical, which need no further elaboration. Some of the salts of acetic acid are relatively new. For example, (Calcium-Magnesium Acetate) is being promoted as a road salt substitute. The cost of CMA may seem high compared to chloride road salts, which are available for $20-40/ton. However, we pay a much higher net price when the effects of chloride salts are considered, e.g., damage to highways, bridges, concrete structures, vehicles, roadside vegetation, ground water contamination and other environment effects.

The FAA has even approved CMA for use as a runway deicer at airports. But that doesn’t mean that you’ll have much luck deicing your windshield with diluted vinegar. The mixture may help lower ice’s melting point some and speed up the thawing process if the outside temperature is warm enough, but it would likely be more trouble than it’s worth.

In a video of an unscientific vinegar-water deicing experiment carried out by a radio station, the mixture took the top layer of ice off the windshield, but an ice scraper would have been needed to finish the job.

Still, many people argue that the vinegar and water mixture works if it’s sprayed on a windshield before ice forms. That claim has circulated for decades, as evidenced in this newspaper column from 1992:

Question: I keep my car outdoors at night during the winter. I use one of those cardboards on the windshield but it still ices and frosts up. What can I do to stop this?

Answer: Dip a sponge or cloth into a solution of three parts of either white or yellow vinegar to one part of water. The windshield should stay ice-free. Repeat occasionally.

Another theory is that a windshield coated in vinegar and water will still freeze, but the sheet of ice that forms will be easier to remove. The Glass Doctor website says:

Pour a mixture of vinegar and water on the windshield so that it freezes to the glass before the rain does, thereby preventing ice. Unfortunately, vinegar eats pits into the windshield glass.

However, the claim that vinegar eats into windshields may be overblown. The only types of chemicals that aggressively attack glass are hydrofluoric acid, concentrated phosphoric acid, concentrated alkali solutions and superheated water, according to the Corning Museum of Glass.  Regardless, be forewarned that vinegar could damage your vehicle’s paint or metalwork, so sticking with an old fashioned ice scraper might be your best bet.