For this review, I headed to CNET’s Product Testing Lab in Louisville, Kentucky, to conduct an extensive batch distillation experiment using eight of the most commonly used chemical drain cleaners on the market. My primary goal was to determine each product’s effectiveness at dissolving different types of clogging materials, including organic matter, grease, paper products, and pet hair (the same pet hair we use for our robot vacuum tests, by the way). Throughout the experiment, I also noted the pH levels of the cleaning solutions when mixed with water and monitored any changes in temperature. I also took into account the chemical makeup and versatility of use of each product when comparing them to one another.
Acids vs. Bases
Before I did any experiments with these substances, I separated them into acids and bases. As you may remember from high school chemistry class, acids are compounds that release a hydrogen ion (H+) when mixed with water and have a pH less than 7. Bases, on the other hand, are compounds that accept that ion (or hydroxide, OH- ions) and have a pH greater than 7. Understanding this distinction is crucial, because of two major factors associated with these products: corrosiveness and causticity.
Corrosivity refers to the potential of a chemical substance to cause rust and deterioration of the materials that make up your plumbing system. Causticity, on the other hand, refers to how a chemical substance reacts when it comes into contact with organic material, specifically breaking down proteins and other organic molecules, which can lead to tissue destruction or chemical burns.
To determine the acidity or basicity of any compound, we measure their pH. Simply put, the more acidic or basic a compound is, the greater the potential for corrosiveness and causticity.
Example of the pH value of one of our test subjects. A pH of 11.38 corresponds to an alkaline solution.
Acidic drain cleaners, especially those with high acid concentrations such as sulfuric acid drain cleaners, are more dangerous compared to their basic or alkaline counterparts. In chemistry, the order of addition matters. Normally, you would add an acid to water gradually, slowly increasing the concentration of the acid. Never add water to an acid because this reaction is known to generate significant heat and release hazardous fumesS. See for yourself in the GIF below (don’t try this at home).
Adding water to this beaker of sulfuric acid will cause an immediate exothermic reaction, boiling the water on contact and releasing dangerous fumes into the air. Don’t try this at home!
To ensure safety during the experiments, I took the necessary precautions by wearing personal protective equipment including safety glasses, gloves, long sleeve clothing and a mask. The dissolution test was performed in a well-ventilated laboratory space to minimize exposure to any hazardous fumes that may be released.
Dissolution test
To start the experiment, I weighed out specific amounts of the clogging materials into separate 1000 ml beakers:
- 4 grams of hair
- 20 grams of organic material (10 grams of apple and 10 grams of carrot peels)
- 40 grams of lard for fat
- 14 grams of paper products (7 grams each of toilet paper and paper towels)
Using a graduated cylinder, I carefully measured out 200ml of each basic drain cleaner and 70ml of each acidic drain cleaner and added them to their respective beakers, stirring the mixtures with a glass rod, ensuring thorough mixing without spilling. I followed the instructions that came with each product and allowed the solutions to sit for the recommended amount of time, usually between 15 and 30 minutes.
A crucial step in my testing was the addition of water, a component often overlooked in similar experiments found online. Chemical drain cleaners are designed to work in the presence of water, which facilitates the transport of the cleaner to the clog and distributes the solution evenly across their surfaces, facilitating the dissolving process. After the specified time had elapsed, I added tap water to each cup containing the cleaning solutions and drain cleaning materials. For basic drain cleaners (pH > 7.0), I used 500 ml of hot water at 46 degrees C, while for acidic drain cleaners (pH < 7.0), I used 700 ml of cold water at 19 degrees C.
To give the chemicals enough time to work, I let the samples sit overnight and resumed evaluation the next morning. By this time, the samples had turned into sludge-like, slimy mixtures.
Hair solution test in progress
To continue the experiment, I used a vacuum filtration process with a Buchner funnel connected to a 1000 ml filter flask equipped with a pump. The contents of each beaker were carefully poured into the funnel while the pump was activated. After most of the chemical drain cleaner had been drawn out of the funnel, I performed a water wash to remove any remaining chemicals from the surface of the debris samples, making sure that only wet solids remained in the Buchner funnel.
Our Buchner funnel, made of chemically resistant borosilicate glass, had a perforated plate with 2mm openings, which allowed only the tiniest particles to pass through. In my test logic, “if a substance, solid or liquid, could pass through the 2mm openings in the filter, it was very unlikely to cause blockages in the pipe.”
On the left is our vacuum filtration setup. Liquids and dissolved solids pass through 2 mm holes in the Buchner funnel plate on the right. Anything that does not pass through is considered potential clogging material.
Finally, I separated the samples and subjected them to a fan drying process for a few hours to evaporate the remaining water from the wash. I recorded the final weight of each sample and compared it to the original weight. The ratio of the final weight to the original weight gave us the dissolving efficiency of each drain cleaner product.
