Percolators: The Effectiveness of Water Pipe Diffusion

Water pipe technology sure has changed dramatically over the past couple decades. One of the most notable innovations, the percolator (‘perc’ for short), has become a very common and desirable feature for many smokers. But what is the appeal of these glass contraptions, and are they worth the increased cost of the pipe?

A simplified look at how a percolator functions.

A simplified look at how a percolator functions.

A percolator is fundamentally a means to increase the smoke’s water contact area within a water pipe. This effect is visible as a multitude of bubbles and is often referred to as diffusion. For example, holes at the end of a down-stem are often referred to as a diffuser or diffuser tip, and can be also be considered a percolator of sorts.


Diffusion provides more than merely a visually pleasing bubble effect in your pipe – it creates a smoother hit for the user. This is caused in part by the cooling effect that water has on smoke or vapor. The more water the smoke makes contact with, the more it cools down; a cooler hit means a smoother hit. That’s why dry pipes can be somewhat harsh – the smoke isn’t cooled off very much before it gets to the user’s lungs. The cooling effect is also why many smokers like to fill their water pipes with ice before use.


In addition to cooling the smoke, diffusion actually helps to filter it as well. When you burn any organic material, including plant material, there’s generally going to be at least some amount of undesirable toxins that are released. These toxins not only make for a harsher, cough-inducing toke but also can negatively impact health. For this reason it would be ideal to filter out as much of the undesirable by-products as possible. Percolators can do just this.


The filtering effect of diffusion has been known and studied for decades. Back in the late 70’s, a group based at the University of Athens Medical School conducted a series of chemical and pharmacological studies on marijuana and tobacco smoke. After running marijuana smoke through water, chemical analysis revealed many different compounds in the smoke and in the water, as is expected from the combustion of plant materials. The water did trap some THC, as well as other psychoactive compounds; however, most of the THC present in the marijuana passed through the water pipe unchanged.


The research shows that water filtration reduces both the amount of particulate matter and the number and quantity of toxic substances in the smoke that passes through it. Nicholas V. Cozzi, Ph.D., refers to the aforementioned study and several others in a 1995 research document. In his conclusion he further validates the concept of water pipe diffusion:


“The effectiveness of toxicant removal is related to the smoke’s water contact area. Specially designed water pipes, incorporating particulate filters and gas dispersion frits would likely be most effective in this regard; the gas dispersion frit serves to break up the smoke into very fine bubbles, thereby increasing its water contact area. While individuals vary greatly in their smoking technique, state of health, dosing regimen, and so on, it seems that many patients could benefit from the use of water pipes to deliver THC. This would allow patients to titrate their dose easily while reducing the health hazard associated with smoke.”

Diffusion can be a godsend when smoking flowers, however many prefer to minimize diffusion when using concentrates. This is because most of the toxins present in plant matter has already been filtered out to create the concentrate product. For this reason, many concentrate rigs are built in a smaller form factor, and with just enough diffusion to cool off the smoke but not enough to collect a substantial of the THC from it. Glass artist Tye Whelan of Hard Times Glass touches on this concept and the resulting design of his pipes in an interview with us at the American Glass Expo:


Check out our gallery below to see some of the various percolator types. These items are all available in our online store.


What’s your favorite diffusion design? Let us know in the comments!



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