Simply put, a percolator forces smoke to travel through water in order to filter it. This filtration cools the smoke and makes hits much less harsh. They come in many different designs, but all ultimately accomplish the same thing.
If you prefer smoother hits, or you’re looking for a healthier way to smoke, percolators are definitely something worth having in a smoking piece. There are three ways that percolators help you: Cooling – The smoke is extremely hot as it comes from the bowl, some lighters can get as hot as 3600 F / 2000 C. The water slows down the smoke’s path to your lungs, giving the smoke significantly more time to cool down. Additionally, forcing the smoke to interact with water gives it a chance to dissipate its heat into the water, which dissipates heat from the smoke better than air. Moisturizing – Another reason taking direct hits from a joint or pipe with no water filtration is so incredibly harsh is that the hits are dry. Forcing the smoke to interact with water causes some of the heated water to turn into water vapor, thereby moisturizing the hit, making the smoke less harsh on your lungs. Filtration – Filtration of the smoke occurs when the smoke makes contact with the water, therefore the more surface area of bubbles you have, the more filtration you have. This means that when the smoke interacts with the water, the water magnetically attracts polar contaminants, taking them out of the smoke. Water Filtration isn’t great at getting small contaminants or non-polar contaminants, but the filtration in addition to cooling and moisturizing makes for much smoother hits and happier lungs.
This is a common misconception about percolators and water filtration. Joint and pipe enthusiasts often complain that the water filters out the THC, which is why they prefer to not use additional percolators or any water filtration at all. However, if you’ll note my little chemistry lesson above, you’ll know that water is only good at attracting polar compounds from the smoke. Fortunately, THC, as well as many other cannabinoids, are non-polar substances, so the water would do a poor job at taking the THC out of the smoke. Anyone who’s made cannabutter with water has thrown out that water. You can throw the water away for the same exact reason. On the other hand, THC dissolves well in fats and oils because fats and oils are non-polar. This is why you can be confident that water filtration and percolators don’t decrease the THC content of your smoke. There has only ever been one study done on the matter. It suggested that water was indeed able to filter a minute amount of THC from the smoke, however the methodology has been disputed, and the study has never been repeated. Additionally, for the chemistry-related reasons stated above, conventional wisdom would say that THC isn’t filtered out of the smoke. Until a study definitively proves it one way or the other, we can’t be certain, but our analysis is that percolation does NOT filter out the THC. Ultimately you should weigh the evidence and make your own informed decision. While it is true that the additional cooling and moisturizing you get after the first one or two percolators is diminished, when it comes to filtration, you just can’t have enough percolation. Filtration occurs when the smoke makes contact with the water, so in order to get 100% water filtration, you need the surface area of the bubbles to be equal or greater than the surface area of the smoke. However the surface area of the smoke is many orders of magnitude greater than the surface area of the bubbles even with extremely effective and numerous percolators. Downstems are definitely the most commonly overlooked percolators. Before other percolators entered the market, downstems were the only percolators, and they are what set water pipes aside from dry pipes. Certain pipes are considered ‘stemless’ when they don’t have a downstem that comes apart from the water pipe as a separate piece, but even stemless bongs sometimes use stem percolators. The design is very simple, there’s a tube that reaches into the water and the air has to travel through it and comes out as bubbles. Adding holes, slits, or sometimes more complex mini-percs, on the end of a stem can increase the number of bubbles and therefore their surface area, thereby increasing its percolation power. The biggest advantage to downstems as percolators is their size / mobility. Since downstems are easily removed from a bong, they can be easily cleaned or replaced as necessary. If you prefer to like to use a simple, no percolator bong, we recommend spicing it up by adding an improved downstem, and you still keep all the benefits of your simple perc-less bong while retaining the additional percolation power. Tree Percolators are among the first percolators separate from downstems used in water pipes, and there’s a lot to say about them. If you understand its design, you understand perfectly how percolators work.
There’s a tube that goes up through the middle, that tube attaches to a bunch of arms up high, and those arms descend from that attachment point into the water. This way air comes from below and is forced up through the central tube and down the arms of the perc where it enters the water as bubbles. The arms are typically diffused with at least 2-3 slits in each arm. Although they are the most common, and probably exactly what most people think of when they think of a percolator, there are a lot of problems with their design compared to other percs. Anyone who has been around bongs for awhile has seen a tree perc break. For every arm, there is a joint attaching it to that main tube mentioned above. These connections are melted together, and usually are no more than 2-3mm thick at most. Even if they are 4mm+ thick, there’s always going to be a weakest link. Furthermore, smoke always takes the path of least resistance. The tree percolator’s design means that the top slits of each arm are closer to the water’s surface and therefore experience the least resistance.
This means that even though your tree percolator may have 10 slits down the side, only the top two or three actually have smoke go through them. Additionally, if your bong is tilted at all to one side, like many people do when they take a hit, one side will be closer to the surface than the other side, rendering half of the perc less effective. This can be a problem with almost all percolators to a degree, but it’s more pronounced with tree percolators.