this is one of the most advanced rain jackets ever invented it was specifically designed to overcome one of the biggest problems that has plagued modern reindeer and it's this jacket that helped me realize that gortex is a complete and utter scam let me explain gortex was discovered by Bob Gore in 1969 after years of working at deont helping to develop polyfluorinated chemicals but known as Teflon or forever chemicals they are now known to wreak havoc on the environment and the human immune system doing over those so-called forever chemicals that have made it into waterways and even our own bloodstreams to the extent that Dupont was sued when it was discovered they knew fluorinated chemicals were bad for us but covered it up because they didn't want to stop selling Teflon she uses resol carpet cleaner with Dupont Teflon like seriously there's a whole movie about it well when Gore discovered that if you heat up and rapidly stretch those same poisonous fluorinated chemicals it creates a porous membrane with thousands of microscopic holes each one just large enough for Vapor to pass through but too small for water to enter he left to Pont and started the brand that we now know as gortex and began marketing his Discovery as the ultimate breathable waterproof fabric gortex guaranteed to keep you dry this is where I take issue you see gortex is in fact waterproof with an impressive hydrostatic head rating if I clamp it over this pipe fill it full of water and then pressurize it with air it takes over 40 PSI before it begins to fail that's the equivalent of over 20,000 mm of hydrostatic head the problem is while gortex is in fact breathable and waterproof it's not always breathable and waterproof at the same time let me show you so gortex really does have microscopic holes too small for water to enter but big enough for Vapor to escape but that Vapor can only Escape if the outermost layer of the fabric isn't absorbing water if the outer fabric becomes saturated Vapor can't escape and instead just recondensed back in a water drop that get you wet from the inside out to prevent this from happening gortex treats all those jackets with more those poisonous fluorinated chemicals to create a water repellent finish that causes water to bead up and roll off the outer layer this is known as dwr or durable water repellent finish and despite the name it's not very durable and needs to be reapplied multiple times throughout the life of the jacket once the dwr stops working we call that wet out and sweat can no longer escape from the jacket getting you wet from the inside out and that's where this jacket comes in you see this isn't gortex but it actually kind of is you see the gortex patent expired in 1997 which has allowed companies like Colombia to make their own version of the breathable membrane the only difference between this and gortex is this doesn't need the dwr coding to work properly most gortex jaggets have three layers of fabric an outer layer that gets coated in dwr the waterproof membrane in the middle and the inner fabric so that it feels soft against your skin but this jacket has eliminated that outer fabric which means what you are looking at now is the membrane itself and since that membrane is 100% waterproof it can't absorb water and theoretically Never Wet out but I wanted to test it to see if it really does work without dwr so I came up with this this is my best attempt to simulate the human body in a measurable repeatable way what I have here is a small tray of water that is being warmed up by a small Heating element attached to a thermostat to keep the water at body temperature I fill the tray with 120 g of water and clamp the jacket over the top I let the whole thing sit for 2 hours and then weigh the tray to see how much water has evaporated you see I wanted a way to quantify what I've always experienced in the field that when it's raining and humidity is relatively High these jackets don't seem to breathe very much at all so I also built this humidity control chamber where I can measure to see how much Vapor passes through these jaggets in a variety of conditions I tested the jacket at low humidity high humidity and with water raining on the jacket and discovered that in order for these jackets to breathe even a little bit they need a very specific set of circumstances but also the air Can Only Hold so much water vapor at each temperature this is Dr kosa sua chadov assistant professor of corporate extension in the field of biometeorology at the University of California Davis so we need to have the capacity or thirst of the atmosphere to drive that evaporation think of the air like a giant parking lot and water molecules are like cars looking for a place to park when the humidity is low it's like the parking lot is empty and it's really easy to find a place to park but when humidity is high it's like the parking lot is almost full it's not only going to be harder to find a place to park but it's going to take more time once the air reaches saturation the parking lot is full and no more cars are going to be able to park at all the air is saturated at the point that it's becoming at the equilibrium it's not going to drive that sweat to dry but that's only half the problem this jacket acts like a divider creating two different environments conditions under the jacket and outside of the jacket are both very saturated imagine you have one smaller parking lot on the inside of the jacket and one much larger overflow lot outside the jacket if the smaller parking lot is full cars will naturally want to leave to go to the Overflow lot but once the Lots reach equilibrium there's no reason for cars to leave the smaller lot because there's still room to park inside the jacket so these jackets will do best when the humidity outside the jacket is low like when it's snowing in dry Colorado but when humidity is high like the rainforest of the Pacific Northwest they don't do very well at all but once again that's only part of the problem the other is air movement one of the things I discovered early on in my testing is if there's no air movement you get absolutely no evaporation so not only do you need low humidity you also need some way to introduce air flow into the jacket which I did by adding this little fan inside my test rig that is very calm we have the water surface and then we have a thin air that can get very quickly saturated and then when you turn on the fan it's mixing more efficiently that lamin of air and this prompted a very serious question one that I haven't yet figured out how to measure how much air movement can we realistically expect inside these jackets because these jackets are also designed to block wind so you aren't going to get very much air flow without some sort of ventilation like pit Zips and the problem with that is if you're using pit Zips do you really need a breathable jacket and does it even matter because anytime it's raining humidity is naturally going to be High I mean water is literally falling through the air that's what rain is and anytime humidity is high that leaves little to no room in the air to accept any more moisture which means sweat can't evaporate and leave your jacket and that's why I say that gortex is a scam because even though it is waterproof and it is breathable it can't do both of those things at the same time the science just won't allow it so what about all the people commenting on this video saying well my gortex has never let me down well when you spend anywhere from $300 to $500 for a waterproof breathable jacket you don't want to believe that you've been scammed it's called confirmation bias and it's part of what has allowed gortex to profit off of poisonous chemical riddle jackets for so long the key element in all gortex products is polytetrafluroethylene PTF because we believe their marketing hype but this video is your permission to stop and so you might be thinking okay Stephen if gortex isn't waterproof well then what do we do well I recommend you watch this video right here all about alternatives to Modern rain gear hope you enjoyed this video please like subscribe and do all those other things and as always thanks for watching