Looking back at my early years, the First Lite Uncompahgre Foundry Jacket would have been a welcomed piece of gear. I spent many weekends during those younger years tromping around the mountains of southern Idaho chasing deer and elk in cotton, flannel, and jeans. My outer layer for colder hunts was an extremely heavy (and not very warm) army surplus coat that was barely water resistant, let alone waterproof. That “coat” had to weigh at least five pounds. Any inclement weather usually meant our day on the mountain would soon be over after our clothing was soaked through.
Despite the inadequacies of my gear, my family managed to consistently fill a lot of tags with some nice headgear to boot. A couple decades later, I look back at that era wondering how many more tags we would have filled if we could have stayed out in the field longer on some of those wet, cold, and windy days. Back then, I thought “that’s the way it is” and never could have dreamed of the advancements in technology of today’s hunting clothing.
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Enter First Lite. Founded in 2007, First Lite has long been an industry leader in hunting apparel with a particular specialty of merino wool products. After First Lite and 37.5 teamed up, the partnership blossomed, and 37.5 is incorporated into a large portion of current First Lite offerings. I had the opportunity to test out the Uncompahgre Foundry Jacket in a wide variety of conditions and temperature ranges to see how it performed over the past seven months.
What is 37.5 Technology
Before diving into the details of the First Lite Uncompahgre Foundry Jacket, I was interested in better understanding the technology behind 37.5 and why it works so well. The overall concept is quite simple – pair merino wool’s moisture wicking and odor eliminating capabilities with 37.5 Technology’s ability to help your body naturally regulate its temperature by using fabric that keeps you cool when it is hot, and warm when it is cold.
The technology behind 37.5 is not quite as simple. 37.5 Technology was first “discovered” in 1992 by a Ph.D taking a volcanic sand bath in Japan on Mt. Aso. I had no idea what that even meant and had to do some research.
Mt. Aso is the largest active volcano in Japan. The hot water beneath the surface heats up the sand. Bury yourself in the sand with a temperature range of about 122-131 degrees, and you can take a toasty “sand bath.” The suggested health benefits are that the heat makes you sweat, which then expels toxins and inflammatory/pain-causing substances from the body. The warm sand promotes blood circulation, supposedly leaving you refreshed.
Circling back to 37.5’s roots, the Ph.D. found that the volcanic sand removed sweat vapor so quickly that it continually cooled him via sweat evaporation. This evaporation helps remove sweat vapor before it turns to liquid which equals better control of retained body heat via evaporative cooling. This concept became the foundation and First Lite, paired with 37.5 Technology, has been perfecting pairing the proper amount heat gain with heat loss as the magic formula in their merino and synthetic apparel ever since.
Interested in learning more about the finer details of 37.5? Take a look at their up-close videos, scientific studies, and literature on the technology here: www.thirtysevenfive.com/thermoregulation-technology/. It is fascinating!
The Testing: First Lite Uncompahgre Foundry Jacket
I was fortunate to spend north of 40 days in the field this summer and fall with the First Lite Uncompahgre Foundry Jacket with me the entire time as my primary outer layer. This jacket was in my pack for all seven of my backpacking trips from May through August, and on all four of my 2024 archery and rifle hunting trips from September through November with wind, rain, snow, and temperatures down in the single digits. After a full season of use, I can safely say I have put this jacket to the test… and then some.
Features: First Lite Uncompahgre Foundry Jacket
The First Lite Uncompahgre Foundry is absolutely LOADED with features:
- Built with 37.5 Active Particle Synthetic Insulation
- 2-layer laminate windproof and waterproof shell. This jacket truly is windproof and built to handle the wind and harsh terrain.
- “3-way” adjustable hood with channel brim. Great for keeping the hood from drooping over your face. The adjustable brim can be modified to the conditions to keep snow or rain off your face/hat.
- Tricep vents on each arm allow for dumping heat without removing pack or bino harness
- Two-way front zipper.
- Front of the jacket has two zip-closure hand warmer pockets with plush warm tricot lining
- Two magnet closure dump pockets for additional storage adjacent to the zip-closure pockets
- Internal mesh dump pockets for easy storage close to the chest
- Cuff gusset helps trap heat at the wrist and protects elastic cuff material from moisture
- The Uncompahgre Foundry Jacket is insulated with 100g of 37.5 Active Particle Synthetic Insulation on the body and 60g on hood/sleeves.
- DWR package repels moisture.
- YKK Aquaguard zipper
- Intended for use as an outer layer in your kit
- Listed weight on First Lite’s website: 2lb, 2.5oz (34.5oz)
- Note the actual weight from my scale of the size XXL jacket I was using: 2lb 9oz (41oz). I’m assuming the listed weight on First Lite’s website is from a smaller size, but I have not verified this with First Lite directly.
I have long been a fan of First Lite’s Uncompahgre Puffy Jacket for packable, lightweight, insulation and have owned and used the original and 2.0 versions of this jacket for years.
For comparison’s sake, think of the Uncompahgre Foundry Jacket as the Uncompahgre Puffy’s big brother who takes steroids and spends a lot of time at the gym. The outer shell has a very different/rougher feel than the material of the Chamberlain or Puffy. The Uncompahgre Foundry is built to handle the toughest terrain while easily having the versatility to double up as a rain jacket, if necessary.
My Favorite Features: First Lite Uncompahgre Foundry Jacket
1). Tricep vents for cold weather hikes – They worked amazingly well in keeping me warm, but also helped air circulate to prevent excessive sweating.
2). Adjustable hood – It is always annoying to wear a jacket that has a hood slipping over your eyes, and the Uncompahgre Foundry solves this with the hood being adjustable with a draw string at the back of the head to get the fit absolutely perfect for the individual user.
3). Storage – The variety of pockets allow for storage of calls, phones, gloves, or any other smaller items in the inner or outer preferred pocket. The dump pockets are especially handy for not having to mess with zippers in extreme cold. I should note that the pocket configuration is different than other First Lite jackets I have previously used, with the magnetic dump pockets being directly adjacent to the tricot lined hand warmer pockets on the front of the jacket. This took a bit of getting used to, but I came to really enjoy this feature as both sets of pockets are useful.
4). Fit – I am 6’4”, 220 pounds, and I would say the XXL jacket fits true to size, with plenty of room for layering underneath. If you are not layering underneath this jacket or prefer a tighter fit, consider sizing down.
5). Waterproof – The DWR works fantastically. Multiple times, I spent extended periods of time in the rain and snow and had zero complaints with moisture soaking through the jacket. Moisture beads on the jacket exactly like you’d expect with the DWR coating.
Again, this jacket is loaded with features and is extremely versatile depending on your particular usage and needs.
Comfort Range: First Lite Uncompahgre Foundry Jacket
Using a proper layering kit using like the First Lite Wick as my base layer, First Lite Kiln as my second layer, and the First Lite Origin Hoody as my third layer, I was able to comfortably use the Uncompahgre Foundry Jacket as my outer/fourth layer during minimal exertion with temps down into the teens. If the mercury dropped much colder than that, or with notable wind during early morning glassing sessions, I found myself getting a bit of a chill and needed to add an additional layer.
For reference, I tend to run a bit cold and oftentimes find myself layering up more than some of my hiking or hunting buddies. I’d venture to guess that the lower limit of this jacket will vary somewhat for the individual.
Durability: First Lite Uncompahgre Foundry Jacket
The Uncompahgre Foundry Jacket is extremely durable when busting brush or navigating thick country. I made it a point in my usage of this jacket to do it no favors and made zero effort to avoid snags, thick brush, and deadfall. After over 40 days in the backcountry, I have not been able to find any damage whatsoever. The only “downside” to this durability is the additional weight.
Comparatively, the Uncompahgre Foundry is slightly heavier than several of the other First Lite Jackets that I would consider to be the same usage category from First Lite’s lineup:
- First Lite Uncompahgre Puffy Jacket 2.0 – Listed weight: 21oz. Actual weight of size XXL: 24oz
- First Lite Chamberlain Down Jacket – Listed weight: 25oz. Actual weight of size XXL: 31oz
- First Lite Uncompahgre Foundry Jacket – Listed weight: 34.5oz. Actual weight of size XXL: 41oz.
I own and use all three of these jackets for different purposes/conditions but would not hesitate to heartily recommend all three of them. That said, if you’re an ounce counter, the weight is something to pay attention to, and the best pick for your needs will likely depend on your primary usage and the terrain you plan to hunt.
The Chamberlain and Puffy are fantastic options but will be more likely to tear due to lacking the thick outer shell of the Uncompahgre Foundry. The Chamberlain (a down jacket) will obviously be extremely warm, but will not stand up to moisture as well as the Uncompahgre Foundry does over extended periods of time in inclement weather.
Warranty: First Lite Uncompahgre Foundry Jacket
In the event of an issue with durability, First Lite does offer a “Practical Lifespan” warranty, defined as the “customary wearable life of the product.” As with any piece of clothing that is heavily used, it won’t last forever, but can be warrantied if it has a manufacturers defect or if the failure is not simply due to regular wear and tear. I have used First Lite gear dating back to 2015, and have not yet had a reason to send any items in for warranty issues.
Takeaways: First Lite Uncompahgre Foundry Jacket
Here are my takeaways after putting this jacket through the ringer for an entire season:
First Lite Uncompahgre Foundry Jacket Strengths:
- Extremely durable
- Waterproof, windproof, and insulated
- Loaded with features for additional comfort
- Versatile and can be used for a wide range of outdoor pursuits
- Excellent fit for layering underneath
First Lite Uncompahgre Foundry Jacket Weaknesses:
- Weight – Not the lightest jacket in First Lite’s lineup at 34.5oz
- The magnets of the dump pockets are not excessively strong. I did have my phone fall out once when leaning over to pick up my Exo Mountain Gear pack. The dump pockets are better suited for items that are not dense (hats, gloves, etc).
- Price Point – $340.00 retail
Conclusion: First Lite Uncompahgre Jacket Review
The 2024 season was arguably my most adventurous ever. I was fortunate to spend a ton of time outdoors backpacking, fishing, and hunting. A multitude of memories were made this season, including backpack fishing Colorado alpine lakes with friends, completing my first ever Ivory Holsters “Death Hike” of ~36 mountain miles in ~32 hours, and solo archery and rifle kills on bull elk in Idaho and my home state of Colorado with each being on an OTC/general tag. The First Lite Uncompahgre Jacket was a welcome addition to my kit and has truly “leveled up” technical hunting apparel.
There are obviously many factors that go in to having a successful and enjoyable experience in the backcountry. Having functional, versatile, and high-quality gear like the Uncompahgre Foundry Jacket eliminates one variable and made a huge difference in keeping me warm, dry, and out in the field longer. If you’re in the market for a durable, wind-proof and insulated “do-it-all” western hunting jacket, check out the First Lite Uncompahgre Foundry.
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