I went inside GORE-TEX's German testing labs to find out why waterproof jackets cost so much

There's something slightly unsettling about watching a perfectly good outdoor jacket being subjected to the kind of weather most people would actively try to avoid, especially when you're standing comfortably indoors while the garment gets absolutely drenched.

Yet that's precisely what I found myself doing during a recent visit to GORE-TEX's facilities in Putzbrunn, near Munich, where the company was celebrating 50 years of its waterproof fabrics and offering a rare glimpse into the processes behind one of the outdoor industry's most recognisable technologies.

Having tested countless waterproof jackets over the years, I was keen to understand why products bearing the famous black diamond logo often cost more, especially when competing waterproof technologies promise similar levels of protection for considerably less money.

After spending time around machines designed to simulate rain, wind, abrasion and years of wear, I came away with a different appreciation for GORE-TEX.

Turns out, the brand’s involvement in the development of waterproof clothing extends well beyond supplying the membrane that sits between layers of fabric.

Making it rain

Most outdoor enthusiasts will be familiar with the basic principle behind the iconic GORE-TEX membrane. It’s designed to prevent liquid water from passing through while allowing water vapour generated by your body to escape.

It's an ingenious concept, but understanding how the membrane works doesn't necessarily explain how a jacket will perform when the weather turns unpleasant.

When you factor in seams, zips, pockets and other construction details that can compromise an otherwise perfectly waterproof material, you realise how complicated it is to design a waterproof shell.

That's where GORE-TEX's testing facilities come into play, with dedicated equipment that subjects fabrics and finished garments to controlled rainfall, wind and other environmental conditions to expose potential weaknesses before products reach consumers.

During the visit, we were shown the company's rain-testing facilities, where garments can be assessed under simulated weather conditions.

For example, the infamous Rain Tower lets GORE-TEX test how a complete garment behaves when exposed to water, while also helping to determine whether the design provides the level of protection expected of a product carrying the company's branding.

Watching the tests, I couldn’t help but feel sorry for the mannequin inside the tower, with rain coming in its direction from every angle. After the wet-weather protocol, we went into the tower to see if the GORE-TEX jacket and trousers kept moisture off the mannequin’s base layers.

As expected, there wasn’t as much as a drop of water inside the shell. However, the more we learned about the testing process, and as I was beginning to appreciate, the membrane alone doesn't explain those differences.

Waterproof doesn't necessarily mean comfortable

Another part of the tour showed how GORE-TEX evaluates material performance beyond its ability to keep rain out, including tests that measure resistance to water pressure, wind penetration and moisture vapour movement.

One demonstration involved hydrostatic pressure, which measures how much pressure a material can withstand before water begins to penetrate it. We were told that GORE-TEX laminates must meet a minimum waterproofness requirement equivalent to a 28-metre (28,000 mm) column of water.

That's an impressive figure, although hydrostatic head is only one measure of performance, and a jacket with an exceptionally high waterproof rating won't necessarily be more comfortable or better suited to your needs than one with a lower figure.

Wind resistance is another consideration, and not surprisingly, GORE-TEX has a machine that tests its apparel’s ability to protect its wearers from the gust. One lucky participant got to try it, and even though the demonstration wasn’t as spectacular as the Rain Tower, it showed just how broad the in-house research process is.

Manufacturers must balance keeping external moisture out and allowing internal moisture vapour to escape, something that becomes particularly noticeable when hiking uphill or running.

GORE-TEX uses different testing methods to evaluate these characteristics and determine whether materials suit their intended applications, recognising that the ideal fabric for a lightweight running jacket isn't necessarily the same as the one you'd want for a mountaineering shell designed to withstand years of demanding use.

The machines that try to destroy your jacket

While keeping water out when a jacket is brand new is obviously important, maintaining that performance after months or years of regular use presents an entirely different challenge, which is where some of the more elaborate testing equipment comes into its own.

We saw machines designed to repeatedly rub, flex and stress materials, replicating the sort of punishment outdoor clothing endures in everyday use, from backpack straps rubbing against a jacket's shoulders to fabric subjected to repeated movement.

GORE-TEX likes to go the extra mile when it comes to destroying its products. For example, the company added little bumps to the surface of the panel on which the fabric sits to imitate the uneven surface jackets and trousers might rub against in real-world scenarios.

This puts more pressure on the fabric, as it focuses the stress in more concentrated areas. It might sound cruel, but this approach helps assess how materials cope with prolonged friction, while other tests examine how laminates and their individual components respond to mechanical stress.

The same principle applies to footwear, where testing becomes even more elaborate due to the constant flexing, pressure and movement that shoes and boots experience during walking.

We were shown machines that repeatedly bend footwear to simulate extended use, alongside equipment designed to identify potential water ingress, including one particularly memorable setup that involved testing footwear with water inside it and using centrifugal force to reveal weaknesses.

It's the sort of behind-the-scenes testing most customers will never encounter, yet it demonstrates why producing reliable waterproof footwear involves considerably more than simply incorporating a membrane into an existing shoe design.

GORE-TEX doesn't just make the fabric

Perhaps the biggest revelation of the visit wasn't any individual machine, but how deeply GORE-TEX remains involved in the development and manufacturing of products that carry its name.

I always thought of the company as a material supplier, with outdoor brands designing their own jackets, selecting a suitable GORE-TEX fabric and incorporating it into the finished garment.

In reality, the relationship is considerably more involved, with GORE-TEX working alongside manufacturing partners and establishing requirements that extend beyond the membrane itself to include construction methods, production processes and testing.

These requirements aren't necessarily identical across every product category, either, because a lightweight lifestyle jacket, a technical mountaineering shell and a waterproof hiking boot are designed for different environments and must withstand different forms of wear.

Alongside laboratory testing, the company also conducts field trials to understand how products behave outside controlled environments.

During the visit, we heard about testing programmes involving substantial numbers of garments being used in demanding conditions, allowing the company to assess how different materials and construction techniques perform over time.

These processes create a quality-control system that goes beyond simply supplying a roll of waterproof fabric, even if much of that work remains invisible to the person browsing jackets in an outdoor retailer.

So, does that justify the price?

After touring the facilities, I have a better understanding of why GORE-TEX products can be expensive, though the answer is more complicated than simply pointing to the cost of developing and manufacturing a waterproof membrane.

The familiar branding represents a broader system of material development, laboratory testing, manufacturing requirements and quality assurance, all of which require investment and contribute to the performance expectations associated with GORE-TEX products.

That doesn't mean every jacket bearing the logo is automatically worth its asking price, of course, because factors such as fit, comfort, features and suitability for your intended activities remain just as important when deciding which waterproof shell to buy.

Nor does it mean competing waterproof technologies can't perform extremely well, or that GORE-TEX is the only company investing in rigorous testing and product development.

Nevertheless, the visit changed how I think about the famous black diamond logo, particularly when comparing jackets that appear relatively similar on paper but occupy very different price brackets.

It's easy to focus on waterproof ratings, fabric construction and other technical specifications when shopping for outdoor clothing, but having seen what happens behind the scenes, I'd argue that the less visible aspects of product development deserve just as much consideration.

After all, keeping you dry during the first downpour is one thing, but ensuring that a jacket continues to perform after repeated use, washing and exposure to the elements is a considerably more demanding proposition – one that GORE-TEX clearly takes very seriously.