Review: Castelli & Polartec's AirCore – a post-PFAS solution?

Ronan Mc Laughlin, Cor Vos

How often do you ride in the rain? Like proper rain, “bucketing it down,” as we’d say. If Castelli is right, not all that often, if at all, these days.

Castelli claims rider behaviour and weather are both changing. It says, "many of us now turn to indoor training when the heavens do open," while pointing to climate data that indicates that while the total volume of rainfall may remain consistent, it now occurs in more intense bursts over fewer days. Furthermore, Castelli says riders still reach for a proper rain cape when it does chuck it down and that average winter temperatures have increased significantly over the last two decades.

Consequently, it says these changes in the global climate have altered the performance requirements for winter cycling gear. Castelli claims riders now need breathability more than waterproofing and jackets that offer protection for passing showers but more importantly can handle higher intensity riding without causing the "boil in the bag" scenario that some membranes can.

Furthermore, Castelli now says the 10,000 mm water column test threshold a garment must pass to be labelled “waterproof” is an arbitrary number, pushed by the industry, and somewhat irrelevant for cycling. And they have a point: Water column testing is hydrostatic; a fabric rated at 10,000 mm can hold a column of water 10 metres high without leaking, a scenario that might matter for scuba diving, but not cycling.

Castelli claims the physical pressure exerted by rain is far lower, around 800 mm for light rain, and ~2,000 mm range for heavy rain, far lower than the headline-grabbing numbers found on many technical jackets. Thus, Castelli argues, what is actually needed is less waterproofing and more breathability.

That’s hardly a surprise from the brand so closely associated with wet-weather innovation and an extension of the philosophy it helped pioneer. Its Gabba was the original two-fingers up to the boil-in-the-bag waterproof shells that dominated cycling rainwear at the time, prioritising breathability, stretch, and real-world usability over waterproofness back in 2010. The original Perfetto was born out of the Gabba philosophy and today AirCore feels less like a radical departure and more like the logical next step in that thinking – a fabric that still distances itself from traditional waterproofing benchmarks and doubles down on moisture management and comfort as the primary objective.

The original Gabba elevated Castelli's perception as wet-weather experts.

Let’s be honest here, though. It seems awfully coincidental that Castelli suddenly decided to ditch waterproofing for better breathability shortly after the PFAS ban came into effect. Granted, they may have eventually gone that route, but their hands have been somewhat forced by the PFAS ban. Now that those toxic forever chemicals that proved so good at keeping rain out while maintaining breathability are out, the entire outdoor clothing industry faces a difficult decision.

Gone with them are the advancements in breathability and waterproofing that those nasty forever chemicals once made possible. As such, the clothing industry must decide if it wants breathability or waterproofness … it can no longer have both. But rather than agonising over how to find that balance, Castelli is now saying we had it wrong all along.

Performance vs. sustainability: the PFAS dilemmaAs bans on toxic “forever chemicals” take effect, brands admit the cycling industry has a long road ahead to clean up.Escape CollectiveSuvi Loponen

For some, the answer has been to retain waterproofing, even if it means sacrificing breathability. An understandable decision, given waterproofing is easy to market. Castelli, though, is taking the breathability route, and developed a new membrane in partnership with Polartec it says is more breathable and still plenty waterproof in practice, even if not technically waterproof.

If I am cynical, this could all be interpreted as clever narrative management – a way of presenting reduced waterproofing performance as progress rather than a decision forced upon clothing and membrane developers. The more generous interpretation, of course, is that Castelli is acknowledging something the industry has long danced around: that absolute waterproofness may have been the wrong objective for cyclists in the first place. Whether AirCore represents genuine advancement or well-executed adaptation depends on how these jackets perform out on the road.

What is AirCore?

Enter Polartec’s new AirCore membrane found in Castelli's new Perfetto RoS 3, a lightweight (153 g), versatile outer layer for cool, dry or damp conditions that Castelli once described as “the long sleeve Gabba," and its new Alpha 150, a heavier duty winter jacket (250 g) for when the temperatures drop.

AirCore is Polartec's answer to the post-PFAS problem; at the product presentation, Polartec representatives said that the technology originated in collaboration with Castelli, and Castelli and sibling brand Sportful have a five-year exclusive on using the membrane for cycling products.

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