The first sip brought instant refreshment: it's clean and crisp with a bracing noble hop bitterness, all pale green celery and leek. The soft lager malt, which I'd regard as more of a Kölsch hallmark than the hops, stands politely but determinedly at the rear. And it's the clear yellow colour that any Düsseldorfer would recognise as the correct shade of baby pee.
And then the niggle arrived. At first I thought it was a flaw: a bleachy, disinfectant tang, perhaps understandable in a beer like this where there's nowhere for it to hide. But my other half couldn't taste it, and later, indoors, I opened a second bottle to explore it further. It was still there but I reckon it's actually a feature rather than a bug: a function of the hop bitterness that just comes across as slightly chlorinated in my perception. I'm reasonably sure that your mileage will vary. For that gorgeous fresh first mouthful I'd still be willing to give it another chance.