Zak Avery: A creamy stout, with soft coffee flavours and an earthy finish... so why have sales gone flat?

Surely there can't be a more iconic beer in the world than draught Guinness. A pint of the black stuff, topped with its trademark creamy white nitrogenated head, has graced our bars for more than half a century. The beer used to be served in the same manner as all other beers, originally from cask, then moving to carbon dioxide pressure, before the introduction of nitrogen to the mix. Nitrogen gives Guinness its fine, creamy texture, and means the beer is perceived as being less gassy and smoother by drinkers.

And it's an icon for a reason. Not only does it look great, but it tastes pretty good too. The smooth creamy stout, shot through with soft coffee flavours and finishing pleasantly dry and slightly earthy, is a good standby pint for beer aficionados who find themselves in a pub with a less-than-ideal beer selection. If you've never tried it, you'll be surprised to learn that it's nowhere near as full-flavoured as it looks, and if you've ever enjoyed coffee or dark chocolate, then you have a palate equipped to enjoy any stout, Guinness included.

And the draught product is just the start. There are two other variants that are a little harder to find, but perhaps more indicative of how Guinness got its reputation as a grown-up's drink. Guinness Foreign Extra (7.5%abv) and Special Export (8%abv) are both full-bodied and rich, with a pronounced espresso-like bitterness and some grassy hop character in the finish.

So why would such an icon appear to be losing its foothold in the market? As a nation, our drinking habits have changed radically over the last decade. There has been a trend towards sweeter drinks, both with so-called alcopops and the revitalisation of the cider category. Real ale has also made inroads into the market, and as a category is now in better shape than it has ever been – truly, there is an ale for every palate and every occasion. Add to this the increase in drinking at home, and the fact that growth in premium bottled beers is greater than in any segment of the brewing industry.

But, worse of all, maybe Guinness has simply succumbed to the sort of fate that eventually befalls all icons: ubiquity, familiarity, and contempt. Perhaps the famous two-minute, two-stage pour needs updating: Guinness slushie, anyone?

Zak Avery is a beer blogger, a former winner of the British Guild of Beer Writers' Writer of the Year, and author of "500 Beers", Apple Press