It All Adds Up! The Day Beer and Maths Lovers Need to Know About

Very Rare Beer released on International Tau Day – June 28th

Thursday June 28th 2018 will see craft beer lovers and maths fanatics alike, rejoice across the globe as the annual release of a very rare beer, Key Lime Tau, is made available.

In its fourth year, Key Lime Tau is a collaboration between Cumbria’s Hawkshead Brewery and Crooked Stave Artisan Beer Project in Denver, Colorado, USA. The limited edition beer is a kettle-soured, lactose-infused golden ale, brewed with fresh lime zest and lemon grass, which gives the beer a biscuity taste and a strong lime flavour – just like a key lime pie.

As much thought has gone into the naming of the beer as it has into the taste. A play on the mathematical symbol Pi, Key Lime Tau is so called because of the doubling up – it’s a collaboration between the two brewers and has been brewed on both sides of the Atlantic. Mathematically Tau equates to 2 x Pi (3.142), what mathematicians deem the real circle constant, which is also the strength of the beer – 6.28% – and the price per bottle, £6.28.

On International Tau Day, June 28th, just 4,800 bottles will be available to buy from select craft beer retailers in the UK. Hawkshead Beer Hall will be the only place in the world to have its Key Lime Tau on cask and will be celebrating over the weekend with live music and an American-inspired food offering.

Hawkshead Brewery and Crooked Stave have brewed Key Lime Tau together, in the UK and the US, as well as brewing it independently. The two recipes vary slightly due to the yeast and the souring. Crooked Stave’s version of Key Lime Tau will also be available to taste at Hawkshead Brewery on Tau Day, so hardened beer aficionados can see if they can taste the difference in the brews.

Head brewer at Hawkshead, Matt Clarke, cultivates the Brewery’s own yeast, which can’t be replicated anywhere else which makes any Hawkshead brew impossible to copy. Matt sours the beer using a kettle souring technique.

Crooked Stave’s head brewer Chad Yakobsen is one of the world’s best known experts in brewing with Brettanomyces and so uses non-spore-forming yeast. Chad uses his wild fermented yeast strain to create the sourness too. So Key Lime Tau is a unique collaboration, which retains the personality of its two breweries.

Key Lime Tau was first brewed in collaboration with Crooked Stave in 2015 for the International Rainbow Project, a bringing together of independent craft brewers to nurture innovation and share best practice.

International Tau Day itself is a global institution, with the Key Lime Tau brew being just one of the many ways, including limited edition art, branded clothing and discussions and events, that fans will be embracing to celebrate this mathematical symbol.

Set a reminder to buy online at when Key Lime Tau stock is released on June 28th

About Hawkshead Brewery

Hawkshead Brewery, cutting edge brewers of bold, innovative beers, was founded in 2002 at Hawkshead in the heart of the English Lake District. In 2006 the brewery moved across Windermere to larger premises at Staveley Mill Yard and a new tailor-made 20 barrel brewery. In early 2017, Halewood Wines & Spirits, the UK’s largest independent alcohol distributer and manufacturer, took ownership of Hawkshead Brewery and is funding the building of a new Krones AG turnkey brewery, due to open early summer 2018.

About Crooked Stave Artisan Beer Project

Founded in Denver, CO in late 2010 as an artisan beer project, Crooked Stave is the culmination of brewmaster and “Brettanomyces Guru” Chad Yakobson’s open source Master’s research, The Brettanomyces Project. Crooked Stave’s progressive approach to brewing blends science and art through creativity and passion. The resulting creations, most of which use Brettanomyces yeasts and mature in oak, are beers of extraordinary complexity.