Here We Go 'Round The Mulberry Bush - Van Dieman Brewing
Inviting wild microbes to grow in your beer seems to go against the grain of most modern brewing practices, but that is precisely the point of spontaneous or wild fermented beer.
Van Dieman brewing have established their niche with Australian spontaneous ales. These beers are Australia’s version of the Lambic ales that have been around for hundreds of years. Lambics are known for their sourness and funky characteristics and are exclusive only to the Zenne valley in Belgium due to the unique wild and native yeasts and bacteria for the region. Brewer Will Tatchell respects and pays homage to these traditional beers by creating his own spontaneous ales, produced from ingredients grown on his farm in Evandale in Northern Tasmania.
I tasted my first ever mulberry on a farm in Tassie in earlier this year and the juicy sweet fruit instantly became my number one favourite, so when I saw Van Dieman release a mulberry fruited spontaneous ale I knew I had to get my hands on it!
Here We Go ‘Round The Mulberry Bush is a part of Van Dieman’s The Wilderness Project range of Spontaneously fermented coolship beers. A spontaneous ale with mulberries, produced with 100% farm-grown and processed ingredients. This beer is a beautiful vibrant rose colour in the glass with gentle carbonation, minimal head and dry finish. The spontaneous yeasts provide an addictively tart acidity and straw-like notes while the mulberries add jam like aromas with true-to-the-fruit tart berry flavours.
While the microbial introductions are spontaneous and ending up with this delicious beer may seem like magic, the overall method and the way Will yields this brew has science involved in every step.
Will choses farm grown ale malts as well as raw barley and wheat to make the sugar rich wort which are boiled with farm grown and aged hops. The aging of the hops reduces the levels of alpha acids (the bittering compounds) to ensure the delicate flavours produced by the wild yeasts and fruit are not overshadowed by any strong hop flavours. It is still important to add hops as the hops provide the anti-microbial preservatives, to slow and control the growth of the wild yeasts to bring out key character differences. The sweet wort is then transferred to a coolship, which is a large shallow metal tank, open to the environment for 8-24hrs. This allows the wort to cool slowly as bacteria and yeasts from the farm air fall in. The liquid, now host to thousands of microbes, is transferred to oak barrels to let nature do its thing: fermentation. This beer was kept in the oak barrels for 2 years, during this time a menagerie of microorganisms eat up all different sugars and produce an array of different flavours. These barrels allow oxygen permeability for the long fermentation process, as well as potentially introduce more microorganisms and flavours from the wood.
When beer is brewed commercially it is usually brewed with a “single culture” of yeast – usually Saccharomyces cerevisiae (ales) or Saccharomyces pastorianus (lager). In wild fermented or spontaneous Lambic-style beers many different yeast and bacterial strains will colonize the liquid, and then it is a successive battle of the fittest for the fermentation period. Over this time the flavours and microbial composition will vary hugely. Will Tatchell says time is your friend here. Early stages of fermentation produce aroma and flavour precursors as well as unfavourable by-products which will be further broken down and metabolised by other microbes. As the yeasts produce ethanol and acids lowering the pH, unfavourable, alcohol-intolerant and acid-intolerant microbes will die off until you are left with just the lactic acid bacteria like Pediococcus and Lactobacillus, as well as the characteristic Brettanomyces, to produce the majority of the acidity we love in this style of beer. Acetic acid bacteria are able to convert ethanol to acetic acid, which further increases the sour flavour.
Adding fruit towards the end of the maturation of the beer adds flavour, colour and aroma while inducing a secondary fermentation from the fruits sugars and introducing more wild yeasts and bacteria from the skins of the fruit. For Here We Go ‘Round The Mulberry Bush the mulberries are left in for 8 months, leaving very little residual sweetness from the fruit itself, enhancing the tart berry flavours and producing a delightful pomegranate gem coloured beer.
The intriguingly complex, dynamic flavour spectrum meant I couldn’t help but keep picking the glass back up for another sip. Spontaneous beers truly provide context of time, place and culture and Van Dieman are sharing a piece of Everton farm in every sense with this beer.