This January sees the launch of one of our core beers into cask for the first time. First brewed in 2018, Green Mountain has established itself as a firm favourite among drinkers due to its hoppy flavour and hazy appearance. Previously only available in keg and 330ml cans, we use Maris Otter, Wheat Malt and a touch of Caramalt to give it a slight golden hue. The wheat malt, high in protein, gives a soft pillowy head to the beer and carries the fruity, citrus aroma of Citra, Simcoe, Galaxy, Mosaic and Amarillo hops.
A key feature of Green Mountain is that most of the hops are added directly into the fermenting vessel during fermentation. When mixed with yeast, this allows something called ‘Biotransformation’ to occur. Terpenoids, thiols and other aromatic compounds are transformed by the yeast into other, longer lasting aromatic compounds, like Citronellol. This is what brought us on to a cask version, as we are big advocates of a full cask conditioning process and this can let biotransformation occur in the cask.
Cask conditioning is where beer is racked into casks with some excess sugar for secondary fermentation to occur. This enhances the flavour and brings much need carbonation to the beer but there is an art to cellaring beer properly, achieving the right amount of carbonation and serving the beer when it is at its peak. An experienced cellar-person can make or break a cask beer and that’s why many pubs gain such a reputation for great cask beer.
In bringing Green Mountain to cask we’re allowing the biotransformation to occur alongside the traditional cask conditioning process. Melding old with new is a Thornbridge speciality! IPA is all about freshness of hop flavour, aroma and mouthfeel – what’s fresher than a pint of cask beer? We have also made the decision to retain the hazy appearance in cask; the extra proteins that create the haze bring something extra to the mouthfeel of the beer. But don’t worry, the majority of the yeast will still have settled out - it’s mainly protein-polyphenol complexes that give the beer its hazy appearance.
Green Mountain in cask gives a hit of hops without the gas in a live beer, traditionally cellared to bring modern beer flavours and styles to what British breweries do best: a pint of cask ale in a brilliantly run public house.
Written by Ben Wood, Technical Brewer