The CEO of Black Sheep Brewery has left the role, eight months after the UK-based brewer was purchased by UK investment firm Keystone Brewing Group.

Charlene Lyons has worked at the Riggwelter beer producer for nine years. A spokesperson for Keystone, formally Breal Group, said Lyons had left the Masham-based brewer to “pursue other interests”.

Keystone Brewing CEO Mark Williams will assume Lyons’ duties at the brewery. John Hunt – the former MD of Purity Brewing, a UK brewer acquired by Keystone in January – will assist Williams in the newly-created position of CFO at the parent group.

Since Keystone acquired Black Sheep Brewery, the investor has announced plans to invest £1m ($1.3m) into the brewery to increase production and storage.

Keystone is using Black Sheep Brewery’s facilities as a consolidated source of production for the London businesses Brick Brewery and Brew By Numbers it also acquired last year.

Founded in 1992, Black Sheep Brewery also produces vodka and gin under its namesake brand.

Breal announced earlier this week it would have the new name of Keystone Brewing Group. The buy-out house said the move was a reflection of its “commitment to innovation and growth” in the UK beer industry.

Keystone comprises the four UK breweries owned by Breal: Black Sheep Brewery, Purity Brewing, Brick Brewery and Brew by Numbers.

Breal either acquired the breweries upon their entry into administration or, in the case of Purity Brewing, when it was on the brink of administration.