A few years ago, I was sat chatting with Thornbridge Co Founder and Owner, Simon Webster, about the Thornbridge portfolio of beers and he mentioned how the one thing I’d never brewed was a special strong, dark beer. In the past, Thornbridge has produced some very famous examples such as Saint Petersburg, Heather Honey Stout and Bracia so Simon threw down the gauntlet and said it was about time I came up with my own – the remit was to brew the best strong dark beer I could.
On a trip to the US last year, I took time out to taste as many big dark beers as possible, bringing back in bottle any that I thought had something special about them, including Firestone Walker’s Parabola, Bourbon County and Alesmith’s Speedway Stout. We did tastings back at the brewery and also dissected them in the laboratory, basically pulling them apart until we had the measure of what made them great beers. In the end, I decided to brew a very strong bourbon barrel-aged imperial stout – an immense beer, perfect for the fireside and something really special.
These beers are very much about the malt and I cannot stress enough how important it is to get the right blend of grist for a project such as this. It’s not something you can stumble upon and I put a good bit of work into getting it just right, so we had the body and mouthfeel as I wanted. This beer was always going to be an all-malt brew, so we loaded the mash kettle up to its absolute limits, collected the first runnings and started the same process again, so the beer was suitably strong. Primary fermentation at such a high original gravity was always going to be something of a challenge, so we used a blend of our British yeast strain and the California ale strain for the perfect flavour, as well as a special high gravity yeast to help attenuate the beer accordingly.
The barrels weren’t just going to be anything we could get our hands on or something second hand we just had lying around. These are better made into planters! I was lucky enough to source some freshly-emptied Jim Beam bourbon casks in the US and had them imported in a container. After a couple of weeks maturation in steel, we then filled the barrels as carefully as possible, keeping them well away from our other barrel ageing projects that are full of wild yeast and bacteria.
Ageing beer in bourbon is a different animal to barrel aged sours – we’re not measuring the pH or acidity and there’s no gravity drop to watch out for, but there are some similarities. There is an optimum temperature for ageing, plus we needed to taste the beer regularly as we sought to identify when the beer was ready. What we were looking for was the correct amount of oakiness from the barrel, the right amount of vanilla and also a softening of the beer itself, so the beer becomes silky smooth and takes on a luxuriousness. There is a tipping point with bourbon barrel ageing, where the beer can take on a soy sauce-like flavour, which I’d noticed in the US and thankfully we managed to avoid. In the end it took about 8 months of ageing until it was just perfect and we packaged it into bottles straight away. For me it’s a formidable beer that really hits all the right buttons; the perfect body, mouthfeel and enjoyment and I have stashed some for Christmas already.
All that was left was an appropriate name - I hope you can understand that given the challenge set to me by Simon, I though the name ‘Necessary Evil’ was most apt!