Siobhan Buchanan updates us on Siren’s nitro adventures


Siren has long been at the forefront of experimenting with nitrogen to give its beer effervescence, rather than the more usual carbon dioxide. While nitrogenated beers have been around for decades, its use has generally been limited to a narrow set of styles; the imperceptibly tiny bubbles and ultra-creamy mouthfeel of nitrogen are a million miles from the tongue-prickling fizz of CO2, so the technique was deemed most suitable for luxurious stouts and porters. This has all changed in recent years though, as craft drinkers have developed a broader appreciation for all things velvety and smooth, notably with lactose-laden milkshake IPAs and oat-heavy murk creeping onto taproom boards across the land. 

When I last spoke to Siren’s Andy Nolan, the brewery had just released a tasting pack of its new nitro beers side-by-side with the core original carbonated beers, including its porter, red IPA and breakfast stout. The past six months have seen the experiments continue, with the release of a nitro version of Pompelmocello, its grapefruit sour, which has been a big hit. The nitro gas gives the beer more body, so it becomes almost sorbet-like in consistency, and the acidity and sourness of the grapefruit cut through the smoothness of the beer. 

Andy comments that one of the perceived downsides of nitro beers is that: “you can subdue the aroma, because the lovely thick head on top makes it difficult for the aroma to get out of the glass, whereas carbonation would be pushing that aroma out. One of our theories was that because Pompelmocello has loads of grapefruit juice and zest in it, and a load of punchy hops, that this would help the beer release some nice aromas on the nose still. It came out great, so there’s definitely more things like that to come in the future.” 

We discuss how, in a way, nitro beer is slightly akin to drinking cask beer; both are smooth and soft and, especially when cask beer is poured using a sparkler, they both have a creamy head.

“Some cask beer drinkers and real ale lovers might not like the idea of drinking beer from a can, but the first thing that came to mind when we were trying these beers was how similar the experience is,” comments Andy. This cask-like experience is reinforced when using the proper ‘inverted’ or ‘hard’ pour technique for serving nitrogenated beer; the bottle or can is opened and immediately placed vertically upside down in the glass causing the beer to glug out dangerously. The dissolved nitrogen is activated, and rolls of creamy bubbles rise slowly to the head of the glass as the beer clears. It’s quite beautiful.

Since Andy and I last spoke, Siren has also bought a pub, which he is clearly very excited about. “It’s a traditional country pub, quite close to the brewery, in a beautiful listed building. Roaring fires in the winter, country walks in the summer, that sort of thing. It gave us the excuse to brew a best bitter, which we have never done before, and in turn, that gave us a chance to try a best bitter in a nitro can. The beer is called Memento, and it’s a pretty traditional recipe, but with a nice bit of Cascade in the dry hop which gives it a citrusy bitterness. It came out awesome, and is a continuation of the theme of ‘what can we do to bring the cask experience home, and can nitro bridge that gap?' We’re struggling to keep it in the brew plan but we hope to make it a consistent thing, and we would love to have it pouring at the pub permanently.

 “We also did an ESB as part of our Project Barista series [which was also all on nitro this year]. The ESB is modelled on a very classic recipe - two of our brew team have worked for big traditional real ale breweries in the past - but we added coffee and hazelnut, with the idea that a bit of acidity from the coffee would help lift the beer and make up for the lack of carbonic bite, and the hazelnut would complement the nuttiness of the malts. The aim of the Project Barista series isn’t to make beer taste like coffee, but to try and enhance flavours that are already there and see how things work together. It’s interesting because after years of not touching these kind of recipes, we have in quick succession brought out a best bitter and an ESB. I don’t think we would have done that without the nitro capabilities to be honest, it’s come from this idea of ‘cask in a can’.”

The biggest news on the nitro front is that Siren has just done its first trial of a straight IPA, nitrogenated in cans. This one is an advent calendar exclusive, so if you get to try it, you’re lucky. Andy says: “we have a theory that because hazy IPAs have a lot of proteins in them which give them a full body, that they should suit nitro. The bit that you want to counteract is the subdued aroma, which could be a downside, but we added some punchy hops to help with that, and it has turned out wonderfully.

“We aren’t afraid to split the crowd and do experimental things to see if they work, so whatever happens we will definitely be learning from it.” 


Midnight Merriment: The idea behind Midnight Merriment is to get as much body and flavour as possible into a lower-ABV stout. To achieve this, lactose is replaced by vegan-friendly oats and wheat, and the beer is aged on oak chips from a bourbon barrel previously used to age maple syrup. The flavour is full-on maple syrup, oak, roasty toasty malts, and chocolate, with this flavour profile also translating to the aroma. 

In with the Neo: In with the Neo, a session IPA, is a showcase of descendants of Neomexicanus hops, a subspecies of hops that grow in New Mexico in the US, which have only recently been harnessed for commercial use. Through experimentation and cross-pollination of these hops, we now have hops such as Tallus, Sabro and El Dorado, which are showcased in In with the Neo. Expect juicy pineapple aromas, tropical flavours and pithy grapefruit bitterness. 

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