Somebody kelp me

How seaweed is bringing surprising flavours to beer and helping sustainability efforts, too, writes Ella Buchan

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The potential of seaweed has been bobbing about under the surface for quite some time. Occasionally, a story drifts ashore to demonstrate its versatility and eco credentials. It can be used as a substitute for gelatine and sugar, as animal feed, to fertilise crops, and in cosmetics. Work is underway to assess its viability as biomass for fuel and even to create a biodegradable alternative to plastic.

So it was only a matter of time before brewers began tapping into this hero ingredient. Craft breweries in the US, where the market for sour and gose styles is arguably a few years ahead of the UK, have been experimenting with adding seaweed and even using seawater as a base for ales.

Now a handful of companies across the UK are trying their own, using kelp foraged along the coastlines to bring qualities of salinity, umami and malty sweetness. Devotees insist this isn’t a gimmicky or novelty ingredient. Used carefully, balanced with other ingredients and sourced sustainably, it can impart brews with unique local characteristics, create more body, and carry – or help to balance – other flavours.

Phil Saltonstall, founder of Brass Castle Brewery in Malton, North Yorkshire, points out that, while seaweed as a prominent ingredient is a relatively new trend, it’s long been used in brewing. Copper finings, added to help coagulate the protein and prevent haziness, are derived from seaweed. “It's actually had a role to play in the production of most beers,” he says.

Brass Castle’s seaweed adventures were sparked by their proximity to SeaGrown in Scarborough, just 25 miles east on the North Yorkshire coast. SeaGrown, founded in 2018, establishes and maintains beds of seaweed in the North Sea. Its aim is that the resulting marine farm, which requires only sunlight and seawater to thrive, can sustainably supply a myriad of industries from plastics to pharmaceuticals.

The brewery sourced dried sugar kelp from SeaGrown and, after gathering tips from Marshall Wharf Brewery in Belfast, Maine about their experience brewing with seaweed, opted for a red IPA to showcase the umami notes. Their 6.5% Meet Me Underwater proved popular and they’re now experimenting with other styles.

“Meet Me Underwater is not especially salty, but the seaweed note is there in that enhanced umami fullness,” says Phil. “We’re now looking forward to brewing a follow-up pale ale and to see if we can make that work with more hop punch and at a lower ABV.”

Lucy and Stephen, Futtle Brewing. PHOTO: Caroline Trotter

At Futtle, which perches on the coast of the East Neuk of Fife around an hour from Edinburgh, Lucy Hine and her partner Stephen Marshall specialise in brewing with locally foraged ingredients for seasonal and terroir-driven ales. Seaweed, then, was a natural progression from gorse flowers, yarrow and horse parsley.

“We gather small amounts at a time from the stretch of coastline outside the brewery [with the landowner’s permission],” says Lucy. “We take scissors and a bucket out on the rocks at low tide and gather from many different locations so we aren’t unduly disturbing the natural ecosystems that exist out on these rocks.”

It sounds idyllic, though achieving the right balance of textures and flavours isn’t easy.

“We have had to do a lot of experimentation,” she explains. “Some varieties that are very accessible and sound lovely actually end up turning fishy in drinks. So spending time getting to know many different varieties of seaweed has taken time and cost us a lot in batches that just haven’t worked.”

What it can bring is natural clarity, “minerality and bigger body”. “Sometimes the minerality can just feel salty, which is what we were looking for in our Gose, but very often it creates a kind of savoury background that gives the beer more depth of flavour. It definitely effects the body of the beer, giving it more weight in the mouth,” adds Lucy.

Chris and Sharon Bannister founded small-batch brewery Caffle in Llawhaden, Pembrokeshire with a similar ethos of celebrating local flavours. Having already produced nettle beer and blackcurrant stout, they were encouraged to create their Seaweed Ale by chef-forager Matt Powell. The amber ale, made with foraged kelp, is the result of a collaboration between Caffle and Matt’s company, Fishing and Foraging Wales. 

“Seaweed is used as an alternative to late hop additions to the beer,” explains Chris. “A method of air drying, dehydrating and conditioning the kelp allows the unique flavours to be released into the copper during the brewing process.”

Those unique aromas include liquorice, molasses and dark toffee, with a touch (Chris reckons) of “fresh walk on the beach”. A pinch of salinity and those background umami notes slice through any sweetness and create a particularly refreshing ale.

Sustainability is a factor, too; local foraging means a lower (or zero) carbon footprint, though seaweed’s anti-pollution role means it’s crucial this natural resource isn’t depleted. The team at Caffle is careful to gather small quantities from different sites along the miles of Pembrokeshire coastline on the doorstep. The kelp is dried in a shed built for the purpose, and Chris has also experimented with a pale ale “with favourable results”. 

Wild Beer, in Shepton Mallet, Somerset, gets its seaweed from a farm in the Mediterranean Sea. It’s added during the boil for its Yokai session ale, which also uses citrus fruit yuzu and Sichuan peppercorns for a “floral and complex spicy aroma”.


“In my experience, using seaweed helps create a good base for beers that have funky or unusual ingredients,” says co-founder Brett Ellis, whose brewing style is influenced by his time as a chef in a Hawaiian fusion restaurant in Los Angeles. “Too much seaweed just tastes thick, rich and green but when you get the right balance it can give the perfect umami flavour.”

At Williams Bros. Brewing in Alloa, Clackmannanshire, seasonal, small-batch dark ale Kelpie was inspired by the Scottish coastal alehouses of the past. Up until around the mid-19th century, malted barley was grown in fields fertilised by seaweed. “This gave the barley a very specific flavour which we recreate by the inclusion of fresh seaweed in the mash tun,” explains Chris Williams, who runs the family business with his uncle, Scott.

They use bladder wrack, foraged at low tide on the North Argyle coastline, and – after cleaning away sand, pebbles and any other sea-related stuff – shred the brown seaweed and add it to the mash along with the grains. The resulting ale has aromas of “fresh Scottish sea breeze, chocolate and a distinctive malty texture”.

“As it is from the sea it does have a saltiness to it, but it’s rich in minerals which are far more complex and layered than just adding salt to a beer,” explains Chris. “We have found its savoury character does suit darker malts, although Oud Beersel [in Flemish Brabant, Belgium] have also used it to great effect in lambic too.”

Seaweed’s future in brewing may largely be determined by the issue of supply. If SeaGrown’s efforts in marine agriculture continue to thrive and perhaps inspire other offshore farms, the wider availability of sustainably grown kelp might just spark a bigger trend.

For now, Lucy at Futtle reckons seaweed will continue to be seen as an “experimental” ingredient. “It’s completely disappeared from our diets over the last couple of hundred years and it looks like that won’t be changing any time soon,” she says.

Its potential to add interesting aromas, though, is huge. “It’s versatile,” adds Lucy, “so if you use with a light touch, you could use in pretty much anything.”

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