A husband and wife duo on the Ayrshire coast are significantly expanding their efforts to revive a historic salt-making tradition, with the completion of a new, imposing graduation tower.
Gregorie and Whirly Marshall, founders of Blackthorn Salt, are celebrating the topping out of their second such structure, which is filled with thousands of blackthorn bushes.
This latest addition stands at an impressive 12 metres tall and 25 metres long, considerably larger than their initial eight-metre tower.
The innovative graduation towers operate by piping seawater to the top, allowing it to slowly trickle down through the dense network of thorns. The expansive surface area of the plants, combined with the bracing winds characteristic of the Ayrshire coastline, facilitates the evaporation of water, concentrating it into brine as it cycles through the tower. Salt is subsequently extracted from this concentrated brine.
The Marshalls’ site is unique in the UK in using this method, and examples of graduation towers around the world are rare.
They say their towers produce a “super-high” quality of salt in a more sustainable manner than other methods.
Their first tower began to yield salt on a regular basis in 2021, and they found the product was in demand.
Ms Marshall told the Press Association: “It’s been an incredible journey, the fact people in Scotland and around Britain love our salt and appreciate and understand why it’s produced the way it is – it’s phenomenal.”
Constructing the tower has taken about three years of on-and-off work, including laboriously fixing the blackthorn bushes in place.
The new tower has about 6,000 blackthorn bushes attached to it, which act as a “great washing line” to slowly evaporate the sea water.
Ms Marshall said: “They also impart flavour to it. The crystals have each of the five basic tastes.”
She said the graduation tower method is far more sustainable than other ways of creating salt as it requires very little energy for the water to evaporate.
Historically, the Ayrshire coast had a number of salt-panning sites which came and went throughout the centuries, some dating back to medieval times.
These often burned coal to heat sea water, producing rudimentary salt in pre-industrial times.
