Text: Orlando Addis, Photos: Wikimedia Commons and Orlando Addis
In a previous article we saw briefly how kelp ash was used to preserve seal meat. Here we will explore the technique in more detail. Meat was not the only food to be preserved in this way either: fish, cheese and eggs were all also kept by either burying them entirely in ashes or using seaweed ash in the place of salt. The burning of kelp for potash has a long tradition in Scotland and, prior to the invention of artificial fertilisers, was essential to the continued growing of crops in unforgiving soil.
The anti-microbial effect of the ash is three-fold. Firstly, the fine ashes absorb moisture, drying the surface of the food and preventing harmful bacteria from penetrating it. Secondly, the alkalinity of the ashes inhibits microbial growth by raising the pH. Thirdly, the salt content also reduces the water available to harmful bacteria.
On St. Kilda, Martin Martin observed that “burnt ashes of sea-ware preserves [sheep’s] cheese instead of salt” (1), while on North Uist “they are accustomed to salt their cheese with the ashes of barley straw” (2). On Jura seaweed ash was also used to preserve goat’s cheese (3). As alien as this may seem to us in Scotland today, unsurprising given the prevalence of modernisation over preserving traditional techniques , the use of ash in cheese making is actually quite common. In France goat cheeses are commonly coated or made with ash or charcoal while in the Veneto area of Italy there remains a tradition of cheeses called sottocenere or ‘under ashes’. The ash absorbs moisture helping to form a protective rind around the cheese, while also balancing the acidity of the cheese (4).
Back on St. Kilda, the locals, having risked life and limb scrambling over the cliffs with their prehensile toes (potentially even six of them according to legend!), would keep their hard-won wild fowl eggs in peat ash. This method of preserving eggs incredibly still occurs on Iceland. According to Magnus Nilsson (who describes a similar technique used on Iceland) “the alkalinity of the ash would act on the protein of the egg a bit like a thousand year-old egg in Asia, slowly curing it. At the same time the dryness of the ash would desiccate the egg still in its shell, making it possible to store the egg almost indefinitely.” (5). Whether or not the eggs were eaten raw or cooked on St. Kilda, Martin makes no mention, although he does note that they are “astringent to such as be not accustomed to eat them.”. No surprises there then.
There are several references from Orkney and the Western Islands to salting and drying seal and whale meat into ‘hams’ to preserve them, or salting and fermenting the meat otherwise. While this might also have been done with normal salt, on North Uist seaweed ash was also used when salt was not available. While on Bernera, just off the Isle of Lewis, they would use seaweed ash to salt wild sea-birds, keeping them in cow-hides (6). Using ash in preserving meat is actually nothing new or bizarre. Wood ash was once the starting point for making saltpetre, which has been used in ham and charcuterie making since the Middle Ages. In Umbria, Italy, there is a tradition of preserving salumi in the ashes from wood ovens (7). An old American preserving manual from 1918 even suggests that “ham and bacon may also be kept by placing the pieces on a layer of sifted ashes and covering with a thick layer of the same.” (8)
Finally, we come to fish. Mackerel to be precise, seasoned with seaweed ash “which preserves them for some time instead of salt.” (9) by the inhabitants of North Uist. Similarly to the salting of meat, the seaweed ash draws moisture away from the flesh of the fish, also forming a barrier to further microbial activity and the naturally high salt content of the seaweed ash again helps to prevent bacterial growth. While it preserves the mackerel for a time, you certainly couldn’t leave it there indefinitely without the fish becoming entirely desiccated. What is more, the highly soluble alkali in the ash would react with the water leeching out of the fish to form lye. Leave it like this and you would be well on the way to making Norwegian lutfisk. Whether or not the islanders left their fish to undergo such a transformation, Martin makes no mention.
So there you have it. Fish, meat, cheese and eggs, all preserved using the ashes from burnt seaweed. Seaweed was once a much more integral part of life in Scotland, not just on the Hebrides or remote St. Kilda, but all around the country. It was used for farming, as part of the diet, but also to preserve the food that kept them alive. Seaweed is now making something of a comeback into our diets, fuelled in part by a revived interest in foraging, but also by the growth in popularity of Japanese food and restaurants. And rightly so. Yet perhaps we still don’t realise just how important it once was in Scotland.
1. Martin Martin, A Description of the Western Islands of Scotland (London: Andrew Bell, 1703) p. 186
2. Ibid. p. 60
3. Alexander Fenton, A Compendium of Scottish Ethnology: Vol. 5 The Food of the Scots (Edinburgh: Birlinn Ltd, 2007) p.245
4. Venetoformaggi.it, (2016). Cenerentolo [online] Available at: http://www.bottegadellacarne.com/salumi- sotto-cenere.html [Accessed 22/11/2016]
5. Magnus Nilsson, The Nordic Cookbook (London & New York: Phaidon, 2015) p. 42
6. Martin (1703) p. 94
7. Mondodelgusto.it, (2016). Il Mondo dei Salumi: Prosciutto Crudo sotto cenere e sotto vinaccia. [online] Available at: http://www.mondodelgusto.it/notizie/9537/mondo-dei-salumi-prosciutto-crudo-sotto-cenere- sotto-vinaccia [Accessed 22/11/2016]
8. William V. Cruess, Home and Farm Preservation (New York: The MacMillan Company, 1918) p. 148
9. Martin (1703) p. 56