Sowans and swats - forgotton Scottish oat ferments

Sowans (apparently pronounced 'soo-an') from the gaelic subhan or 'sughan' is a traditional Scottish oat fermentation that produces both a creamy lacto-fermented porridge (sowans), and a tangy probiotic drink (swats or strunt). The sowans can be kept either dry as a starch or in a moist form for months.

sowans in the making

source

Once the oats were dried and ground, crofters and others having given the oats to the mill would get back not only the ground oats but also a bag of “sids”. These would be the oat husks (I guess we’d call this oat bran today) with little bits of the kernel still attached to them. Not wanting this to go to waste people would make Sowans out of them

Basically the process involves adding warm water to the sids and leaving them to ferment for about a week, the husks are then sieved out (and e.g. fed to chickens) and the liquid drunk fresh as a milk substitute or left to settle - a clear yellowish liquid (swats) then forms above a layer of starch (the sowans). The liquid can be poured off or drunk, and the sowans used in various ways: as a sort of porridge meal, to make a flummery type pudding, as a liquid ingredient in scones, or as a tangy oat 'milk'.

making sowans porridge

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Apparently the taste of the raw sowans is sour to a modern palate, but full of good probiotic bacteria and easier to digest nutrients. Although the pro biotic bacteria are killed if the sowans are cooked into porridge, the starch remains a good probiotic and improves absorption of minerals in the gut.

sowans pudding

source

Apparently there was a similar process in Wales (and in Ireland) and a related one in Russia called kissel: which involved fermenting oats with a slice of rye bread. This was adapted by Dr Vladimir Izotov to make 'Russian Miracle Elixir' also including kefir, to treat his tick-borne encephalitis ref: https://www.beetsandbones.com/fermented-oat-kissel/

Sources / further reading:
https://cailleachs-herbarium.com/2018/03/sowens-fermented-oats-scottish-traditional-food-recipe/
https://britishfoodhistory.com/2022/10/06/to-make-sowans/
https://www.aboutorkney.com/the-wey-hid-wis/sowans/
https://rootsinfood.wordpress.com/2017/01/30/sowans-the-fermented-oat-food/comment-page-1/
Marian McNeill’s book ‘The Scots Kitchen’, a 1920s cookbook about traditional Scottish food and it’s history
https://www.uhi.ac.uk/en/research-enterprise/cultural/institute-for-northern-studies/blogs--exhibitions/mimirs-well-articles/an-experiment-with-sids-and-sooans.html
https://www.duchas.ie/en/cbes/4428244/4388005/4510317
https://tohercore.com/fermented-sourdough-oats/

I merged your stuff with the following thread. I hope that is okay by you.

I am also intrigued by sowan. I'm doing an initial experiments with what I have to hand: rolled oats, soya yoghurt & tap water.  Its probably too cold at the moment too, but let's see ..

Success! A smell like rising wheat bread dough, and a lovely tang to both swans and swats.  

But took a full 5 days to reach that stage here in early winter even in a warm (centrally heated a couple of hours per day) room.

Here's the resulting swans, with biofilm.

Ac Baker,
I have merged your topic into this topic. I hope that helps.

Thanks for sharing Ac - It seems that the temperature they fermented at might have been cooler, as many of the reports suggest if it is left much more than a week the result can be rather unpalatable, probably 4 -5 days is about right in a modern house. If it is too warm then undesirable moulds may also take hold, although removing the crust and discarding was an authentic action too!

I think if you are using commercial oats then adding a starter as you did is probably a wise move - once you've got it going well adding some from a previous batch is probably te easiest. Fresh 'sids' would have natural yeasts and bacteria present to get the ferment started, but milled oats are usually heat treated for improved storage life.

Did you try it as an 'oat milk' at all? How was it?