Sour Milk: Lessons from Scandinavia

Viili, piimä, filmjölk, skyr – all obscure mouthfuls of rolling foreign vowels – that mean but one thing: cultured milk.  The Scandinavians, whose ill-tempered northern climate necessitates creative application of food preservation techniques, celebrate  soured milks and cultured dairy foods in a manner unparalleled by even the yogurt-loving people of the Caucasus. Indeed, they thrive on all manner of cultured and soured milks which are deeply ingrained into their culinary tradition and heritage, and from their undying love for wholesome, naturally soured milks we can all learn a lesson.

Scandinavia, though offering a remarkable plethora of cold-weathered vegetables, berries and other nourishing, suffers from severe, cold and dark winters characteristic of the north. No other word but harsh seems to better describe the challenges of a Scandinavian winter.  Indeed, it ought to for the word harsh itself is of Scandinavian origin, coming to the English language from the Norwegian word harsk.

The peoples of Scandinavia are masters of food preservation – techniques won through difficult and hard winters in which many bellies went hungry.  From necessity and practicality, a heritage of cultured, naturally fermented foods was born. They bring us gravlax, pickled herring, cheeses and sourdough breads, inlagda rödbetor (a type of pickled beet) and, of course, a wide variety of yogurts such as viili, piimä, filmjölk and skyr.

A 2008 study of over 82,000 Swedish men and women found that a high intake of cultured milk products seemed to lower the risk of developing bladder cancer.

Their love of cultured dairy foods is only fitting; after all, Sweden and Finland lead the world in milk consumption averaging three to four gallons of milk drunk for every man, woman and child in the country each month1. It’s only natural that such a milk-loving society would find unique and alternative ways to not only preserve, but also enjoy dairy beyond cold, frothy glasses of fresh milk.  Their time-honored love of fresh milk, cheeses and cultured dairy foods has undoubtedly benefited their health.  Indeed, the mere act of adding a starter culture to milk in effort to produce a yogurt not only increases the amount of beneficial bacteria present in the milk, but also doing so increases the food’s micronutrient profile – improving, in particular, the amount of B vitamins.  A 2008 study of over 82,000 Swedish men and women found that a high intake of cultured milk products seemed to lower the risk of developing bladder cancer2. Moreover, a high intake of cultured foods is linked to an increased barrier against microbial infection3.


Viili, though thought to originate in Sweden, is a Finnish cultured dairy food noted for its viscous, gelatinous and almost ropey consistency.  Indeed, the longer the strands produced, the more treasured the viili; indeed, some ropes of viili have been reported to reach upwards of one foot in length. Viili’s characteristic texture is the result of naturally present, beneficial yeasts and lactic-acid producing bacteria.  Its is mildly sour, and in many respects faintly sweet by comparison to other cultured dairy foods and yogurt, making it a good option for small children. Want to try it?  You can pick up viili starters online.


Where viili is eaten piimä is drunk.  A thin fermented beverage, piimä is less sweet than viili and faintly cheese-like in its flavor.  Due to its characteristically thin consistency and its sour almost cheese-like flavor it’s a good substitute for buttermilk.  When piimä starter is used to culture cream, it produces a slightly thicker version that makes for a beautiful sauce.  We serve it with pan-fried brussels sprouts. As with villi, if you want to try making piima, you can find starter cultures online.


Filmjölk is another treasured cultured dairy food.  Its bright and tangy flavor is quite versatile. Filmjölk is not as thin as piimä, and neither as thick as viili.  For this reason it’s well-suited to a variety of applications.  Filmjölk earns its tangy taste from lactococcus lactis and leuconostoc mesenteroides.   These bacteria, like others involved in fermentation, render the milk slightly acid and that its acidic environment coagulates the milk’s natural proteins turning the milk into sour, thick yogurt.  You can pick up filmjölk starters online.


Skyr is Icelandic in origin, and traditionally consumed at breakfast.  Though technically a soft cheese due to the inclusion of rennet, skyr is cultured with a starter that includes such beneficial bacterial strains as streptococcus thermophilus and lactobacillus bulgaricus. The whey of traditional skyr is quite sour and somewhat bitter and it is sometimes used as a substitute for vinegar.  Starters for skyr aren’t widely available, even online; however, if you’re lucky enough to find skyr at your health food store you can use the unflavored variety as a starter .  Mix it with warm milk, add a few drops rennet (which you can find online).  The skyr should coagulate or curdle within about five hours.  After which you cut the curds and strain them through a cheesecloth or butter muslin (you can find these in most health food stores or online) for twelve to twenty-four hours depending on your preferred thickness.

Tette Milk

Even more obscure is Norway’s tette milk, long heralded as a beauty treatment when drunk, which is produced by steeping the leaves of a blue-flowered Scandinavian meadow plant in freshly drawn milk.  The milk would then sit at room temperature until clabbered, and this herbaceous clabbered milk could then be used to culture more milk.  Milk drawn in the spring, and thus preserved, could be consumed well into winter provided it wasn’t disturbed by stirring which would break the curds and whey. Unless you live with access to the tette plant, you’ll be unable to make traditional tette milk; however, it’s lovely to consider, isn’t it?

Why Scandinavian-style Room Temperature Yogurts Are a Great Choice

Aside from the fact that cultured dairy products are simply wonderful for you (and taste wonderful, too).  I recommend room-temperature yogurts for people with limited time.  That is, if you’re one of the countless readers that emails me wondering how to fit traditional foods and from-scratch cooking into a life that also includes a 60+ hour work week, charitable commitments and raising kids, this is the kind of yogurt you want to make.  Most traditional yogurts (Bulgarian and Greek) are thermophilic.  That is, they culture best at temperatures between 108 and 110 degrees Fahrenheit.  That means, you’re usually using a yogurt maker or otherwise carefully monitoring temperature.  Viili, piimä and filmjölk culture best at room temperature.  To prepare them takes less than five minutes of your time and you don’t need any special equipment for temperature regulation.  Mix milk with starter, set it on your counter and in a day or two you will have a beautiful, traditional homemade yogurt.  Easy easy.

How to Culture Scandinavian-style Yogurts at Home

You’ll note that these Scandinavian cultured dairy foods are largely produced by adding a starter culture to fresh milk and then allowing the milk to naturally ferment – or clabber – at room temperature which is in slight contrast to the traditional yogurt to which many of us our better accustomed. Room temperature, or mesophilic, yogurts are easy to prepare at home.

  • Simply combine two tablespoons of starter culture (see sources) with up to one quart fresh milk and allow it to culture at room temperature for up to three days (depending on variety and preference), or until the yogurt solidifies and separates easily from the side of the glass jar when tilted to one side.
  • Reserve two tablespoons starter culture for a future batch and enjoy.
  • NOTE TO RAW MILK USERS: If you’re using raw milk to culture these yogurts, the naturally occurring beneficial bacteria in your raw milk will, over time, overtake the bacteria in your starter culture.  As a result, you’ll no longer be making viili or piima; rather, you’ll be making bonny clabber (which is also lovely).  To avoid this and maintain a pure culture, prepare a yogurt from milk that has been scalded and cooled (one tablespoon starter to one pint milk).  Then prepare a raw milk yogurt according to the directions above, reserving only the starter from your boiled milk to culture future batches.  This practice, maintaining a pure seed starter, ensures that the bacteria in your yogurt are not overtaken by wild bacteria in your milk.

Where to Find Starters

If I’ve got you all excited and you’re ready to start culturing your way through quarts of milk, you can find traditional mesophilic (that is: room-temperature) Scandinavian-style yogurt starters online (see sources).  I have not found them available any other place (aside from skyr).  With good care and regular culturing, your starter will last indefinitely.

This post was originally published in March of 2010 and revised on January 2, 2012.

1. Milk history, consumption, production and composition. University of Guelph. Accessed 11 March 2010. 2. Cultured milk, yogurt and dairy intake in relation to bladder cancer risk in a prospective study of Swedish men and women. Larsson et al. American Journal of Clinical Nutrition. October 2008. 3. Probiotics and their fermented food products are beneficial for health. Parvez et al. Journal of Applied Microbiology. 2006. June.

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What people are saying

  1. Che says

    So Beautiful! Covered all the bases~ Thank you for sharing and and inspiring while keeping this wisdom alive!~ Che

  2. says

    I have been making thermophilic yogurt at home for its bacterial properties, specifically acidophilus and bifidus. Are the bacteria in filmjolk and viili every bit as intestinal friendly as in, for example, Greek yogurt? I have been unable to find an answer to this question. Thanks for any reply.

    • Heidi says

      Sheryl: I’m a Norwegian living in Norway. When a recipe says sour milk, it usually means milk kefir. I know that several lefse-recipes call for milk kefir/sour milk (in Norwegian: surmelk).

  3. says

    Hi Jenny, I was wondering, are you sure piimä is different than buttermilk? I thought it was just the Finnish word for buttermilk, so I’ve always been confused as to why it is considered something different in Nourishing Traditions. Piimä is a byproduct of making butter, so wouldn’t that make it buttermilk?

    • Jenny says

      Everything I’ve read indicates it’s different … but if you say it’s the same, I wanna chat and get it straight!

    • Johanna says

      Sita: regular piimä is just fermented milk, not a byproduct of making butter. The byproduct of making butter is in Finnish called kirnupiimä.

  4. Missy says

    Jenny, you mention that if you use raw milk to make Viili that you will then eventually have bonny clabber. Do you know if one is more nutritious? Wouldn’t using the raw milk be more healthy than scalding it? Also, my doctor tells me to use goat’s milk. will that work the same?

    Thanks so much for all this great info!

  5. Patricia says

    I have been trying to find out if these mesophilic cultures are OK for GAPS. I make Fil Molk with raw milk and also with cream and it is devine! Contacted Cultures for Health but they could not tell me if the lactose is sufficiently reduced.

    I ferment the “mother culture” in store bought organic cream (non-homogenized but pasteurized) and freeze in tiny zip lock bags. When I am making my raw milk/cream batch I use a defrosted package of “mother culture”. Super quick and the mother culture seems to survive in the freezer for a few months.

  6. Aidan says

    Hey, this is great. Thanks for the tutorial. I want to try and make viili in my home soon.

    May I request a tutorial for cottage cheese made with raw milk? I love, love cottage cheese but have yet to come across a good tutorial online for making it at home with raw milk.

    I don’t want cream cheese or bonny clabber (super sour version of cottage cheese) or… Anything else… But a real cottage cheese tutorial! Now that would be super.


  7. Debra says

    What a wonderfully informative article. I’ve begun studying cultured milk, and made a couple of batches of SCD goats milk yogurt. I’m afraid I’m so dairy sensitive that even following the SCD 24 hours preparation wrecks havoc on my gut.
    I’ve got a file started that I’m saving recipes, instructions, etc. As I want to continue trying to find something my belly will tolerate. I’d like to include this information, too.

    Is there a printer friendly button that I’m missing?

  8. Wendy says

    I’m not completely understanding how to make it with raw milk. I scald my raw milk, let it cool, then I add my starter to that milk and let it sit on the counter 12-24 hours to make Viili yogurt and then I use this yogurt as my starter for future batches and save enough starter from this jar to make another scalded milk starter. Is this correct? How long will this starter be good for making future batches of yogurt? Thank you!

  9. Lisa says

    I’ve been making Piima cream because it is the best thing on earth! :-) I’ve made it by using a piima cream culture added to raw cream or pasteurized cream (mostly raw until my dairy had problems). I make it by leaving it out for 24 hours and then refrigerating. I’ve noticed that in the refrigerator, over time (more than a week), it forms a soft crust that is a light peach color, similar to the crust on young creamy cheese. It smells like that, tastes like it and is spongy like that as well (doesn’t dissolve in water the way the rest of the cream does). Is this normal? Is my Piima cream turning to cheese in the fridge? Should I scrape it off? Obviously, I haven’t died from eating it, but is eating it safe? It is more bitter than the cream itself. It does not have any white fuzzy mold on top of it, but clearly it is some kind of mold. (It actually happens more on the pasteurized cream then the raw, but it happens on both.)

  10. Gabe says

    Hei hei,
    Lovely post. I’ve been living in Finland for the last two years. Just wanted to say that Finland is technically not part of Scandinavia, but rather, part of the Nordic region (The Finns do not share the same Germanic background as the Scandinavians). However, their love of dairy is everywhere and any yogurt, viill, skyr with rhubarb and apple confit is ammmaaazzzinnggg.

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