Boza: Ancient Fermented Sourdough Drink

Boza is a fermented grain beverage widely popular in Turkey, from where it has spread to the Balkan States, the Levant, and even as far as Egypt. The history of boza, and its production from grains such as millet, barley, and wheat, and its fermentation with various sourdough starters, is fascinating.

Balkan style boza from millet

What is Boza?

Boza is made from extant local grains cooked to a porridge, inoculated with a yeast or sourdough starter, and allowed to ferment for a short time. The porridge can also be made with various botanicals as flavoring agents. 

After fermenting, the solids are strained out and a sweetener such as sugar or honey is added. It will contain about 1% or less alcohol by volume at this point, but also a rich strain of probiotics and vitamins. The consistency can vary from smooth like buttermilk, to a pudding that you eat with a spoon. The flavor is sweet/tart, and filled with umami. 

Boza History

Records of making and consuming grain beverages go back at least 9000 years, with mentions of millet boza specifically, traced as early as the 10th Century CE among the Turkic peoples. Its popularity then spread to the Caucasus and Balkan regions.  

The people of the Ottoman Empire notably became its very fervent fan base. From the 14th to the 16th Centuries boza making was a common trade. By the mid-1500s however, the custom of mixing boza with opium brought on the wrath of the Sultan, who banned its manufacture. With the rise of Islam, and prohibition of alcoholic drinks in the 17th century, boza was again prohibited and all boza shops were closed. This prohibition would be enforced, and then relaxed, several times in Ottoman Empire history. Still, travellers were able to find boza widely drunk, and at one time there were 300 boza shops employing over a thousand people in Constantinople alone.

Boza Ingredients

While boza from the the Balkans is usually made from millet, in modern Turkey bulgur (cracked parboiled wheat) is often used, and recipes can also contain rice. In Egypt, barley is commonly used. Some Balkan recipes call for baked wheat flour instead of bulgur, and sometimes maize (corn) is included.

Boza was traditionally a tart, and sometimes quite alcoholic beverage. After the prohibitive ruling by the Sultan, a sweet and non-alcoholic version was introduced in the 19th century and became much more popular than its sour and alcoholic predecessor. In 1876, brothers Hacı İbrahim and Hacı Sadık established a boza shop in Istanbul’s Vefa district that continues to serve sweet boza to this day. Modern Boza is allowed to ferment very briefly, perhaps 20 hours or so, and is sweetened with raw or turbinado sugar or honey before being refrigerated to inhibit further yeast activity.

Turkish style boza from bulgur with chickpeas

Botanicals

Historically boza was served with grape molasses (Greek: Petimezi) from Kuşadası, powdered cinnamon, cloves, ginger and grated coconut. Modern touches include garnishes such as mint, or pieces of fruit like pomegranate or persimmon. Some modern recipes may add a vanilla bean during the cooking process.

Fermentation Organisms

Traditionally, a sample saved from a previous batch was used to initiate the fermentation process, in a way similar to how sourdough bread is inoculated. Today the beginner can use a commercial sourdough starter, or create their own using a flour and water mixture exposed to the local ambient air.

Lacking these options it is possible to start a boza batch by adding yogurt and baker’s yeast. Alternately, mixtures of baker’s yeast and probiotic lacto/pedio bacteria blends can substitute.

Preparing Boza

Wash and cover the grains with fresh water

Soak the grains several hours or overnight

Drain the soak water from the grains and add more water to cover them

Cook the grains until they are soft adding water as needed

Liquefy the cooked grains in a blender with the some of the cooking water

Strain out the solids with a fine mesh strainer back into the cooking pot

Add the sugar, and more water to the desired finished quantity

Cool the liquid to lukewarm temperature and add the sourdough starter, (or yeast/yogurt) cover with a towel or cloth

Move the container to a warm place (such as an oven with the light on) at 21 – 27 ºC (70 – 80 ºF)

Ferment for 24 to 72 hours, stirring occasionally, and depending on how sour you wish to make it

Strain and transfer the liquid to a plastic jug, add finishing sugar, and refrigerate

Loosen the jug’s cap occasionally to release excess pressure

The boza will continue to ferment slowly and become carbonated and stronger in ABV

Serving Boza

In Turkey, boza is typically served cold in water glasses, perhaps ones with a handle like a mug. For additional flavor, it is often sweetened with sugar or grape molasses, topped with cinnamon and roasted chickpeas. A dessert spoon is sometimes supplied as well, as the boza can be as thick as a pudding, although it is usually about the consitency of milk kiefer.

Egyptian Boza with Date Sugar, Date Syrup and Ajwain Seed

Boza Health and Nutritional Benefits

Researchers that studied boza samples made from maize, wheat, and rice flours determined that on average they consisted of 12.3% total sugar, 1.06% protein, and 0.07% fat. Boza also contains vitamins A, B, and E, in a highly bioavailable form, and it provides the health benefits of a probiotic drink with its variety of lactic acid bacteria cultures.

A myth in the Balkan countries suggests that drinking boza regularly makes women grow bigger breasts! While there is no scientific support to this claim, some women are convinced that it works.

Balkan Boza Recipe 2 litres

250g Millet, 280g Turbinado sugar, 150ml Sourdough starter, 1.5 litres Water

Turkish Boza Recipe 2 litres

200g Bulgur, 55g Brown rice, 200g Raw sugar 150ml Sourdough starter 1.5 litres Water

Egyptian Recipe 2 litres

250g Pot Barley, 200g Date sugar, 150ml Sourdough starter, 1.5 litres Water, 100g Date syrup, Toasted Ajwain seed

Roasted Chickpea Recipe

1 can (398 ml) garbanzo (chickpea) beans, drained, skins removed, dried with paper towel. Coat with 1 Tbs cold-pressed grapeseed oil; roast 30 minutes at 190 ºC (375 ºF)) turning frequently. Toss with zest of 1 lime, 2 tsp white wine vinegar, sea salt to taste. Return to oven 3 minutes; cool. Store in airtight container.

Grape Molasses (Petimezi)

1.35 litres white grape juice reduced by boiling to 250 mililitres

5 comments on “Boza: Ancient Fermented Sourdough Drink

  1. Alison says:

    A great read! I did not know about the opium! Your formula is quite different to mine, as my starter is crafted with grain and sugar alone before adding to a batch and I notice I use less sugar to you. I’d love to hear how your taste-tests of this go.

    • Thanks for the feedback! People have liked it quite a bit. Some even like to “chew the bits” if I do only a coarse sieve treatment. The sugar I use almost totally ferments out so the recipes end up not very sweet and a little bit boozy. With the sourdough starter the fermentation takes off pretty quickly too! I think perhaps they were using poppy straw as a tea back in the day, though I’m pretty sure pure opium is water-soluble.

  2. Come visit us in British Columbia and you can! 🙂

  3. Alison Kay says:

    🙂

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