Anyone to share recipes and experience on brewing Boza beverage?
I come from Turkey; I live in Istanbul at the moment and I like boza very much. I have had some notes on brewing boza, but I've never tried it myself.
The reason I didn't try is mainly that the recipes for the general public calls for bulgur as the main ingredient. (Bulgur is traditionally a very popular food in Turkey and very abundant, so its easy to reach for the general public. Nowadays it has some popularity in Western world as well.) I'm sure that this is not the case for the boza made by special boza houses, i.e. relatively big industrial firms of the day or by the artisanal shops in the past.
As far as I know genuine product is made from proso millet as the main ingredient. (Here in Turkey, in metropolitan cities the only way to obtain it is to shop from a pet store. Its sold as a bird food. But even if you buy it there's a problem to mill it in order to get rid of its shell. Appearently it needs some sort of milling to use for boza and I don't know how to do it witout having special equipment. Because of this obstacle I believe, the recipes for the general public do not mention proso millet.
Some producers seem to add some amount of rice as well.
As those being said I am translating a recipe I found on the Web:
3 water glasses of bulgur 2 small cups (Turkish coffee cup or espresso cup, lets say) of rice 3 water glasses granulated sugar 1 water glass old (previously made) boza or a match box big of yeast (appeareantly it means bread yeast in paste form)
Bulgur is soaked in abundant amount of water previous night. (Means that it should be soaked for about 12 hours or so.)The day after, bulgur and rice is boiled to the degree that they are mashed throughly. Its treated with a mixer and mashed through a strainer.
That mixture is put on top of a stove with low heat. Sugar is added and stirred until it dissolves. Then taken away from the stove.
It is let to cool to a lukewarm degree. Stirreed from time to time. When its lukewarm, the old boza or the yeast which is dissolved in lukewarm water is added to the mixture. Its stirred throughly.
The mixture, closed with a lid, in a place around 20-25 °C, is left to ferment for 2-3 days. Its stirred from time to time. When you observe small bubbles in it, its done. Then, its transferred to a cool place.
Its served cold. Up to taste you may sprikle ground cinnamon on it.
For the yeast: As its the case in most of the world, here in Turkey general public has no refined knowledge of yeasts. The recipe calls for bread yeast which is very easy to obtain and it mentions a glass of old boza as an option which is obviously can serve as yeast to some degree. Most probably traditionally it was prepared with such a way from the point of the yeast. However, I'm not sure if the big producers of the day use some other yeast or not. You may do some experiments if you have some different types of yeast at hand.
For the bulgur-rice and water ratio: The recipe above is blurry for that. You should have tasted a genuine boza before to adjust it. A recipe calls for 2 cups of bulgur and 21 cups water. That may give an idea. I'll write my ratio in concrete terms when I try.
Under any condition, if you have never tasted boza before, its very hard -if not impossible- to tell that what you obtain resembles to genuine boza or not. I'll try the recipe above for myself -beginning tomorrow- and I hope I can say something in a week or so. Hopefully I may add some other recipe(s) as well. The one I already wrote is a very basic one.
The best boza in Turkey (Vefa, for example) is made from millet. Traditionally, the millet is boiled till it is very soft and mushy, then it's pressed through a sieve. This gets rid of the hulls. In the US you can buy hulled millet; I'm not sure what Vefa does but it's hard to imagine them sitting around rubbing millet mush through sieves by hand. :)
The other issue is "yeast." In Turkish, the word for yeast (maya) refers to anything that's used as a starter, whether it's for cheese, yogurt, boza, bread, etc. But they are all different things.
If you use store-bought bread yeast, your product will be heavily alcoholic, and that's not what you want. (The Greeks and Armenians of Istanbul did make a more alcoholic version but it wasn't considered halal by Muslims.) This may eventually go acidic because of secondary fermentation, like vinegar production, but I think the best way is to start your boza with already established boza. If you don't have that, you can make your own starter as follows:
Soak, then boil a small amount (say 2 tablespoons) of bulgur or millet till very soft, and blend or run through a fine sieve. Add equal parts sugar and water till you get something the consistency (or a little thicker, it doesn't matter) than boza. Cover with a cloth and let it sit out at room temperature for a couple days. In 2 or 3 days it will get sour and bubbly, but if you use this, your boza might not taste quite right. Repeat the process, but this time, after the mixture is cool, add some of your first starter batch. This time the fermentation will go a lot faster, and it should taste like boza - sweet and tart. Now you can make a large batch, and use your starter. Each time, save some of your boza to start the next batch. Once your starter is established, it should only take a day or so to make.
Scientific info for the biology geeks: :) What has happened is, the mixture was "colonized" by wild yeasts, some of which produce lactic acid, others of which do not. But lactic acid kills the other bacteria, and the bacteria that produce it "win" the battle. When you start your second batch, you then have a more active culture of lactic acid producing bacteria, and they ferment the batch before the "wrong" bacteria can take hold.
You could probably use a little bit of sourdough starter to start Boza. It has all the right microorganisms. I haven't tried it, but I would imagine that you could use vinegar "mother" as well.