Zakwas Żytni: Sour Rye Flour Starter for Żurek (Polish Sour Rye Soup)

Step 1

At a later stage, you’ll need a cooled boiled water. I’m mentioning it now, so that the water has time to cool. If you have an activated carbon filter at home, you can use that filtered water instead.

Step 2

Prepare a 16 oz (500 ml) jar. We don’t want any bacteria in there, so it needs to get clean. There are two easy ways to sterilize a jar:In a microwave: pour some water into the jar, set it on the highest setting for 2 minutes. Normally, we would sterilize the lid in a pot of boiling water, but this time the lid won’t be necessary. Dry up the jar completely. On the stove: Using a detergent, wash the jar in the sink. Rinse thoroughly. Place the jar in a cooking pot, and pour boiling water over it. Wait a minute or two and remove carefully with a jar lifter. Alternatively, you can pour cold water over and around the jar and bring the water to a boil, cook for a few minutes. Then remove carefully from the pot.Check out a post on Wikihow for more tips on sterilizing jars.

Step 3

You don’t have to measure the amounts exactly. A general rule of thumb is: “one part of flour to three parts of water”. For the size of our jar, drop in ⅔ US cup (100 g) of rye flour.

Step 4

Pour a little bit (3-4 tablespoons) of boiling water in and mix well with a spoon. This will “wake up” the gluten present inside the flour.

Step 5

If you got some gooey mud at this stage - you’re in the right spot.

Step 6

Now, add the garlic. It’s also a good moment to add the spices in (all-spice berries, peppercorns, bay leaf, marjoram), but personally I skip this step - see my explanation under the “Notes” section.

Step 7

Fill the rest of the jar with cooled boiled water (or with water filtered using activated carbon filter). Mix everything together with a spoon.

Step 8

We don’t want any bugs in our 'Zakwas'.  Cover the jar with a piece of muslin, cheesecloth, or any other natural cloth and secure it with an elastic band or a piece of string. For that purpose, I use a muslin square that I chop into smaller pieces.

Step 9

The flour needs to ferment for 4-5 days, ideally in a shaded, but warm spot - 77°F/25°C would be ideal.

Step 10

Check on the jar every day. There is no need to open it and stir it - just let it be.

Step 11

In the first 3 days, you’ll notice tons of activity. If the garlic (or spices if you used any)  floats to the surface, I just rock the jar a little bit to submerge it.

Step 12

After 4-5 days at room temperature, 'Zakwas' is ready. The fragrance should be pleasant: distinctively sour, but not overbearing, not razor-sharp.

Step 13

Once it’s done fermenting, screw the lid on and keep 'Zakwas' in the fridge. It will be good for 2 weeks.

Step 14

Now you can use your Rye Starter to make Żurek Soup. If you skipped the spices in 'Zakwas' (as I usually do), remember to add them when brewing the soup.