Sour Rye Starter is the soul of Żurek, one of the most flavour-packed Polish soups. Even if you live thousands of miles away, it’s easy to recreate it at home.
All you need is good rye flour, water and…time. Just let the lacto-bacteria and wild yeast do their thing.
For the full list of ingredients & detailed instructions, please see the recipe card at the end of this post. But before you scroll, there’s important stuff to know below.
If you’re familiar with sourdough bread baking, this recipe will sound familiar. In essence, making Rye ‘Zakwas’ starter is a very similar process. The key differences lie in proportions and an addition of garlic, but the principles stay the same.
Once your Rye ‘Zakwas’ has fermented, try using it following these recipes:
- Classic Żurek Soup
- Żurek Wielkanocny (also known as ‘Polish Easter Soup’)
If you would like to learn more about flour ‘zakwas’ in Polish cuisine and what’s exactly going on inside the jar, here’s the full guide on Polish flour starters.
Do you need any special ingredients to make this Rye Starter?
There’s only one ingredient that might be trickier to source: wholemeal rye flour, ideally organic. This type of flour should be available in larger supermarkets and health stores.
It’s worth looking up your local flour miller online. They often offer their products directly – at competitive prices and much better quality.
🇺🇸 In the US: I’ve seen wholemeal rye flour available “in stock” on Walmart and Wholefoods websites. If you have trouble finding it in-store, you can get it off Amazon, for instance this Organic ‘Food to Live’ Rye Flour. (affiliate link)
This post contains affiliate links: Find out what that means.
🇬🇧 In the UK: Big supermarket chains (Tesco, Asda, Sainsbury’s etc.). Here’s a list of UK artisan millers, listed by region.
🇵🇱 In Poland, look out for ‘Mąka Żytnia Razowa 2000’. It’s available in larger supermarkets, health stores and online.
What dishes can you make with this Rye ‘Zakwas’?
Rye ‘Zakwas’ Starter is the magic ingredient behind an array of Polish soups, such as Żur, Żurek and Zalewajka. It’s also used to thicken the consistency of sauces and stews.
Can you make this Rye ‘Zakwas’ another way?
Yes, if you’re a home baker. If you keep a rye sourdough starter alive, you can use it to kick-start our Zakwas. Just add some of it to the recipe (at the bottom of the post), and Zakwas will be ready faster – even in just 2 days!
How do you know when this Rye Starter is ready?
Rye ‘Zakwas’ Starter needs 4-5 days to become ready. Properly fermented ‘Zakwas’ has a sharp, sour (yet pleasant) aroma. This smell reminds me of the leftover pickle juice (the fermented kind, not vinegary). If it turns bitter, that means something went wrong – check the FAQs below.
What diets is this Rye Starter suitable for?
Rye contains gluten, therefore the Rye ‘Zakwas’ is not suitable for gluten-free diets. I would recommend a Buckwheat-based Starter instead.
How long can you keep this Rye ‘Zakwas’ in the fridge?
Once Rye Starter has soured, it can be used straight away. Alternatively, pour it over into a jar, close the lid and store in the fridge for up to 2 weeks.
Can I freeze this Rye ‘Zakwas’?
I don’t think you can, at least not with satisfying results. I couldn’t find any information about it online or in literature. But it’s common to freeze the end product – the soup.
If you decide to freeze ‘Zakwas’ anyway, please let me know how it went. I’m curious what the result will be.
How do I reheat this Rye Starter?
There is no need to reheat it. Once added to the brewing soup, it will warm up naturally.
FAQ & Troubleshooting
Here you’ll find answers to the most common questions regarding Rye ‘Zakwas’ Starter. If you can’t find an answer to your question, please let me know.
🤔 Can you buy a ready-made Rye ‘Zakwas’ Starter?
In Poland ‘Zakwas’ for Żurek is sold in jars or bottles. It’s available in almost every store and in some bakeries. Make sure that the ingredients list is as short as possible: ideally just rye, water and garlic. If you have a Polish deli nearby, it’s worth asking if they have it in stock.
🤔 Flour sediment forms at the bottom of the jar. Should I discard it?
In short – no. To expand on that answer: it depends how thick you would like your soup to be.
The more of that floury ‘mud’ you add to the soup, the thicker it will be. If you’re unsure how to proceed, add the clear part first. Then slowly start adding the floury part, one tablespoon at the time. Taste as you go. Is the soup sour enough? Is it thick enough? If not, keep on tinkering with it.
🤔 How much Rye Starter do I need for a soup?
The more ‘zakwas’ you add, the sourer the soup will be. For 1 litre (approx. 1 lq quart) of a ready Żurek:
- You’ll need from 150 ml (10 tbsp) for a mildly sour flavour,
- up to 250 ml (1 cup) for a ‘properly’ sour soup. Or more, just taste and adjust.
🤔 It didn’t work! Zakwas is off / mouldy / bitter / smells funky…
Well, that happens sometimes. You have to remember that we’re letting the bacteria and yeast roam free, therefore the results aren’t 100% predictable. Here’s what you could try next time:
- Try with different flour. A different brand perhaps.
- Make sure that nothing floats above the water level.
- Limit the ingredients to a minimum – flour, water and garlic is enough. Some recipes mention adding a piece of rye bread into the jar, but every time I do so, my ‘zakwas’ goes mouldy.
- Make sure your jar is 100% clean.
- Is your room warm enough? Cold temperatures aren’t starter-friendly.
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