
This is a simple tutorial how to make a sourdough from scratch. Sourdough is a important and great ‘ingredient’ when making chewy and dense bread with a crisp crust like the Danish and very popular rye bread. Making the first portion of sourdough is very easy and it only requires few and simple ingredients; all-purpose flour, rye flour and water. The only downside is that it takes about 5 days to ‘start’ the first portion of a sourdough. Once it is ‘up and running’ it is easily maintained by ‘feeding’ the dough once in a while.
As said, a sourdough is only made from flour and water – no yeast is added. Instead a sourdough is left in an uncovered bowl on the kitchen table and then it will slowly attract wild bacteria and yeast from the air. Over time microorganisms will start grow and fermented the dough. This process normally takes about 5 days. The dough is ready when it has small bobbles and when it smells nice and sour, like beer or a bit like vinegar. If you remember to use only the halve of the sourdough when baking, you can keep ‘feeding’ on the other halve and by that keeping it alive. If you use all of the dough you would have to start a new one from scratch.
When making the first portion of sourdough the process can be speed up by adding a little honey, buttermilk or some yeast. However, this can also cause the dough to over speed and eventually turn bad – the simple version is way easy to control.
Sourdough
1 portion
Preparation time: 30 minutes
Total time: 5 days
Ingredients:
All-purpose flour
Rye flour
Water
Instructions:
Day 1:
In a bowl; mix 1 dl (1/2 cup) all-purpose flour, 1 dl (1/2 cup) rye flour and 2 dl (1 cup) water. Leave the bowl on the kitchen table without a lid.
Day 2:
Add 1/2 dl (1/4 cup) all-purpose flour, 1/2 dl (1/4 cup) rye flour and 1 dl (1/2 cup) water. Stir in the mixture on a regular basis.
Day 3:
Add 1/2 dl (1/4 cup) all-purpose flour, 1/2 dl (1/4 cup) rye flour and 1 dl (1/2 cup) water. Stir regularly
Day 4:
Add 1/2 dl (1/4 cup) all-purpose flour, 1/2 dl (1/4 cup) rye flour and 1 dl (1/2 cup) water. Stir regularly
Day 5:
The sourdough should now start to ferments, where small bobbles appears and the dough gets a nice sour smell. Make sure that you stir in the mixture several times a day. Sometimes the dough separates but that is ok – you just mix it together again. The sourdough is now ready to be used. You can keep it in a glass jar which has been cleaned with boiling water.
Keep the Sourdough Alive:
If you are not going to use the sourdough for a while, leave it in the fridge and feed it every 14 days. Just remember to take it out 24 hours before you need it and feed it with 1/2 dl (1/4 cup) all-purpose flour, 1/2 dl (1/4 cup) rye flour and 1 dl (1/2 cup) water. Then the dough should be ready again.
If you use some of the dough on a regularly basis, just remember to leave some in the jar and then feed it from time to time. This will make sure that you always have some sourdough ready to be used. When you have some sourdough up and running it is not that vulnerable.

Do you ever cover the mixture with a cloth? We live in an area where small flying insects would love to land in this mixture, especially as it ferments.
Yeah some times I also have that problem. You can cover the mixture, no problem in that.
Hi Kim
We lived in Copenhagen Denmark for 3 years in association with the American Embassy. I LOVE the food – especially the bread. I love the excellent instructions you gave on how to make Rougbrod and am in the process of making the sourdough mix to try my first batch.
My question is: I don’t understand the “dl” measurement which I haven’t seen that often. The measurement I see more often in metric vs American/Imperial measurements is ml.
Can you clarify how a dl compares to ml. In some of the conversions I have found, some say 1 dl = 1- ml and some say 1 sl = 100 ml. Very confusing.
Thanks for clarifying.
Hi Anne. I hope that you are enjoying the time in Denmark. I’ll try to explain the ‘dl’ which means deciliter. A deciliter is a very typical way of measuring volume in recipes, at least in Europe. One deciliter is the same as 100 ml or 1/10 of a liter.
I always try to improve my recipes so that they are easily understood by people outside Denmark or Europe. So I am happy about you comment/question.
Thanks for posting this. Just got back from our first visit to Copenhagen and we loved the food there. Have never tried making a sourdough starter but will give it a go.
I hope you loved the city. Good luck with the baking :-)
My sour dough starter is not as bubbly as yours appears to be, what did I do wrong?I do have bubbles but it doesn’t seem as active as it should be.
Btw, thanks for the recipes!
Hi Luke
Hard to say, maybe just let it sit for an extra few days.
On day five of our sourdough “Yoda”. Feel like it has become one of the family, sitting on the kitchen table. We always say hello, good morning etc :-D Looking forward to getting started on the rye bread this evening.
Ha ha, I love that you called it Yoda :-) Hope the rye bread turned out great!
Hi Louise, thank you very much for these starter dough instructions. I live in Florida where it is super hot right now. My starter bubbled over on day five and smelled a bit like vinegar or like it got over sour. Can I still use it? It does not smell spoiled or rotten just that it seems to be super active and have a very strong sour smell. Not sure if I should throw it away and start over or if I can use it. I’d greatly appreciate your help. Thanks so much!
Hi Mima. The sourdough can sometimes be a little tricky. I know it can be super hot in Florida, I visit the state some years ago. I would recommend to try one more time and then keep the sour dough a cooler place and out of sun light. I can only think that the sour dough has been exposed to too much heat. Regards Kim
Hello and thank you for sharing this recipe! I have the same “problem” as Mima. I live in Italy and my sourdough is bubbly already on day 2. Is that OK? Should I keep going like this until day 5 or should I skip a couple of days? (I keep mine in the kitchen, but I could try to move it into the basement where it is cooler?)
I have looked more into this “problem” which I actually think is not a problem. When the sourdough bobbles and looks funny it’s ready, then you just skip some days and continues to keep it alive. The correct smell is a bit sour, beer taste or a little like vinegar. If it smells rotten then you should throw it out and start over from scratch.
I hope this helps. Regards Kim
Dear Kim,
Thank you so so much for your quick reply – I really appreciate it as I was desperately and hopelessly looking for an answer about what to do…I would hate it if the sourdough went bad! :( I guess the smell is as you are describing it right now, I will try to keep it cool and then use some of it to make your chocolate rye buns tomorrow. Can’t wait! I just hope that it will be OK until tomorrow morning.. By the way, if I don’t have any access to rye grains what could I use instead? I have some rye flakes, but not sure if I could use that instead?
Anyhow, I will let you know how it goes!
Ps. Even though I live in Italy we are actually neighbours – I come from Sweden! :)
Godnatt! :)
Hi Suzy
Thanks sounds great. I’m looking forward to hear how it went. I know it can be a little difficult to make these buns/bread. But when you get it right they are super. It’s difficult to say about the Rye Flakes if they will work. I think the rye grains are the best. However, you might also get a good result with the flakes. I’m also really interested in hearing if you get any good experience with rye flakes.
Sweden, yes then we were almost neighbors. I’m living in Copenhagen.
Regards Kim
Dear Kim,
I actually decided to await until day 5 anyway, which I’m glad for doing since the sourdough is getting stronger and stronger for each day – you should see it – it’s really bubbly and the smell is perfectly sour, but in a good way! :) I also placed some organic ripe fruit from our farm next to it which just seems to add to its fermentation process….It’s always hungry, and this morning I found some “hootch” on the top of it which I poured away (they say it’s a sign of starvation?) Anyway, tomorrow will be day 5 and I guess I will start with the buns tomorrow or the day after. I will let you know how it goes! :) If you want you can follow us on Instagram (terra terra.co) to see the result through images (We just started to follow you as well of course!)
Hello! I just wanted to thank you for the great recipe, pictures and tutorial. I am making your Rye Bread with grains and using your sourdough recipe. Looks very good and easy to follow, Nice video too. I will be reading your blog, Thanks! Lisa from Ventura, CA
Hi Lisa. Thanks for your nice comment – I am happy that you like the recipe :-)
Hello Kim,
I just came across your instructions on making sour dough. Most of the other recipes ask that half of the sourdough starter should be discarded daily and an equal amount of fresh flour and water be added.
Your instructions do not indicate this.
Your instructions seem to be easier to follow. My son’s girlfriend is Danish and i would love to surprise her with a decent Rye bread when she visits us in Vancouver. I do bake a lot for charity and friends..
I look forward to hearing from you. Thanks for the posting.
Thanks for the posting.
Hi Shahida. Yes I know that some recipes suggest this step. However, I have always just used this recipe I have here on my blog with success. I hope that it works out for you. Regards Kim
I’m making this sourdough for your danish rye bread but I’m not sure about something.
After I’ve taken out 1 3/5 cup of it for the bread, when feeding what’s left in the jar do I continue to use the same amounts of rye and AP flour and water for feeding every 14 days? It seems to me eventually there will either be too much or too little in the jar, depending on how often I make bread.
Hi Gina. Yes if you keep the sourdough in the fridge, just feed it with 1/2 dl (1/4 cup) all-purpose flour, 1/2 dl (1/4 cup) rye flour and 1 dl (1/2 cup) water every 14-days. You can also just keep it on the kitchen table and feed it everyday or every second day with the same ratio of AP flour, rye flour and water. Hope this helps. Regards Kim
I let my dark rye sour dough starter dye and am now starting over. I can’t find my original recipe source and came across yours which I want to try. However, I remember my first time doing this, it called for yeast. Is there a reason why yours doesn’t require yeast? Thank you
Hi Chelsea. The reason why my sour dough doesn’t require yeast is because it gets the ‘yeast’ from the air in your kitchen. Some recipes adds yeast which is a sort of a catalyst to speed up the process of making sour dough. I normally perfer sour dough made without yeast. I hope this answers your question.
Thank you Kim, I look forward to trying it without yeast in 3 more days!
Doesn’t the yeast come from the flour?
Yes, the yeast-effect is coming from the flour.
Great blog.
I am from Greece and love Nordic food. I believe that Mediterranean and Nordic food together is a great combination
Great recipe. i just made my first batch of sourdough and used it for bread. and it came out perfect.
i actually wanted to do the Rye Choc recipe as I am often travelling to Kastrup and just fell in love with this rye chocolate bread cookies.
Yesterday was the 6th day of the sourdough. I have some questions on the maintenance.
1) If i want to use it today do i need to feed it for one day?
2) When I use some is it better to replace it immediately?
3) Do i always need to feed it with the quantities mentioned or can i add more but keeping the ratios?
Thank you
Hi. Thanks for your comment. I’m happy that you like my blog and the recipes on it. Regarding your questions: normally you don’t need to feed it on the day 6th day when it is ready. However, if you uses some of the sour dough on the 6th day, you can just feed it after to continue keeping it alive. You can try raising the quantity of flour a little bit but I would normally use the quantities I have listed in the recipe.
Hi Kim: I have made this recipe consistently since my trip to Denmark last August= thank you for it! Couple of observations:
1) After I add the bulk of the flour and before putting it into bread pans, and then again after I add it to bread pans, the dough doesn’t rise. Can I skip this step and just put it in the oven? At least skipping one rising session?
2) It’s hard to get this bread fully baked. I only eat it toasted, because it’s so dense and then it “bakes” a little longer. I’ve experimented with the oven temperature and start out at 375 for 30 minutes to get a brown crust, then go down to 325 or 350 for an hour an a half. Ay thoughts on this?
Thank you so much,
Kimberly
I couldn’t believe it when I saw you had a recipe for the very same rye chocolate buns that I had sampled at that famous Copenhagen bakery you mentioned. I’d never had anything like them before, and I am so excited to make them! One question: when you store the rye sourdough starter in the refrigerator should it be covered? Thanks so much!
Hi Zelda. Yes I normally cover the sour dough when I store it in the fridge :-)
Thanks! I am not seeing as many bubbles as you have, so I am going to let it go a little longer.
Can you tell me if your recipe is different than those one would find on U.S. websites. I’m seeing pictures of stringy elastic looking starter, but yours looks more soupy than that. Danish rye bread is different than the sourdough they are making, so it would make sense that the starters would be different. Right?
Hi Zelda. I’m not quite sure how the ‘us Ryebread’ is compared to danish Ryebread. My sour dough is quite liquid and has a nice sour smell. I know other types of sour dough which are less liquid – those should also work.
Some sour dough recipies suggest that about day 22 or 3, you discard about a cup or so of the starter.
I was wondering why you would need to do that and if it would affect your final bread ?
I made your recipe. On the whole it was great ! The only think I noticed was that once I put it into the special Danish bread pans I bought in DK, it didn’t really rise any more. Therefore my final loaf was about half as “tall” as yours and other loves I have seen. I wonder why that would be ???
Thanks for getting back to me
Like so many others I visited Copenhagen recently and LOVE this bread and Smorgasbord. (Sp?) I will be trying your recipe this week. Wish me luck. :-)
Trying for the first time in the UK. I have managed to source all the ingredients but can’t find rye kernals locally. Guess I will have to try on line. Any idea of a substitute I could use?
Is there any way you would know that it is done? I saw another video where it said that when you put it in a jar it would double in size. I tried that with this dough and it didn’t do that so I got confused and started over. But the dough I’ve made this time doesn’t do it either so maybe this dough is not supposed to? Would love a tip on how to know that it is ready to use. Thank you