Breaking Bread Interview #6: Hendrik Kleinwaechter, founder of The Bread Code

by Heather

Welcome to Breaking Bread, the interview series that highlights key people in the sourdough scene! In today’s post, I talk with Hendrik Kleinwaechter, founder of The Bread Code. Hendrik is a home sourdough baker in Germany who runs the popular YouTube channel The Bread Code, constantly testing recipes, techniques and ideas to make your sourdough experience easier.

Here, we discuss how The Bread Code was born, Hendrik’s early memories of bread, and his best advice for beginner bakers.

This post may contain affiliate links. For more information, see my disclosures here.


  1. Hendrik, you work as a software engineer in Germany. How did your sourdough journey begin, before The Bread Code was born?

Yes. I work as a software engineer, and I do a lot of web development. I’m a full-stack engineer, so that’s typically back-end and front-end. The back-end is the techie part, the database, the nerdy stuff, and the front-end is what you see in the browser.

My sourdough journey probably began when I was younger, at my mom’s place. She would always make this delicious bread, it was always warm, and the whole house just had this amazing scent of fresh made bread. We would have this nice garlic butter on top of it, and that’s the best food that I remember from my younger years. Also, in Germany, there are bakeries everywhere. I would say if there’s one food that we Germans can do, it’s probably bread. 

At some point when I was studying, I just didn’t have money to buy expensive food and things like that. So, I went to the supermarkets. I started buying my bread in the supermarket, and I no longer went to the bakery.

But I think everything started for me five years ago when I wanted to just buy honey in the supermarket. I was checking the labeling of the honey, and it said it wasn’t even from Germany. It said it was a honey mixture from Germany, the European Union and other European countries. And I thought, “Wait, I always thought I was buying German honey!” So then I started to check the packaging on the bread that I was buying, and I saw there was stuff inside that I had never even heard of, that I couldn’t even pronounce. That really got me thinking, “Why does it have to be so complicated? Why are there so many ingredients inside?” 

Hendrik from The Bread Code

I started with making a lot of pizza, because I really like eating pizza, and at some point the next logical consequence was to move on to bread baking. 

I think I first started to release my recipes about four or five years ago, and not on YouTube, but on GitHub. It’s a website for engineers, where they can just share some of their open source work. I shared them there because I could also keep track of what has changed in the recipes, and that’s important because a recipe is something that evolves over time. The bread recipes on GitHub directly started with sourdough because I was most intrigued by just having a bread that’s just made out of flour, water and salt. That’s what intrigued me the most. How can you make something so amazing out of just three ingredients?

Suddenly overnight, everybody in the engineering community was just talking about this one project of me releasing my recipes, and I didn’t expect that. So I just kept doing that for some time, and then I finally started to actively work on the YouTube channel just last year.

  1. Only a year, and you’re already over 86K subscribers! That’s amazing. So, where did the name “The Bread Code” come from?

Being an engineer and working daily with software, I thought, okay, what would be a good name? I think The Bread Code represents what I’m doing. I’m not so much about providing recipes; instead, I like to say that I’m providing some sort of a framework to bread bakers. I don’t give detailed instructions. I always give instructions in a way that is descriptive, like “this is how your dough should look at this stage”.

That’s also why my videos are sometimes so long, because there just are so many parameters, and I’m trying to help everybody navigate through the whole process. And so I’m providing a bread framework (or a bread SDK which is what engineers would call it) that you can use to bake amazing bread at home. So that’s why it’s called The Bread Code; it just matched with my background.  

Sourdough baked by Hendrik from The Bread Code
  1. That makes total sense. How has your sourdough journey changed since you started The Bread Code?

One thing that I didn’t expect about The Bread Code is that, as a content creator, you have to produce content that everybody likes. But we Germans really love our rye bread. For us, rye bread is amazing! My good friend Sune Foodgeek also loves rye bread. The one thing that we Germans are not able to do is convince the whole world that rye bread is amazing. I guess we need to upgrade the marketing of rye bread! 

On YouTube, everyone seems to like the white bread, with not too much whole wheat and not too much rye. So I’ve been baking a lot of bread in that style to be able to create content, although personally I like very, very, very sour rye bread! That’s my favorite bread, so if I could, I would make more rye bread.

  1. You’ve created so many resources for people, from flow charts and graphs, to YouTube tutorials and recipes. One thing I love about your YouTube channel The Bread Code is the sheer number of experiments you do. How is your experimental approach helping sourdough bakers? 

It’s probably not so much one single experiment that has helped sourdough bakers, but more the approach that I use. I show people that you need to experiment if you want to master sourdough baking at home. Of course the results are interesting, but it’s always sometimes very hard to say that this is just because of this one parameter change because let’s face it, it’s more complicated than that. 

Bread baked by Hendrik from The Bread Code

It could be just a slight change in temperature. It could be a different shaping technique that you have on your sourdough bread. There are just so many variables that could just cause a change. So, what you would need to do is just to have statistical relevance, probably bake a thousand breads just to confirm this experiment. I think the experimental approach is more reasonable; why not make two loaves at the same time and see if one small change has an impact on the final result of one bread?  

  1. As a follow up, what’s been your favorite experiment so far that you’ve done on The Bread Code?

My favorite experiment was baking with ice cubes to create steam inside of my Dutch oven. I was testing and I figured out that if you have too much steam, it might have a negative impact on your bread. Everybody says that you need to have steam, steam, steam, and more steam. But what I found is that if you have too much steam, you may get a gel-like consistency on your dough which prevents it from actually being able to rise fully inside the oven.

So, it’s about finding the sweet spot of little steam and a lot of steam. 

This also meshed with an experiment that I was doing before where I was testing baking in a Dutch oven at different temperatures. What I found was that going too hot definitely had negative impacts on the oven spring, which matches with the steam experiment because if you have more steam, you can transfer the heat faster to the dough, and that might not necessarily always be for the better.  

  1. You’ve interviewed a lot of big names in the sourdough space on The Bread Code. Who’s been your favorite interview to date, and why?

It’s really hard to say who has been my most favorite person that I’ve interviewed. I think all of them have been amazing in different aspects. For instance, when I interviewed Jim Challenger (@jimchall), I found it so interesting to see how much dedication Jim has put into making his business with the Challenger Bread Pan. I also chatted with Sune Trudslev (@foodgeek.dk) who has a very similar background to me, and it was just great to hear his thoughts on a couple of topics. Then I also chatted with Kristen Dennis (@fullproofbaking) and it was just amazing to see her dedication to making that lacy open crumb.

Hendrik from The Bread Code

I also chatted with Matthew James Duffy (@matthewjamesduffy) from Canada. He’s running a sourdough school these days and it was nice to see how he’s just trying to teach people from all around the world how to make amazing bread. But then also I was chatting with John from Proof Bread (@proofbread). He talked about the struggle he has when baking sourdough on a large scale. Baking one loaf of bread at home is so much simpler than having to make 300 or 400 at night. But on the other hand, just imagine that you are baking 500 loaves of bread in one night, and so you get to test shaping 500 times in a row. You would be on another level after just one evening in a bakery!

I also had the chance to chat with Mike from Rosehill Sourdough (@rosehillsourdough). He also works for Ooni and they make amazing pizza ovens. So, overall, it’s been amazing to be able to talk to experts from the different niches. I learned a lot from all of them.

  1. What’s your biggest piece of advice for a beginner sourdough baker?

I think the biggest game-changer for me was to use a small piece of the dough as an indicator during bulk fermentation, and monitor the volume increase on that small piece. So, just mix together your dough, give it a good bit of kneading, and then extract a tiny piece of that dough. Then put that into a small jar next to your main dough and check for the volume increase. To begin with, aim for a 25% size increase. That’s what Sune Foodgeek is suggesting. Then you can begin shaping your dough. This way, you won’t run into issues of over-fermentation, because I think the most common problems that people are having is that they either ferment for too little or for too long. This way, you will nail at least the first part of the fermentation – the bulk fermentation

Some people use a large clear container and they mark the outside to monitor their dough rise. This works too, but I don’t have such a container, and I can’t see the dough through my metal pot.

A word of caution: You have to be careful that your dough is at room temperature or else the small jar might heat up or cool down faster than your main dough, which would give you inaccurate results. There are some limitations to this technique, but try to use it and then experiment a little bit. You can go up to a 100% size increase! This depends on the flour that you’re using.

A few other tips: Use your finger to poke the dough to test that it is done proofing. If you have issues with scoring, just place your dough in the freezer for about 30 minutes, then go ahead and score and bake it.

I think that fermentation is the single most important parameter that you need to have a look at. The rate depends on where you live, on temperature, on altitude, on how active your starter is. So, it all boils down to mastering fermentation.  🍞


Follow Hendrik on Instagram @the_bread_code for all of the sourdough inspo! Also check out The Bread Code website and The Bread Code on YouTube.


Check out more interviews in the Breaking Bread Series:
#1: Kristen from Full Proof Baking
#2: David Kaminer from Raleigh Street Bakery
#3: Jim Challenger from Challenger Breadware
#4: Tyler Cartner from Wire Monkey Shop
#5: Kristian Tapaninaho, Founder & CEO of Ooni


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