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The Basic Sourdough (github.com)
69 points by hendricius on May 6, 2018 | hide | past | web | favorite | 19 comments

I wouldn't call this "An engineer's guide". It's a lay guide written by a German using metric. If one wants an engineering level of scientific expertise, look at "Advanced Bread and Pastry" by Michel Suas.

For example, we grind our own flour, sieving out the bran but including fresh germ, for a spectacular difference in flavor. However, bread flour needs to be aged, or else the loaves will fail to rise properly. However, aging home-ground flour will turn it rancid and grey. The search keyword for this issue is "green flour". Suas has a solution: Add 30 parts per million of ascorbic acid, as a dough conditioner.

How does one reliably add such a small quantity of ascorbic acid, in a commercial bakery or at home? A true engineering problem. Thoroughly mix ascorbic acid 1:20 with white flour. Now take some of that mixture, and thoroughly mix it 1:20 with white flour. One now has a 1:440 mixture one can actually weigh.

This made all the difference in the world in my sourdough bread baking.

We grind using a Wolfgang Mock KoMo Classic Grain Mill, and sieve using a #25 Gilson 12in Round Test Sieve in an 8 quart Vollrath steel bowl. We hydrolyse overnight; an hour is just genuflecting. We add 350g of water for steam, as popularized by Thomas Keller; a few spritzes of a spray bottle is an ineffective 10g of water.

To convert that much water to steam takes a lot of mass. Indoors, we use a Vollrath Company 68369 Bake/Roast Pan filled with several spools of stainless steel chain. I plan to add pieces of aluminum plate to increase the mass further. Outdoors, in a Komodo Kamado ceramic charcoal cooker, we use a giant cast iron skillet with the handle sawed off, also filled with chain. I use a slab of ice outdoors, to buy time.

It takes 80 calories to thaw a gram of ice, 100 calories to bring that gram to the boiling point, and a whopping 540 calories to then turn that gram of water to steam. By weight, steel holds about 13% as much heat energy as water. These numbers explain why one needs so much metal to boil the water, and why it hardly matters whether the water starts out as ice or hot water.

For example, to turn 350g of cold water into steam, using metal heated to 450 F (132 C above boiling) takes about 28 pounds of metal. To turn ice into steam (giving one a slower fuse) takes about 32 pounds of metal.

What does the steam do? It isn't simply keeping the crust damp, or one would far more easily spritz the dough. (In grade school a teacher tried to tell us that candle wax slowed down the burning wick; similar skepticism is called for here.) The dough is the only thing in the oven cold enough to condense steam back to water. The energy used to turn water to steam is delivered to the bread as the steam turns back to water. Physics abounds in conservation principles, and this is one: The energy has to go somewhere. As a thought experiment, imagine bashing the bread with a baseball bat, with all your force. Then imagine spritzing with a plant mister. Trust your intuition; which is more force? As a second thought experiment, imagine spritzing your bare hand and sticking it into the hot oven for a few seconds. Now imagine sticking in your bare hand as you turn 350g of water into steam. In which scenario do you then imagine a visit to the emergency room?

Scale matters.

Great feedback. Why not open up a pull request and add some of your findings? That would be great additions.

I wonder if it might be easier to do the serial dilution of the ascorbic acid in water. It should be much easier to thoroughly mix than flour. If you're adding water to the mixture anyway, you can replace some or all of it with the diluted ascorbic acid.

My bread-making is much more primitive, but if i add salt and sugar, i do it by dissolving them in the water, to make sure they're evenly spread throughout the dough.

Scale indeed matters but you can use this to your advantage another way. I use the Lodge Cast Iron Combo Cooker that Robertson recommended in Tartine. The confined space means you need very water to create an appropriate amount of steam. I have found the water coming off the dough as it bakes to be sufficient, but a very small amount of ice can always be tossed in just before covering. The cooker is enclosed so you don't loose steam if you have a gas oven like mine that vents and makes conventional steaming more or less futile. And of course, that mass of cast iron all around the dough pounds radiant heat into the dough like a boss.

I ordered the combo cooker and a cast iron pizza pan from Amazon. This ridiculously heavy parcel shipped free. Life is grand.

Suas' book looks very interesting. Do you know how Modernist Bread compares?

All of this information (including part #1) is missing a key element: temperature. Temperature should be considered to be an "ingredient" when making sourdough bread. It's not as simple as "do X on day Y, and you'll have sourdough". You may end up with tart/acidic dough...but not proper sourdough.

For a great introduction to making sourdough, I recommend reading the book, Tartine, by Chad Robertson, and browsing Maurizio Leo's amazing sourdough blog: https://www.theperfectloaf.com/

I found Tartine to be frustratingly vague at times, but Maurizio's blog is phenomenal.

It would be really great if you can share your information on temperature.

I've been baking my own dark rye sourdough bread for several years now and I think this guide really overcomplicates things.

You can get very good results with minimal effort: I spend about 15 minutes on my bread, and I bake it every 3-4 days. 10 minutes to mix the dough in the morning, and then another 5 minutes to put it in the oven in the evening, for an hour. Put aside some dough before baking, feed it with some flour, and you're done.

350g type-2000 rye flour (full grain)

~170g any other flour (I use a mixture of bread-baking flours and some white flour)

1/2 spoon salt

starter (I use about 150ml to 250ml, but it doesn't matter that much)

Water: about 300ml, but this depends: experiment.

6-8h to ferment and grow.

This dough flows, so you need to bake it in a form.

This simple procedure reliably produces great tasting dark rye bread (darker than the one shown in the pictures). If you have lots of time, by all means, experiment and go wild, but if like me you deal with negative time, don't overcomplicate things.

Rye starter or white flour starter?

My favorite rye sourdough is this one from Breadtopia: it goes kind of crazy on flavorings (caraway, anise, fennel, molasses, orange zest) but the results are spectacular. Plus there is a video to take you through it step by step - great for people new to sourdoughs or ryes. Plus plus there is an instant yeast version if you don't have a starter.


Rye starter, but after the first bread the starter is whatever you mixed for the bread, plus feeding every 2-3 days with rye flour.

Here again, keep things simple: don't worry about salt in your starter, as long as you feed it every 2-3 days, the effective salt content will go down and things will be fine.

The current starter I have in my fridge also has sunflower seeds, because that's what I mix into my bread. Who cares?

Again: you can go as complex as you wish with your bread, but the advantage of rye sourdough is that it can be dead simple to make and take very little time, with excellent results. This is what makes it great in my book!

This post is a followup to this one: https://news.ycombinator.com/item?id=16946178. The other post is part 1. The post is about making your sour dough.

This post however is about how to use the made sourdough to actually bake a sourdough bread. I hope it's not too confusing.

The title of this caught my eye - I feel like more and more engineers are baking bread as a hobby (the way photography used to be). So much so that there's a fiction novel about an engineer who gets started in sourdough: https://www.amazon.com/dp/B06XC41K6G/ref=dp-kindle-redirect?...

I love the format of breaking apart the starter recipe and then the baking steps. Thanks for sharing!

Anyone looking to make good sourdough (or any other kind of) bread should read Ken Forkish's "Flour. Water. Salt. Yeast." Including the OP - there a few things that could use improvement in both their method and recipe:

1. Ideally, for home baked bread, you always want to use a heavy dutch oven. A heavy dutch oven retains a lot of energy, which provides a consistent environment for the bread to bake in (opening an oven door, no matter how hot, rapidly lowers the temperature), but more importantly retains the steam that the bread emits. This both causes proper crust to form (look for the micro bubbles on the skin of the bread) and makes the entire loaf rise significantly more.

2. The hydration at 70% seems low. While low hydration makes handling dough easier, it also changes the taste - in my opinion, for the worse when it comes to bread. With a bit of practice, proper fermentation, shaping, proofing, and enough gluten formation, even a 78% hydration dough is not that hard to handle. I've baked a 1.8 kilo boulé without any shaping support on a simple pizza stone without having the dough "leak" (in general, if it is "leaking" post proofing, the dough has probably been overproofed and the gluten has weakened).

3. Fermentation time seems really low. Most sourdough types I am familiar with take overnight to ferment, and then 4 or so hours in the proofing basket to be fully ready. I've never baked after such a short fermentation period as described in the article, but I would imagine the resulting bread does not have the full airation, flavor, and texture that it otherwise would.

4. Technique - in my experience and as far as I have read, you do not have to knead at all. Most dough need only 3-4 rounds of "folding" during fermentation, where each edge of the dough is stretched and pulled over itself. That forms plenty of gluten. Shaping post-fermentation is similar, where after the edges are pulled over, the loaf is inverted on the seam and gently dragged around to create surface tension. _Definitely do not knead during shaping_.

For what it's worth, making your own bread is great. My first results were barely edible shame-disks with the texture of hardened gypsum, but after I got a handle on the correct techniques (and more importantly - patience) I have not purchased bread in a store for the better part of a year.

Great feedback. I agree 70% hydration might be low. But it is a good way to start baking. I highly suggest that everyone should A/B test this variable and see which loafs he likes more.

One of the better techniques I’ve picked up (pretty sure I got it from https://www.amazon.com/Flour-Water-Salt-Yeast-Fundamentals/d...) replaces the kneeding steps with folds during the first 2-3 hours of bulk fermentation. Basically after mixing in starter transfer to large fermentation vessel, reach under the dough from 4 corners one at a time, grab and pull over the top of the dough to opposite corner. Wait an hour and repeat, wait 2 hours and repeat, then let fermentation do it’s thing.

This saves a lot of effort, mess, and prevents dough from becoming overworked. Effort that can later be expended in dough shaping steps ;-).

Yes this works with strong all purpose flour. What happens if you use rye dough? You can't stretch and fold it. The rye has too weak gluten structure. It will mostly fall a part.

If you like this kind of stuff, you'd enjoy this: http://girlmeetsrye.blogspot.com/

For those interesting in fermentation in general, I can recommend the book "Wild Fermentation" by Sandor Katz.

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