The Fresh Loaf

News & Information for Amateur Bakers and Artisan Bread Enthusiasts

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In order to learn how to write WebAssembly (wasm) code in the rust language (eyes glaze over... yeah, it wasn't an important detail) I've built a simple sourdough calculator:

There is plenty of scope for improvement.

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I tried Mike Giraudo's recipe, posted by dmsnyder.  It was as follows

  • 250g starter (60% hydration)
  • 600g water
  • 1000g flour
  • 20g salt

Makes two 875g loafs

 Mix all ingredients 2 minutes on low speed until mixed, then mix 9 more minutes on next level speed. Then a quick stretch and fold, rest dough 30 mins, then stretch and fold one more time. 

 Then cover and let dough rest for about 8 hours at room temp. 

 After 8 hours, divide and shape into loafs and then into bannetons or lightly oiled containers, cover- then into the refrigerator for at least 12 - 32 hours. (The longer the time, the more sour the bread)

 After refrigeration, place immediately into a pre-heated Dutch oven @475 for 20 mins and then uncover and cook for another 10 mins @450 (or until you like the color of your bread.) Feel free to use all purpose flour, makes for a great crumb.

I don't have a stand mixer, so I kneaded by hand, not quite to a window pane (knowing what was coming next).  Other than that, I followed this recipe to the letter.  Here are some of the details:

  • I forked a 60% hydration starter about 9 days ago, keep it at 10C, feed it nightly at 4:3:5 on white flour only (11.5% protein high grade).
  • Flour: mostly 11.5% protein high grade flour; some (about 30%) 10.5% AP mixed in due to running out of the former.
  • My "room temperature" for the bulk proof averaged to 19C.
  • My refrigerated proof time ended up being 25.5 hours.  I baked the loaves slightly longer because the color was too pale after only 30 minutes.

Here is the crumb:

 SF Sourdough Crumb

Nice crumb for 60% dough.

I've let it cool 8 hours, and just tried some.

The crust is chewy and very nice.

The bread has a mild sour tang.  Pleasant, and enough to make me go back for more.  Too mild presently, but I'm sure it will be more sour by tomorrow.

Unfortunately (and I'm being snobbish here), the sour tang isn't quite like San Francisco sourdough.  It's very close though.  A bit too much in the middle of the tongue and top of the mouth, rather than pulling at the back corners of my mouth.

But this is getting very close.

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It has just become clear to me that extraction rates of flour are not always comparable.

When someone says that straight flour (white flour, AP flour, whatever) is about 72% extraction, that means 72% of the whole grain was kept as flour.  28% was tossed out as animal feed, including the bran, germ, and some wasted endosperm.

On the other hand, when talking about patent flour and clear flour, the percentages are not of the whole grain, but of the straight flour.  So patent flour of 85% extraction is 85% of the straight flour (which was 72% of the grain).  So that's actually only 61% of the whole grain.

This link describes it in more detail:

Here is another page about it:

Here it is visually:

Milled Flours

Here are several links that use %-of-whole-grain when talking about extraction:

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I made this seeded multigrain a few days back.  I consider it a success but I would make changes next time.   It was light and soft (short from the oil) but not at all sour, and I'm not sure the tiny hard seeds are even digestible. Next time I might sprout and/or grind the seeds first, and use less oil (it was too shortened).


  • 30g 100% hydration starter
  • 520g water
  • 90g wheat flour (88% extraction)
  • 90g AP flour
  • 35g rye flour
  • 20g buckwheat flour

Let it ferment for 12 hours at room temp (averaged 19C).


  • 20g golden flax seeds
  • 20g chia seeds
  • 10g black sesame seeds
  • 15g pumpkin seeds
  • 15g sunflower seeds
  • 100g water

Soaked the seeds, let them absorb and "gel up".


  • All of the preferment
  • All of the seeds
  • 135g wheat flour (88% extraction)
  • 135g AP flour
  • 30g rye flour
  • 30g olive oil
  • 18g salt

I did several stretch and folds and bulk fermented at 8C for 8 hours, then divided and shaped and proofed at room temp for 2 hours.  It could have gone longer.


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Bread these days is much maligned.  The Paleo diet people think grains were a mistake.  The low-carb people think carbohydrates are the root of all evil.  And the gluten scare mongers imagine they all have celiac disease.  Even mainstream dietitians warn of the high glycemic index of bread.  What is a baker to do?

Many of these folks can't be convinced otherwise. They've accepted their beliefs about grains, carbs, or gluten in a kind of religious shared-delusional way that is impossible to argue against because it's not logical.

But for those reasonable people who do follow and understand argumentation I write this blog entry explaining each problem or supposed problem, and how it can be fixed.

The Paleo Complaint: Phytates and Lectins

Paleo people are quick to throw out words like "lectins" and "phytates" and they all seem to know that bran contains phytates and that phytates suck nutrients out of your intestinal tract and they get flushed down the toilet.  Fair point.

Well, white flour doesn't have any phytates because it doesn't have any bran.  Even most wheat flours have some of the bran sifted out.  Better yet, the sourdough process neutralizes almost all of the remaining phytates.  And even if you aren't doing sourdough, simply soaking your flour partly neutralizes the phytates by activating phytase, the enzyme that breaks down phytate.

As for lectins, they are ubiquitous in nature, practically everywhere.  But both cooking and fermentation break these down. In sourdough bread we do both.

Low Carb and Keto Diet People

I don't have much mitigating advice for these folks. Bread is not low carb or ketogenic.  They can still remain in ketosis with 50 grams of carbs per day, and that allows a small amount of bread. But it's probably best avoided in this case.


Let's face it.  Less than 1% of people have Celiac disease.  And most people who seem to be gluten intolerant haven't done rigorous studies to determine if the culprit is actually gluten.  The culprit might be (in my opinion) bran from unsoured bread.  After all, health people insist on eating whole wheat, but many don't realize that whole wheat is technically poisonous (depending on your definition of poison) if the phytates aren't dealt with.  So gluten is, in my humble opinion of course, probably not the problem.  Most of these people are experiencing the powerful force of what is known to researchers as the placebo effect.  Many gluten-sensitive people who try sourdough find that they don't have the same reaction.

Glycemic Index

So we come to the last complaint on the list. This is he most scientifically accepted complaint, and this is also the one I think we can do the most about.

[EDIT: and if you're not diabetic and you eat in moderation, don't worry too much about the glycemic index]

Regular white bread has a high glycemic index.  But that can come down in a number of ways.

  • Sourdough lowers the glycemic index
  • Whole grain lowers the glycemic index
  • Oil slows digestion and lowers the glycemic index [EDIT: spread it on your bread, don't add it to the recipe]
  • Seeds lower the glycemic index

While we are on the topic of seeds, many are saying they are a super food. What better way to get your seeds than in a loaf of bread?

In summary, for the health conscious, a sourdough bread with lots of seeds and with some butter or oil spread on it is probably the best prescription.

I'm currently bulk fermenting such a loaf.  I'll post pictures and the recipe if it turns out nice.


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The French typically use 10-17% rye flour and T80 flour for the rest.

Here in New Zealand I have limited choices.  But I have a flour mill.  So I've been making a flour close to T110 as follows:

  1. Hard White Spring wheat from the Canterbury region (organic, bio-gro, Demeter).  We don't grow much hard red winter wheat down here, AFAIK.
  2. Fine grind through my (somewhat annoying) hand cranked Country Living Mill.  Often I do a course grind, then a second pass find grind.
  3. Sift (bolt) through 18 hole-per-inch standard kitchen sieve.
  4. Sift (bolt) again through a finer (0.5mm?) honey strainer.

I calculated the extraction rate by weighing the final flour (734g) versus the original wheat (835g), giving 88% extraction rate.  This is in line with French T110 flour, so I will assume it has an ash content of around 1.1%.

On the market I can buy either High Grade flour (11.5% protein, similar to American All Purpose flour), or Plain Flour (10% protein).  I purchase the former from a reputable brand (Champion).  I presume it is akin to French T55 flour, which has an ash content around 0.56%.

Mixing these two flours in a ratio of 1:1, I get an ash content of 0.83%, which is smack dab in the middle of T80 flour's ash content.

I'm rather chuffed.

So my final mix is:

  • 450g Champion High Grade Flour
  • 450g Homemade bolted wheat flour
  • 100g Homemade coursely bolted rye flour (kitchen sieve only)

Since my breadmaking goal is to simply have one starter and one bread that I settle on, and then focus my efforts elsewhere, I'll be using this flour both to feed my starter and to make my bread.

Happy baking everyone!

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There is a graph going around which compares the growth of yeast to LAB across the temperature range.  The yeast being compared is C. milleri.  What disturbs me about this graph is that people interpret it as being the only yeast relevant to their sourdough.  It's not.

The Graph

C. milleri is not the dominant yeast species in ANY of the 567 sourdough samples genetically analysed by the .  However, a lot of research has found C. Milleri to be present in the most powerful starters. Most of the older sourdough samples (the best and most well known) are dominated by the famous and well known Saccharomyces cerevisiae.

S. cerevisiae has been studied quite a lot, and its temperature dependent growth is fairly well studied and modelled [1][2][3][4].

I include a much better graph for this yeast (the upper solid line marked "Sc" is Saccharomyces cerevisiae.  The lower dotted line is irrelevant).

I think both yeasts are relevant.  The optimal temperature for maximizing your starter's leavening capacity [Edit: probably not, too many complicating factors, especially LAB competition] probably depends on what temperature you've been keeping it at (and thus the balance of yeasts), but I would expect it to be around 29-30C, which is damn good for both of these yeast varieties.



[1] Cheung et al., 2015, The Effect of Temperature on the Growth Rate of Saccharomyces cerevisiae.

[2] Mensonides, F.I.C., Schuurmans, J.M., de Mattos, M.J.T, Hellingwerf, K.J. and Brul, S. 2002. The metabolic response of Saccharoymces cerevisiae to continous heat stress. Molecular Biology Reports, 29: 103-106.

[3] Authur, H., and Watson, K. 1976. Thermal adaptation in yeast: Growth temperatures, membrane lipid, and cytochrome composition of psychrophilic, mesophilic, and thermophilic yeast. Journal of Bacteriology, 128 (1): 56-68.

[4] Salvado, Z., Arroyo-Lopez, F.N., Guillamon, J.M., Salazasr, G., Querol, A., and Berrio, E. 2011. Temperature adaptation markedly determines evolution within the Genus Saccharomyces. Applied and Environmental Microbiology, 77 (7); 2292-2302.

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I was six when the Larraburu Brothers Bakery shut down. I don't recall what the bread tasted like, and I'm not even sure I ever had any. But I'm fascinated by the history and how widespread and adored this bread was. The number of loaves, the loaves shipping around the world, even to France, indicates that it wasn't just a small group of aficionados that were keen on this bread.

I grew up on Colombo rolls and sliced bread, Oroweat rye, and 'artificial' sourdough baguettes from Safeway.  And I always had a Boudin bread bowl with clam chowder whenever I visited San Francisco.

Living in rural New Zealand, it's very hard to find San Francisco style sourdough bread. A local baker looks at me quizzically when I ask for sourdough bread that is intentionally sour. He tries to explain how people misunderstand, and that sourdough doesn't mean the bread tastes sour. I then have to counter-explain that I know this, and that bakeries in San Francisco did intentionally ramp up the sour because some people like that taste.

Like many on this board I'm still searching for my perfect bread to make every weekend. I'm pretty sure it won't be a Larraburu clone, but I think I will borrow some aspects of that bread. Understanding it is still a worthwhile endeavour.

Anyhow, this post is about my research into Larraburu Brothers bread, and my attempts at making it.

In comparing the NYT article ['NYT'] to the Galal et all paper ['Galal'], I notice some differences, but also a lot of confirmation.  Here is the superset of data from those two sources, including my take on why they conflict and how to resolve the conflicts.

GALAL: Each day a piece of straight dough or starter sponge known as the "Mother" is saved and refrigerated to be used as a starter sponge the following day.

NOTE: we don't know the refrigeration temperature, but we know that regular refrigeration is part of this starter's life.

NYT: A baker will take about two pounds of dough for a previous day's batch, and this is the starter for the next day's run.  The starter is left to rest for a few hours and is then placed in a dough mixer with salt, flour, and water. When this is blended, a sponge, as it is called in breadmaking circles, is produced. The sponge in this case weighs about 600 pounds. It is then divided into a dozen 50-pound pieces.

NOTE: At 50% hydration (from Galal) this is a 1/100/200 feeding, which is quite substantial.

GALAL: The starter sponge consists of 100 parts of clear flour (14% protein), approximately 50 parts of water, and 50 parts of the starter sponge

NOTE: This is a 1/1/2 feeding, 100-fold different from the NYT article. Personally I trust researchers to get facts more correct than I do newspaper reporters who are notoriously error prone. However, the bakery did have to make a hell of a lot of bread, and the reporter specified "two pounds", "600 pounds" divided into a "dozen" "50-pound" pieces, which is all self-consistent.  One way to resolve this difference is if the Galal paper had a single misprint. If it instead read "and 0.50 parts of the starter sponge" it would be exactly in line with the NYT article. Nonetheless, that is a very heavy dilution of starter material, and so I am still somewhat skeptical.

NOTE: The other inconsistency is that the NYT article suggests that the sponge contains salt. The Galal paper doesn't include salt in the sponge.

GALAL: The ingredients are mixed and fermented for 9-10 hr at 80F

NYT: Each of these pieces is put back into the mixer and more flour, salt and water is added. Each of these produces about 800 pounds of dough.

GALAL: The bread dough is made by mixing 100 parts of flour (12% protein), 60 parts of water, 15 parts of sponge, and 1.5-2% salt.

NOTE: Based on NYT, the sponge is 0.0625% of the final dough weight. Based on Galal, the sponge is 0.0849% of the final dough weight. These values aren't too far off each other. My best guess is that the bakery in 1976 was operating on a slightly different recipe than back in 1964.  And I suppose the value from 1976 by Galal is probably more reliable and/or represents improvements that the bakery made over those 12 years.

GALAL: The dough rests 1 hour, and then is divided, molded, and deposited on canvas dusted with corn meal or rice flour.

NYT: This dough is allowed to rest for an hour and is then molded, weighted and shaped.

NOTE: nice to see some consistency here between the two accounts.

GALAL: The dough is proofed for 4 hr at 105 F (41 C) and 96% relative humidity...

NYT: The resulting loaves are "proofed" in a dry steam box for four hours

NOTE: Again, nice to see some consistency here between the two accounts.

NYT: When they are removed, they are left to stand for another two to three hours.

GALAL: ...and baked at 420F (216 C) for 40-50 minutes in a Perkins oven with direct injection of low pressure steam (5 psi).

NYT: Finally they are baked 40 minutes.

NOTE: Again, complete consistency


So these accounts are rather consistent, and they fill in the gaps in the other's story. The biggest inconsistency is the amount of mother added to the sponge. Is it 1/1/2 or 1/100/200? I should think if it was 1/100/200, 9-10 hours at 80F would not be long enough to visually activate the sponge. So the bakers must have been working blind.  It does, however, allow for a long (4 hour) hot (41C) bulk ferment.

This weekend made a bread with mostly white flour, a smallish 10% sponge, and 5 hours fermenting at 39C (the hottest my incubator runs at). It worked out just fine - it may have overproofed slightly, but it still had some air and oven spring and a nice enough crumb for my tastes.

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