Sourdough Hands: How Bakers and Bread Are a Microbial Match | Hacker News Reader

Sourdough Hands: How Bakers and Bread Are a Microbial Match

npr.org

149 pointslnguyen49 comments

In the southern part of India, it is common to have Idlis (fermented rice steamed dumplings) for breakfast and most households make Idli batter the previous night, and let it ferment and raise. The more the batter raises, the softer the Idlis are (and sour), and the mother often summons the kid to stir it with their bare hands. It is always the kid whose microbes help the batter ferment the most. This dubious honor fell on my hands, no pun intended. Most nights, before we slept, my mother used to shout out to come and stir the batter.

This is a charming, wholesome, and interesting anecdote. Thank-you for sharing.

Those sound interesting. Got any recipes?

This is a pretty good one - https://www.youtube.com/watch?v=UGnYu88A2Ws

20+ years ago I tried to bake bread a time or two, and it failed. I "recently" tried again, whilst taking care of a small child - on the basis that even if it went horribly wrong he could sit in his chair and play with dough for a while.

This time around almost all my breads have risen, and turned out to be wonderfully edible. My preferred recipe is cobbled together based upon numerous other ones I've seen, and uses yeast, flour, salt and water:

https://blog.steve.fi/this_is_mostly_how_i_make_bread.html

But I've also had a lot of fun with sourdough, the flavours are much better and despite the longer time involved I think it is definitely worthwhile.

I've baked a loaf of bread each evening this week, and tonight I'm taking the night off. But no doubt I'll be baking again on Saturday & Sunday - as I've just found another interesting variety of (Finnish) flour to try using!

This is kind of interesting because your recipe is 95% hydration (water / flour - this is how bakers do ratios), which is crazy high! I've never heard of this before, but I see you don't really shape it so much as scoop it into the dutch oven, which makes sense. Something like 55% is normal for commercial bread, 70% hydration would be much closer to a nice sourdough from the bakery, 75-80%ish for something like ciabatta (using bread flour w/ approx 11% protein) or when you are using whole flour.

Yup I didn't want to complicate that post by talking about bakers-percentages, but you're right it is higher than average. I've juggled different amounts in this recipe before finding the sweet-spot I prefer, but anywhere from 80% to 95% seems to work.

100% is a bit mixed, which is a little disappointing because it makes weighing a lot easier if you're using a balance-scale as I do most of the time.

I was amazed by how long he bakes it and now that you pointed that out, I think that's why. If I baked my usual bread recipe at 475F+ for an hour, it would be a rock!

This is very close to my recipe too! I keep a ~8 litre container in the fridge with dough always ready to go (pizza or bread). Whenever it runs low 2 lb flour, 1.5 Tbsp salt, 4-3/4 cup warm-ish water. You can add yeast or not. If it's still new 1.5 Tbsp yeast though I've had great results with far less or none if the container still has old dough in it.

I love that the dough is always there ready to bake something yummy whenever I want.

The cover of the new "Noma Guide to Fermentation" is an illustration of this phenomenon. https://www.workman.com/products/the-noma-guide-to-fermentat...

P.S. It's an awesome cookbook; highly recommended.

It's the craziest cookbook I've ever seen! There's a recipe for fermented (for 75 days) grasshoppers. As a serving suggestion it suggests mixing it with butter, cooking pancakes in the butter, and serving with 'a good caviar'.

We already brew cider and make kefir and various lacto-ferments in our house, but building a fermentation chamber and fermenting proteins for months in order to make something that keeps in the fridge for a week? I love the idea, but the reward/effort ratio is rather poor

I’m reminded of Rogue’s Beard Beer[0], which was made with yeast cultured from a brewer’s beard.

0: https://en.wikipedia.org/wiki/Rogue_Beard_Beer

Oh but it gets worse (well, depends on how you look at it) - https://pulptastic.com/craft-beers-are-so-2015/ .

Some people on the Milk the Funk community harvest yeast of basically anything someone sourced it from sheeps wool to call it Lamb-eek.

Gastropod has a great episode on Sourdough that's worth a listen if you like this article:

https://gastropod.com/secrets-of-sourdough/

I started baking sourdough bread lately, it takes about 15-20 minutes of work over 3 days to produce a loaf, from my starter, flour, water and salt.

It’s really rewarding to create something from scratch with simple ingredients.

Back in 2001, during the dotcom crash, I was unemployed a few months, and really got into sourdough at that time. It was pretty awesome. But loaves keep their own time, so I couldn't maintain it when I had a job again.

fwiw, I got my culture from grapes mashed in flour, per Nancy Silverton's Breads from the La Brea Bakery recommendations.

There's a name I only just discovered!

A friend had a Nancy Silverton pizza while in LA a couple of months ago and raved about it (she usually doesn't rate pizza highly for some strange reason), so we followed her recipe for pizza dough: https://www.seriouseats.com/recipes/2011/10/nancy-silvertons...

It was the first time I've ever made 'bread' and been happy with the result - it was some of the best pizza I've ever had. I almost makes me want to try making a sourdough again but I don't eat a lot of bread these days.

Myhrvold & Company poured cold water on the idea that grapes and raisins help a starter get going in Modernist Bread. I believe they went into detail on a "Bread Crumbs" podcast you can find on Heritage Radio. Probably this episode:

http://heritageradionetwork.org/podcast/mother-may-i/

These days, I'd buy a starter online. There's a market for them now, that wasn't really there when I got into it.

Why?

Mix flour and water, let it sit for 5 days, adding a little bit of flour and water daily to feed it.

You don't need to purchase a starter.

Mostly to see what it's like. The businesses selling starters focus on historically interesting, important, or notoriously good starters (like the "San Francisco sourdough", or the oldest known starter in the world, salvaged from an Egyptian tomb). I've done my own wild starter, and my daughter has also done wild starters (in her case, she made a rice bran starter for making Japanese nukazuke pickles).

So mostly, it's the academic interest.

I like the idea of incorporating locally available microbes but forgive my ignorance: is it safe?

Oh, it's perfectly safe. You can tell by the smell... a healthy sourdough culture smells healthy, a rotten culture smells rotten. The yeast/bacteria system is extremely tough and resistant to other microbes and molds.

Whenever you feed your sourdough starter, or add locally bought flour, or anything along those lines you are introducing locally available microbes.

A sourdough starter from SF won't be a SF sourdough for long just because of the microbes in the air/flour as you continue to feed it.

It becomes it's own living and breathing organism that you have to take care of or it dies.

I did it for years and my family's still here :-)

Survivor bias!

I bake all our bread, and it's sourdough, every two or three days. I wonder what effect this has on my overall health in a positive or negative way.

EDIT: To be clear, this article is about microbes on the hands of sourdough bread bakers. I'm curious about what effect these microbes on my hands have on my body, if anything. Not the ingestion of my bread.

I also keep a starter and bake sourdough regularly.

The only thing IMHO that can be an issue is just eating too much carbs (because it's so damn good) or sensitivity to gluten. However, it is known that sourdough/pain-au-levain is more digestible than regular bread for folks with gluten intolerance. Sourdough is decidedly more acidic (that's why it's called "sour") than dough which has been risen with commercial yeast. This acid partially breaks down the gluten in the dough during fermentation.

People have been eating naturally fermented bread since the dawn of civilization. The bacteria and yeast in properly fermenting dough do an excellent job of keeping any nasty stuff out.

> However, it is known that sourdough/pain-au-levain is more digestible than regular bread for folks with gluten intolerance.

I’ve heard this many times, but I don’t know if it rises to the level of “it’s known”. It’s not even clearly known that “gluten intolerance” exists outside the context of celiac disease, and sourdough definitely does not help with celiac.

There is a theory that “gluten intolerance” is actually intolerance of certain sugars, sometimes called FODMAPs, that are found in wheat, rye, barley, and quite a few non-cereal foods. I’ve never seen a paper about this, but I could easily believe that many sourdoughs ferment those sugars, making the bread more tolerable.

Finally, a little anecdote about gluten intolerance. I know someone who claimed to be gluten intolerant. She felt much better when she avoided gluten. At one point, I baked a fresh challah, and she decided to make an exception and try the challah. After eating maybe a pound of challah all by itself, she felt terrible. And lo and behold, we had a diagnosis! Eating large amounts of bread made her feel sick! Now she eats bread in moderation and she feels okay :)

I own restaurants. I have to force myself to not roll my eyes at the numbers of people who come in with growing fear of gluten claiming to be allergic to it. One parent even asked us to prepare one child's salad with separate utensils to avoid even the slightest contact with bread. Touching bread does not cause a reaction to gluten.

So I think we should distinguish between "gluten intolerance" (which is often self-diagnosed) and "celiac disease" (actual medical condition with allergic reaction to gluten). For people with the latter, even trace amounts of gluten are harmful:

https://www.ncbi.nlm.nih.gov/pubmed/1923558

Even inhaled gluten is enough to cause immune system reaction: https://www.nejm.org/doi/pdf/10.1056/NEJMc063112

The generally accepted safe threshold of gluten intake for people with celiac disease is somewhere on the order between 6 and 30mg (depending on the study). Even that may be high, there are case studies of individuals where as little as 1mg of gluten prevented recovery of their gut:

https://www.ncbi.nlm.nih.gov/pubmed/15497770

So the parent that asked for separate utensils is not insane; sharing a bread knife between gluten-free and gluten-containing bread can be harmful already.

(A close family member and another close friend of mine have celiac disease, and it is seriously not a joke)

A slice of bread weighs about an ounce or 28 grams. There is less than 3 grams of protein in a slice of bread. About 80% of the protein is gluten which gives 2.5 grams of gluten per slice. So at the lowest exposure level, 1 milligram, this would mean making sure not to eat 1/2500th of the slice of bread. The slice of bread is about 4 inches by 4 inches by 0.5 inches giving a volume of 8 cubic inches. 1/2500th of that slice is 0.0032 cubic inches or a cubic piece >1/8 inch on each side.

Based on the above calculation, I think it's probably ok to use the same utensil as long as there are no obvious crumbs.

Minor nit: celiac disease isn’t an allergy. It’s a very different underlying mechanism with very different effects.

For a child with celiac disease, eating even a few crumbs of gluten is enough to set off the auto-immune reaction and cause intestinal damage. I agree that a lot of the fear of gluten is overblown, but there are people for whom it really does matter.

Celiac disease isn't funny. Some people are sensitive enough that even the type of contact you describe transfers enough gluten (from the bread to the plate to the actual food consumed) to set off a reaction. I have several friends with celiac, and one of them was recently hospitalized after a restaurant server decided to "test" their claim about having celiac. That server has since been fired by the restaurant and facing assault charges; her (now former) employer is looking at a pretty heft lawsuit.

Please let us know what those restaurants are so we can avoid them, and any future restaurants you own.

Perhaps you should consider a different line of work? One in which you aren't in a position to serve people food that can make them seriously ill. Either that, or perhaps accept reality and choose to not be condescending and flippant toward people who have genuine concerns for their health.

Agreed, this flippant attitude is more toxic than people trying to look out for themselves in a world where even the Food Pyramid is bullshit.

Well, I can't say to what extent people are actually intolerant to gluten or not.

But it is clear that sourdough DOES break down gluten during fermentation. Here's a lucid observational demonstration of that ...

(https://www.youtube.com/watch?v=vsCpdCsJFr4)

-- it's in French, but they have really good bread making videos.

Depends on where you'd get your bread otherwise I assume, what has been added to it, where the flour is sourced from, how it was grown. Those last factors also matter for your own bread obviously. I'm not sure how conclusive the science is on the effects of using the different types of pesticides on crops, or none at all, on the final product, and how that in turn affects health.

Probably very negligible as the baking should kill all microbes present (some might sporulate but probably not a relevant number). But Sourdough bread is super tasty so don't stop doing it!

The article is in regards to sourdough microbes that are on a bakers hands, not necessarily those that may or may not survive the baking process.

I have a feeling we'll found out that it's things like bacteria found in boogers, sweat, ect, that make the best bread.

Lactobacillus is omnipresent in our bodies, from our stomach to our boogers, and is the main lactic acid bacteria used in sourdough bread and quickly brewed sour beers.

Most bacteria in boogers and sweat is pretty harmless stuff, and a lot of it can be used to metabolize some tasty compounds. Even some clostridiums (same category of bacteria as the disease c. difficile and an omnipresent type of bacteria in our stomachs) are used to produce esters in rum.

Dang I'm drinking a sour as I type this...

Dovetails with the history of industrial white bread marketing push first half of 20th century - sterile mechanized factory vs. dirty small bakeries where those darker skin immigrants, like Italians, make your bread with bare hands.

This industrial quick rise, yeast plus extra sugar instead of yeast slowly feeding of carbohydrates from the grain, white bread one can connect to the host of modern days autoimmunes and digestive issues.

To be fair, I think digestive issues with commercial bread vs sourdough has nothing to do with the bacteria - baking sourdough kills bacteria - but the slow fermintation that lowers phytates in sourdough and makes it easier to digest.

Terry Gross interviewed him on Monday's Fresh Air: https://www.npr.org/sections/health-shots/2018/11/12/6669336...

I enjoyed it.

Seems intuitive but I wish there was a little more detail on their protocol, e.g. did they check who had washed their hands when, how long do the bacteris stay, etc.

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