The Fresh Loaf

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Has anyone ever cultured commercial dried sourdough starters in a sterile environment?

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DeWitt's picture
DeWitt

Has anyone ever cultured commercial dried sourdough starters in a sterile environment?

I'm really curious as to whether these dried powders actually contain what they say they do.

The other question would be, shouldn't they be revived in a sweetened slightly acidic medium rather than just flour and water, i.e. some variation on the pineapple juice solution?  I'm going to try that with a couple of samples, but it won't be completely sterile.

Pioneer Foodie's picture
Pioneer Foodie

Ed Wood claims that his exotic cultures maintain their original distinct qualities even over time. I have a friend who affirms this of Wood's cultures. But Reinhart in BBA says that exotic cultures will assimilate to local bacteria over time. Is this what you're asking? Wood seems qualified to make the claims, but he's the one selling. I don't have enough experience to know one way or another.

DeWitt's picture
DeWitt

It's not the culture distinctions so much as the presence of cultures at all.  I read a lot of comments about people failing to get dried starters to activate.  The longer it takes, the more likely it is that if it does ever start, it's from local wild yeasts.

Boron Elgar's picture
Boron Elgar

I have not tried a sterile environment, but I have done  revivial of a 35+ year old Sourdough Jack packet side-by-side with a start-from-scratch flour and AP flour mix and gotten distinctly differnt starters out of them. I have done this more than once.

And as someone who keeps 4-6 starters alive at any one time, each distinct in rise time and behavior (cannot vouch for precise bread flavor diffs, though), I tend to side with Ed Wood over Reinhart - but that is no surprise, as I've always though that pineapple juice was more appropriate in a pina colada than in sourdough starter.

 

Boron

DeWitt's picture
DeWitt

I lost my original Sourdough Jack cookbook somehow but managed to find one on eBay.  I was never able to make very good bread using his recipe, but back then high gluten bread flours weren't on your average supermarket shelf and retardation in the refrigerator was only known to professional bakers.

I've found that diluted vinegar (anywhere from 1:10 to 1:40) works quite well in a start from scratch starter mix.  A little honey as well seems to speed things up too.  That way you're not adding much of anything that won't be there eventually anyway, acetic acid from the vinegar and glucose and fructose from the honey.  Pineapple juice is about 10% sugars.

Pioneer Foodie's picture
Pioneer Foodie

Sausage and cheese suppliers for home crafters also sell dry powdered cultures doing cured processes using bacteria. Those seem to do their job reliably.

DeWitt's picture
DeWitt

Those are bacteria, not yeast.  From the description of failed attempts at reviving dried starter, the bacteria are probably there, but the yeast may not be.  I'm not saying it's impossible for a dried sourdough culture to be viable.  I'm saying that I haven't seen all that much good evidence that they are.  For example, there's this note on reviving dried sourdough starter.  He uses rye flour and doesn't see activity until the second day.  Since it's possible to use just rye flour and water with no dried starter and see activity on the second day, especially since the dried starter will contain lactic acid to acidify the mix, that is not evidence that the dried starter was viable.

I'm playing with a commercial dried starter right now.  I'm soaking a small amount in water sweetened with honey and acidified with a small amount of vinegar.  The larger pieces of dried starter are like little bricks.  After 1/2 hour, there was no evidence that they were softening enough to disperse, much less get wet enough that any yeast would become active.  Commercial yeast, admittedly much higher concentration, would be bubbling away like mad at that point.  Another thing I'm going to try is use a mash as the substrate for reviving a dried culture.  Any yeast in the flour used to make the mash should have been killed by the high temperature used to make the mash.

Since the wild yeast and lactobacilli are symbiotic, it's not at all clear that you have the same culture, once it does become active, if you have to add your own wild yeast in, for example, whole grain rye flour.

DeWitt's picture
DeWitt

I made a whole wheat mash using Reinhart's method in Bread Baker's Apprentice.  Well, not quite.  His instructions for an oven that can't be set to 150F, off 10 minutes then on 10 minutes for an hour, would have kept my oven at very close to 200F.  It took over half an hour to drop from 200F to 145F (type K thermocouple thermometer).  Turning it back on until the measured temperature was above 150 was good enough for the next half hour.  Two hours later it was still 110F.

Anyway, I currently have samples of two commercial dried sourdough starters.  I took 1/2 teaspoon of each, added 1 tsp water and allowed to soak for 30 minutes.  Then I added 50 g mash to each starter and 50 g mash and 1 tsp water in another vessel as a control.  All went into an 80F proof box.  Twelve hours later, nothing.  Oh, but it takes at least 24 hours to get activity, you might say.  In 24 hours with raw whole grain flour, I can get activity without adding a dried sourdough culture.

I'm beginning to think people are fooling themselves that simply air drying an active sourdough starter leaves viable organisms in the dried material.  Obviously it is possible to dry a yeast culture and keep it viable.  Commercial dried yeast, whether active dry or instant, clearly works.  If I take water sweetened with honey and add a small amount of instant yeast, I can smell the alcohol in a few hours.  Dried sourdough starters, not so much after two days.

I have another sample of commercial dried starter on order.  I'm seriously considering writing a note to the FDA suggesting they investigate the possibility of false advertising if I continue to get negative results.

If anyone out there is still reading this and has some dried starter of their own, please try this experiment:  Activate your dried starter using your preferred method, but run a control using the same amount and type of flour and water but no dried starter.  Treat both exactly the same, same temperature and same amount of stirring (use different mixing implements of course).  Please post your results positive or negative. I suspect, though, that anyone who does a lot of sourdough baking has enough organisms in the air to create a new starter so they'll see activity in both.

All at Sea's picture
All at Sea

... worked fine for me. I spread some starter out thinly on parchment, floated another piece of parchment over the top to stop flies or dust contaminating the smeared starter sample. And left to dry out on a very sunny windowsill in the boat. Then folded the parchment spread with starter crust (it was a very thin, flaky kinda crust) and popped into a sealed bag, smooshing the air out of the bag as much as possible. Took home to UK.

Revived it by flaking it into a cup - very thin flakes by this stage, adding tepid water (tap) and left it a few hours. Then threw in some flour and stirred. 24 hours after first rehydrating it, the wild yeast was off.  Couldn't have got such a fast result if there wasn't already some viable starter culture, I think. (However, my attempts at freezing starter and later reviving it were aun unmitigated, dreary, miserable failure.) 

I've never bought a dried starter (or any starter come to that) - nor am I likely to, so no experience with commercial offerings. But I take your point that if the rehydrated starter is sluggish to get going, how do you know whether it is the dried culture now getting active, or simply the wild yeast content of the flour added to get it going?

All at Sea

 

 

Toad.de.b's picture
Toad.de.b

Hey AaS,

Thanks for that simple starter drying/transport method.  I'm headed to the UK to visit family in a few months, and they've asked how my "children" are doing (read: SD cultures) and will I be bringing them along so they can "play" (read: raise bread) there.  The answer is yes, and now I know how.  Just hoping customs doesn't get too curious about this parchment paper packet in my case...

Tom

 

DeWitt's picture
DeWitt

The dried starter from sourdoughbreads.com seems to be active.  The mash became lighter in color and expanded in volume because of bubble formation.  I've started a regular feeding cycle to see what I get.  Still no activity from the other dried starter or the control.