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Accidental Sourdough Starter

bwraith's picture

Accidental Sourdough Starter

As I conducted my home ash content tests during the latest home milling and sifting session, a sourdough starter was accidentally started. The home ash content test involves mixing 5 grams of flour with 100 grams of distilled water, stirring it periodically, and measuring the conductivity of the water until it stabilizes, about 24 hours later. All of that time was spent at about 69F, the temperature of my kitchen in the winter. I noticed a familiar smell, something like yogurt, that was reminiscent of the early stages of some of the starter staring experiments I have conducted in the past. The pH was measured and, sure enough it was around 3.4 for all the jars I was testing, even though the jars had various flours including Heartland Mill AP, Golden Buffalo, and whole wheat, as well as various flours from my milling and sifting experiment.

Since the jars appeared to have fermentation activity in them, I decided to give a try at starting one up. After stirring up the slurry in the Golden Buffalo jar, 20 grams of it was mixed with 30 grams of flour to form a fairly firm dough, which was then placed on a shelf above my coffee machine with a temperature of about 79F. It was left there for 24 hours at the end of which it had risen slightly in volume and still had a bit of a sour milk or yogurt smell.

The culture at the end of 24 hours (48 hours from when the first 5 grams was mixed with water) was fed again by taking 5 grams of the culture and mixing it with 22g or Poland Springs water and 28g of KA AP flour. It was placed at 79F above the coffee machine for another 24 hours, and the result was that it had doubled in volume and was beginning to smell more tangy and vinegary like a typical mature sourdough starter. The consistency was a little runny with small bubbles, but it clearly seemed a little closer to a ripe, healthy sourdough starter than it was the day before.

The culture was again fed the same way and returned for another 24 hours to the 79F shelf above the coffee machine. It had risen by about 4x, smelled like a normal sourdough starter, and had the usual consistency of a somewhat ripe firm sourdough starter.

I'm sure it is ready to be used to make some bread. After starting so many of these starters in the last few years in various experiments, I know what a healthy one is like. It went so smoothly, it seemed worth mentioning, as it is a little different from the usual recipes.

To summarize this accidental process:

Day 1:

Mix 5 grams of very fresh whole wheat flour (or maybe white flour, as the Heartland Mill AP smelled much the same, though less intense) with 100 grams of distilled water (saves any trouble with chlorine, alkalinity or other problems with water), stir, and let sit, covered, at room temperature (I imagine at 79F would work, too) for 24 hours, stirring or swirling periodically.

Day 2:

Stir up the water and flour mixture and take 20 grams of it and place in a clean jar. Add 30 grams of white flour, stir into a thick paste or a firm dough, and let sit at around 79F (probably room temperature would also work, though it might take several more days, depending on how cold it is) for 24 hours.

Day 3 and beyond:

Feed the culture by taking 5 grams of the culture, mix with 20 grams of water and 28 grams of white flour. Let sit for 24 hours at 79F.

Probably you don't need distilled water anymore, in fact it may not be needed at all at the beginning either. It may be good to avoid chlorinated water. I use bottled water without any problems, but my well water is surprisingly alkaline and it seems to have been the cause of some problems with starting starters I've experienced in the past.

The culture should be ready when it no longer turns runny after rising by more than about 3x and has large bubbles in it if you cut into it with a spoon. With the feeding above, it should rise by more than 2x in about 4.5 hours at 79F, about 5.5 hours at 74F, or about 7.5 hours at 69F.

It might take several days longer, but this worked for me faster than any method I've tried in the past.

I suppose it's just a lucky but rare event, but it seemed like every single jar in all these home ash content measurements I've been doing have a very similar smell after 24 hours. I wouldn't be surprised if any of them would have started up by just feeding them.

It's also possible that some sort of cross contamination with my active starter occured, except I did these by mixing distilled water poured from a container that I believe couldn't possibly have had any contamination from my active starters. Also, I only stirred by swirling the jars and didn't use any stirrer or whisk. I did use a fork on subsequent days, but that fork had been through the dishwasher and never used to stir my active sourdough starter. I suppose the jar I used may have somehow had some residue of an active starter in it, but I had recently thoroughly cleaned the jars used in these experiments with soap and hot water.

Anyway, I'd be curious if anyone else gives this a try and it works for them, if you're curious to try it. The things that's a little different about this method from what I've read about or tried in the past is the very high initial hydration (2000%) at room temperature followed by immediate conversion to a firm white starter at a fairly warm 79F. I wonder if there is some unexpected advantage to this method.


KipperCat's picture

An interesting concept - I'll give it a try when I'm ready to make another starter. It's wonderful how quickly it matured!

There is one type of cross-inoculation that may have happened. I don't know how soon you did these tests after milling flour. Is it possible that a slight amount of flour from your fresh wheat was in the air and settled on the other samples? The only reason I ask is that I would expect freshly ground whole wheat to have more wild yeast than packaged flour - but I really don't know if that's the case.

bwraith's picture


Yes, you are probably right. I wouldn't be surprised if some amount of dust from my freshly milled wheat made it into the Heartland Mill flours I was also using in the ash content tests. I loaded the jars up in the kitchen away from my mill, but it is true that I had my Heartland Mill and home milled flours all sitting in a few buckets and was spooning the flour out into each sample jar with only a wiping off of the spoon each time, not an actual washing with soap and water.

I guess from my point of view all those flours are very similar, in that I was milling organic milling wheat from Heartland Mill that is probably essentially the same product they use to mill the Organic Whole Wheat Flour and the Golden Buffalo flour. Basically, all those samples with 5g of flour and 100g of water developed a pH of around 3.4 and a sour milk aroma after 24 hours at a cool room temperature of around 69F. The freshly milled wheat berries may have contributed some, but the Heartland Mill AP, Golden Buffalo, and Whole Wheat, and my home milled samples all consistently developed the same pH and aroma after 24 hours. This has happened in three successive sessions of ash content tests, too.

Maybe I should try the same thing with some KA AP, KA organic WW, or Wheat Montana Bronze Chief flour. Maybe I'm jumping to conclusions, but it was amazing how consistently the samples developed the same smell and pH in all these tests.

So, I'd be very interested to know what happens if you try this method. I imagine the distilled water is not so important, especially if you know that the water source you use has no problems with "starter starting".


vistawinds's picture

Hi Bill,

I love your posts. They have encouraged me to try a sourdough starter-AGAIN! I have been reading and realize the first two or three recipes I had were, silly. Now I believe I have a better understanding of the process. Now for your advice, oh sourdough gooorooo- I moved to Ireland. This house is either freezing cold, or when the heat is cycling, its quite warm. There is no thermostat. Average temp w/o heat on is 60 or below. "Stupid" oven in house, light only comes on when oven is in a heat mode. However microwave has a light, and can maintain a consistant 85. I have a heating pad and wonder if I shouldn't make a "proofing box" of sorts to maintain an enviornment, just for my sourdough starter? What is the ideal temp for the starter? Your thoughts would be ever so much appreciated. 

Thank you,

Alison- missing true sourdough bread 

bwraith's picture


To start a starter, I think 80F is ideal, although for the first day, some argue 65F to 70F might be good to discourage spoilage bacteria from getting the upper hand. That's also why pineapple juice or OJ is used on the first day in certain recipes, such as Sourdolady's recipe that has been shown to be very reliable. A temperature of 85F in your microwave might work, but it's a bit on the warm side and may cause some problems.

Once the starter has started, the room temperature maintenance is best done somewhere between 68F and 82F. It isn't as convenient to use 80F once the starter is healthy, unless you want to revive it from refrigerated storage more quickly. If you maintain the starter at room temperature all the time, cooler temperatures are more convenient because you can feed less frequently.

Having said that, below about 68F it's possible to maintain starters and make sourdough bread, but things will take much, much longer, and flavors may be different, sometimes good, sometimes not so good, depending on the recipe.

So, yes, I would say that if you consistently have temperatures below about 68F, then it is probably well worth figuring out a "proofing box" of some sort. If you do make something, it's worth trying to make it big enough to accomodate the largest breads you are likely to make. For example, a focaccia on a jelly roll pan can be frustratingly just too large for typical coolers or storage boxes one might use for a proofing box.