making starter with dry yeast


I have cheated a little and started my starter with a little bit of commercial dry yeast. I had some dry yeast from the last batch of bread that I baked. I added it to water. I left the water sit for a couple of days. Then I started adding flour to it, a couple of days later when I checked the jar it was full of bubbles on the top. I have added equal measures of water and flour to my 'starter'. But I am not sure if this starter is safe to use, considering that I cheated and started this with dry yeast.

How can I know if this is a safe starter to use?


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farinam's picture
farinam 2012 September 5

Hello Alas,

You don't say how long you have been developing your starter other than a couple of couple of days.  If you haven't read SourDom's beginners Blog on this site, then I recommend that you do.

If the starter is acting consistently after every feed and is not smelling odd or really bad then it should be fine to use.  The fact that you have used commercial yeast to start with is of no real consequence as it will be replaced by wild yeasts and bacteria as the sourdough develops.

Let us know how you go.


davo 2012 September 5

I have read that if a commercial yeast culture is left for long enough, it will eventually develop some lactobacillus and wild yeasts will start to dominate the commercial one. And in the meantime it will be active from the commercial yeast. However, I'm not sure it's actually a short cut to a sourdough culture. This is because - as I understand it, commercial yeast feeds on maltose (a disaccharide produced from damaged starch by the amylase enzymes), as do lactobacilli. Wild yeasts predominantly do not utilise maltose, but do utilise the mono-saccharides that are broken down from the maltose by lactobacilli. This might all be mumbo-jumbo, but I did read it in a paper (unless I'm mis-recalling the detail).

To cut a long story short, wild yeast will set up symbiotically with lactobacilli because they are complementary rather than competitive in terms of food source. Whereas commercial yeast will compete with lactobacilli.

So basically, while it eventually will switch over, for some period it's really just a commercial yeast culture, that isn't ideal in conditions for the lactobacilli that make sourdough distinctive from commercial bread.

Whether you will get to a stable sourdough quicker by one path rather than the other I don't know - but it strikes me that if you really want sourdough, why not just go straight there? My (perhaps poor) analogy is that it seems at least a bit like starting out eating meat in order to eventually by degrees become a vegetarian.

It will make bread straight away, so that's an advantage, but I'd be unsure when you could be sure that you are making actual sourdough. Maybe if that doesn't matter it really is the best path to take.

chazzone 2012 November 4

Don't stress on your starter.  I kept a "sourdough" starter for years that I started out on commercial yeast.  It'll be fine, and likely make some damned fine bread.  

But now that this new fangled internet has come along, and we have cool stuff like thie Sourdough Companion online, we have lots more options.  So, why not use the starter you have, and make another one following ol' Sourdom's directions.  It'll work out fine, and you can get into the process, and be baking in the mean time. 

I keep 3 starters going, and they're each a little different, so adding another is really not a big hassle.  

Just sayin',

Happy baking,



Merrid 2012 November 5

Safe? I'd say so, but what you have at the moment is really more of a paté fermentée than a sourdough culture. It will make nice bread, but it won't be sourdough until you have a sourdough culture.

Graham's picture
Graham 2012 November 5

Hi Alas.

You could try to increase the acidity of your brew, making it favour sourdough yeast over commercial yeast. Sourdough yeasts and bacteria are more acid tolerant than commercial yeast. You could go to the trouble of measuring pH, aiming for a range of 3.8 to 4.5, or make a rough estimate.

Leaving your existing dough to ferment beyond its comfort zone, or adding (say) lemon juice are methods of increasing acidity and making the environment less attractive to commercial yeast. 

Feed using a quality Organic wholemeal flour to increase the likilyhood of sourdough yeasts and bacteria moving in when the commercial yeast moves on. A proportion of rye is recommended. The most recent research suggests that sourdough organisms come mostly from the flour, rather than the air (with the possibility that they are also transferred from your spit or skin).

I think that there would be a fair chance that during the transition stage your brew will appear to die completely...go flat and lifeless. Keep stiring or kneading daily and eventually it should come back to life.


Some related reading:

a classic from 1970/71:

2003 interview with one of the paper's authors:

and a 1976 paper:

Stefen Tradtion... 2012 November 5

Why not just make a sour cutlure? It is not hard to do.  Then you will have aan authentic sourdough culture.

As Merrid correctly pointed out what you have is a paté fermentée 

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