The Fresh Loaf

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Is my starter a sourdough starter or a commercial yeast starter?

ade100's picture

Is my starter a sourdough starter or a commercial yeast starter?

Hello everyone!

I recently got hold of some new sourdough starter and I've started thinking the person that gave it to me might have been wrong about it's origins. It rises super fast, even in the fridge, makes hooch but doesn't taste at all tangy. The person that gave it to me said it's from Italy and made using fruit juice. 

Are there any signs that differentiate a sourdough starter from a commercial yeast starter?

I wouldn't want to throw away a perfectly good sourdough starter that might just be different from what I usually experienced. 

Thanks a bunch and have a great day.

(Also, baked a bread using it, rose perfectly)

Abe's picture
Abe (not verified)

A common question on this site is "how does one make a more tangy bread using sourdough starter"? Sourdough doesn't necessarily equate to a tangy bread. Lack of tang doesn't mean your starter isn't sourdough!

The only fruit juice i've heard being used to make a starter is something acidic, like pineapple juice, to kick start a sourdough starter being made from scratch. This info seems to work in your favour.

Let us say, for arguments sake, it was made from commercial yeast. I'm not 100% certain but have heard that over time it'd take on the characteristics of a sourdough starter.

So bearing all this in mind i'm going to say you have the real deal. What you can do is taste the starter. If indeed it is a sourdough starter you'll soon know about it. Stand by the sink with a teaspoon in your hand and a glass of water at the ready. You can also try and manipulate the tang of the resulting bread by using the starter when it's more mature. So feed your starter, allow it to peak and use when it starts to fall.

ade100's picture


Thanks for replying. So lack of acidity/tang even in the raw starter, after it has made hooch, is normal?

Abe's picture
Abe (not verified)

I would have thought that the presence of hooch would mean more acidity/tang. Are you assuming there's lack of acidity/tang in the starter because of the taste of the final loaf of bread or have you tasted the starter? There are a lot of factors to take into account when aiming for a tangy loaf. Not only how you keep your starter but also how it's used within the final dough. From maturity of the starter, type of flour, temperature, percentage of preferment etc. Having said all that even a yeasted preferment, or dough, that's been over fermented will give off a stronger more alcoholic taste and take on "some" characteristics of a sourdough. Question is if it's hooch or not. Is the liquid on top of the starter? Is it clear or murky?

Trying to think of an experiment to establish if it is indeed a sourdough starter. The only one I can think of for now (hoping others will chime in here) is for you to make a simple dough as follows:

  • 50g bread flour
  • 30g water
  • 1g salt
  • 10g starter

Knead into a dough ball and fully develop the gluten, 10 + minutes. Get it to a point where it's not sticky anymore and it has a nice smooth skin. Leave to ferment in a warm place and observe.

If it is indeed a sourdough starter it should effect the gluten differently to a yeasted dough. As the dough ferments the gluten begins to break down. I do believe that given time another process will do the same thing to a yeasted dough but that takes a lot longer. See what happens to the dough and how long it takes before the dough ball has no strength left in it with the starter attacking the gluten reducing the dough to "mush".

Now because even a yeasted dough will rise, peak and fall try re-kneading it back into a dough ball each time it has peaked. I'm thinking a yeasted dough will take on it's original form quite easily a few times whereas you'll notice that a sourdough starter risen ball of dough will become more and more sticky eahc time.

Take notes/photos and report back.

BobbyFourFingers's picture

“The only fruit juice i've heard being used to make a starter is something acidic, like pineapple juice, to kick start a sourdough starter being made from scratch.”

One of the classic French ways to make a sourdough was to make a wine from grape juice, specifically utilizing the yeast on the skins for fermentation. The must was strained from the young wine and the wine was added to flour. The wine’s yeast was the primary yeast for the starter. The starter was cut and fed with water and flour daily afterwards.

One of my posts in this thread goes over using plum wine in place of grape wine. It still needs to develop LAB/AAB, but the process does not perform the same function as the pineapple method.

The pineapple method is used fo suppress gassy bacteria whereas the fruit wine method is used to inoculate the flour paste with an overwhelming amount of yeast immediately.

Capn Dub's picture
Capn Dub

Sourdough is called “sourdough” because it contains lactic or acetic acid, or both.  Acids taste sour, so give the starter a taste.  If you taste the acid, then it is sourdough; if not, then I dunno — maybe is, maybe isn’t, but I don’t see how any starter can mature without gaining the bacteria that generate the acid.

Mini Oven's picture
Mini Oven

Gee y'all,  anytime you are making a loaf without purchased commercial yeast, and it eats carbs, and raises your buns, it's a sourdough! 

There are many varieties of sourdoughs as what you have in the starter are colonies of may yeasts and bacteria working together.   Some more, some less.  There are different kinds of "sour" too.  :)