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Influence of fortified flour on sourdough starter?

September 25, 2023 - 4:33am
JPhillips's picture
JPhillips

Influence of fortified flour on sourdough starter?

Hi there -- I recently moved to the UK and have noticed that all of the flour here is (by law) enriched with calcium, iron, niacin and thiamin. Does anyone have any experience or thoughts on how this should affect my starter? I mostly ask because it has become very vinegar-y smelling after moving, and I'm not sure if this is the water or the flour. It's easy enough to buy imported flour, but before bothering with it I was curious if any other British bakers have some insight into this. 

Thanks!

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Abe's picture
Abe
Sep 25 2023 - 4:54am

And have had no issues with fortified flour. I would imagine it's the opposite. Vitamins and minerals are good for you and they will also be good for the yeast. 

tpassin's picture
tpassin
Sep 25 2023 - 5:43am

White flours are fortified in the US for the most part.  I haven't had any particular problems with my starters.  US white flours also often have malted barley or some equivalent enzymes added to promote yeast activity.  

Abe's picture
Abe
Sep 25 2023 - 5:47am

Then it's also fortified for the yeast. It can only do the yeast good. And added malt too would be even better. Perhaps it was the move. Unfed for a while and possibly different water. I think a few healthy feeds should do the trick. 

JPhillips's picture
JPhillips
Sep 27 2023 - 1:14am

I'm still a bit sceptical about what the fortification does. As with most nutrients, too much can be bad for yeast and start to inhibit at higher levels, e.g., as in this study on calcium and yeast, and humans and yeast certainly don't have the same dose-response curve so what's good for humans need not be best for yeast. But I'll experiment with some flours and see what the differences are. 

Abe's picture
Abe
Sep 27 2023 - 3:14am

Works a treat. My starter has no issues with fortified flour. 

tpassin's picture
tpassin
Sep 27 2023 - 6:16am

Here are some quotes from Bakerpedia ("Yeast Nutrients")

https://bakerpedia.com/processes/yeast-nutrients/

Vitamin B7 or Biotin: It Increases rate of yeast growth as well as its fermentation. A lack of biotin in yeast leads to undergrowth.  The most significant role of biotin, however, may be its involvement in the synthesis of adaptive enzymes necessary for sucrose fermentation.

Bakers may opt to use yeast nutrients in no-time dough production runs where fermentation must take place at a high rate. Yeast nutrients are usually not needed for the production of artisan bakery products that involve long fermentation stages. 

Yeast nutrients are not strictly necessary in all bakery products. Ingredients such as wheat flour and milk solids, can provide sufficient amounts of nutrients for proper yeast function. under non-ideal conditions, yeast nutrients may be added  to enhance yeast activity.

It appears that many yeast nutrients are used in the production of commercial yeast, and here is a very technical review of the roles of vitamin B family compounds in yeast metabolism.  It's way too technical for most of us, but it does indicate that the B vitamins play an important role in yeast metabolism, specifically S. cerevisiae:

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7187267/

These articles support the idea that typical fortification of white flour in some countries may be helpful for yeast growth, and at any rate not harmful.

For what it's worth - always uncertain - here is a shortened ChatGPT transcript:

Prompt
=======
act as an expert in bread baking and yeast, briefly say what effect the addition of vitamins to white flour has on the growth of yeast in bread made from that flour.

ChatGPT
========
The addition of vitamins to white flour can have a positive effect on the growth of yeast in bread made from that flour. This is because vitamins, particularly B vitamins such as B1 (thiamine), B2 (riboflavin), B3 (niacin), and B6 (pyridoxine), are essential for yeast metabolism.

 

JPhillips's picture
JPhillips
Sep 29 2023 - 1:34am

Interesting read. I don't deny that yeast likely need these nutrients to some degree, my questions is moreso about whether the addition of more of them starts to inhibit growth, which is must at some point. And also for sourdough it's as much about the balance of bacteria-to-yeast. So if the bacteria are much more calcium limited, for example, then adding more calcium could least to a bacteria explosion relative to yeast. 

Anyway, thanks for the info.