The Fresh Loaf

News & Information for Amateur Bakers and Artisan Bread Enthusiasts

Effects of salt on fermentation and proofing

SourFlour's picture

Effects of salt on fermentation and proofing

I have often heard that salt interferes with the yeasts ability to consume flour, and therefore leads to less active fermentation.  I assume that this is the reasoning that sponges are often made without the salt, and only at the final stage before shaping your dough is the salt added.

Does anyone have any experience with trying salt during bulk fermentation, and noticing any differences? If salt does indeed hamper the yeast, I assume you could either use a larger percentage of starter, or a more active starter.  If it doesn't have much of an effect, I would just as well start adding it in the beginning to keep my formulas simpler.

Thanks for the help.

Danny - Sour Flour

ericb's picture


You have the right idea: salt should generally be mixed in with the sponge (or poolish, starter, etc.), flour, yeast, and water prior bulk fermentation. I have never seen a recipe call for adding salt to the dough just before dividing the dough. I would expect that the mixing required to do this would destroy the gluten structure built up in the primary fermentation.

You're also right about salt slowing down the yeast. A dough without salt would not only taste bland, but I suspect that fermentation and proofing would be very short. The yeast would go crazy, exhausting their food source before giving the dough a chance to develop properly.

Could you share with us the recipe that you're working with?




SourFlour's picture

Hi Eric,

I guess I have confused some terms around a bit, but the same concepts apply.  I am actually talking about adding salt into the creation of the sponge from my starter.  The general formula that I use is adapted from Joy of Cooking, but also what I have seen in other sourdough formulas:

- Mix in proportions of 3:3:2 (starter, flour, water) to make a sponge.
- Let sponge sit for 4-8 hours
- Add salt and a bit of extra flour (to get your hydration to the level desired)
- Knead dough (or french fold, or stretch and fold)
- Shape dough and proof

My question is what the effect is if I add the salt before the sponge sits for 4-8 hours.  I will eventually start to experiment with this, but I havn't yet.

When you hypothesize that "the yeast would go crazy, exhausting their food souce", I guess my question is just how big is the effect for any given salt percentage.  Does 2% salt slow yeast growth by 15%? Would .05% have any slowing effect?

Thanks for helping me to think about this.

Take care,
Danny - Sour Flour

subfuscpersona's picture

If you're seeking a way to simplify the process of making a straight-forward sourdough loaf, you need look no further than Susan's blog right here on TFL. She just mixes her sourdough starter with all the other ingredients (including salt) at the beginning. 

I believe she uses a firm starter (? 74% hydration ?) rather than a more liquid one, so if you keep your starter at 100% hydration you would have to make that adjustment first.

Her bread photos are ample testimony that her approach works.


wally's picture


I'm with Eric and eviltigerlily about adding salt at that point.  If all else you're adding is 'a bit of extra flour' then I'm assuming the dough is fairly developed and it's going to be difficult to incorporate the salt throughout.

Salt does slow the activity of yeast by slightly de-hydrating it.  However, it's not harmful to the leavening process.  If your recipe calls for the dough to sit for 4-8 hours without salt, you're adding a little additional time perhaps, but nothing significant.  In fact, a potentially larger factor is the temperature of the room where the dough is undergoing its bulk fermentation - a warm room may offset the effects of the salt, whereas a cool one would probably multiply them to an extent.

During the hot summer months here in DC when my kitchen gets quite warm from the sun, I've taken to adding 1% salt to my starter to retard it.  Otherwise, it ferments too quickly.


SourFlour's picture

This explanation is pretty much what I was thinking.  It would be interesting to calculate exactly how much more time you need, or what altered temperature you need to adjust for adding in a given amount of salt. It seems like it is fairly small, but perhaps for weaker starters the effect might be multiplied, while in stronger starters it might almost not affect it at all.

Thanks again for giving me your experience.

Take care,
Danny - Sour Flour

Mini Oven's picture
Mini Oven

try a search using: 

salt concentration on dough fermentation

Me?  I would start with 3.5 or  4% salt to flour and see what that does to the fermentation.