I have a sourdough starter (rye flour based) that is quite active and I use it a lot.

I decided to make bread today and used AP flour instead of bread flour on purpose. I wanted to see what would happen. Turns out, not much is happening and the dough is not very active and not rising much. I wanted to bake it in a few hours. Assuming it doesn't pick up the pace by then, can I add instant yeast to it to at least get some rise out of the bread? I don't really throw out all that flour and it smells sour so I think some flavor will be there.

Or am I better off leaving it overnight to give the starter more time to work on this dough?

  • I don't know enough to answer, but I've had similar experiences when I feed my starter with a different brand of flour. It seems like the bugs need some time to adjust to even a slightly different food source. It seems like your situation is different though? But I recommend patience, and next time, take some of your starter and feed it with the flour you'll make the bread with a day or two in advance to avoid this kind of thing. (Patience makes for tastier bread anyway.)
    – kitukwfyer
    Apr 5, 2020 at 1:50
  • @kitukwfyer yeah I usually bake with the other flours, and it works fine. Im probably just gonna stick to whole wheat. I did bake this one (just now) and it turned okay, but very sour even for a sourdough. Its good but different for sure.
    – Catsunami
    Apr 5, 2020 at 5:59

3 Answers 3


Yes, you can add instant yeast to a sourdough. However, the fact that you used AP vs bread flour should not have much to do with the fermentation activity. The different flours have different protein contents, which impact gluten development. Certainly, allowing it to ferment overnight is an option, but if you are short on time you can use an instant yeast to speed things up.

  • Thanks! I just finished baking it (let it proof until 11pm even though I was supposed to bake it around 3pm today). Its very sour, it didnt have much of an oven spring but its quite tasty and soft. Not sure what was up with this bread... I always bake with either whole wheat or dark rye flour, so the AP flour was the only variable that changed. The dough also felt odd and very sticky, perhaps in my tired slumber I overhydrated it.
    – Catsunami
    Apr 5, 2020 at 5:56
  • Different flours certainly impact hydration.
    – moscafj
    Apr 5, 2020 at 11:08
  • The very sticky aspect makes me think your bugs went to town too fast actually, opposite of my problem above. The longer sourdough sets and is devoured, the stickier it gets. Maybe the apf without bran and such was too easy to digest? Funky.
    – kitukwfyer
    Apr 5, 2020 at 13:16
  • @kitukwfyer, yeah it's really odd. I've never experienced bread dough this crazy sticky (I always make the same bread, so same measurements, etc). The flavour makes me feel it went too far as well. I might experiment with this again and just pay some more attention to it at the early stages.
    – Catsunami
    Apr 5, 2020 at 19:39

I would let it prove overnight in the fridge rather than adding instant yeast which is a different variety of yeast that will be competing with your sourdough yeast.


You could also move the dough somewhere warmer, which will help the yeast grow. Perhaps cover it with plastic film wrap to keep the heat inside the bowl (rather than say a cloth). Yeast generates a little heat on its own too. Many electrical devices generate excess heat, that can be used as a warm place - like the top of your refrigerator, near the cooling-grill at the back.

Also you could feed the yeast with a little honey or sugar.

If you have instant yeast, I would leave the sour-dough starter to take as long as it takes, and simply make another bread in the meantime with the bread making yeast. Sure it's not sour-dough, but tomorrow you can make "proper" sour-dough!

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