The Fresh Loaf

News & Information for Amateur Bakers and Artisan Bread Enthusiasts

how do I substitute wild yeast starter in recipes calling for commercial yeast?

hsmum's picture

how do I substitute wild yeast starter in recipes calling for commercial yeast?

I'm sure that this question must already have been answered many times on this forum, but I can't seem to find it.  If it's easier, please just point me in the right direction! :)

I've been working with my wild yeast sourdough starter for a few months now, and I just love it.  I would now like to try my hand at using it in recipes that call for commercial yeast -- a sort of substitution.  Partly for frugality, partly for fun, and partly for health (so far so good in my immediate family, but diabetes has hit some of my older relatives and so the discussions posted here about sourdough & blood sugar have got me thinking.)

I'm just not sure how to go about it.  I assume that at some point I would need to calculate in baker's percentages the weight of flour and water in my starter and subtract that and the yeast from the commercial yeast recipe.  But what about other ingredients from that recipe -- when should they be added?  Do I first create a firm starter from my sourdough culture and once that has doubled, do the math and add in the other ingredients, before the first rise (of the recipe)?  Also, other than the lengthened rise times, is there anything else that I should be taking into account?






dmsnyder's picture

Hi, Karen.

The short answer is that you need to do some math.

You want some portion of the flour and water in the recipe to come from your starter. You need to decide on the hydration of your starter and decide on the percentage of total flour in the recipe you want to come from your starter (25% might be a good number to start with). The rest is calculation.

I know this may seem a bit abstract, but that's the general answer. It might be clearer to you if you post a specific recipe you want to convert, then some one can show you how to do the calculations with concrete numbers. 


Dragonbones's picture

Hi Karen,

Yes, it sounds like you have the right basic idea. I've been experimenting successfully with this recently. The easiest, I think, is to use a 100% hydration sourdough starter, so when you do the math you can just divide in half conveniently. Let's say you have a sticky bun recipe like this (I just grabbed this from

as an example):

 560 g AP flour

140 g cake flour

280 g cold water

14 g instant yeast (preferably osmotolerant)

14 g salt

35 g milk powder

105 g (2 large) eggs

140 g sugar

210 g butter, cut into 1/2-inch cubes, softened

 Just take your flour total (700g here) and decide what % you want to replace with starter (say, 25%, as David suggests). So you want 1/4 or 700 (i.e. 175g) of the flour to come from starter. The starter is a 1:1 so that amount of flour means 175x2=350g of starter. Build your starter up to 450g or so, so that you have some left to propagate it, and when it peaks, take 350 of that (175g each being water and flour) to use in the recipe (to compensate, subtract 175g each from the flour and water in the recipe, leaving you with 385g AP flour, all the cake flour, and 105g of water. And cut the commercial yeast out.) Now just put the recipe together as normal, adding the starter at the beginning, then the other ingredients. I like to add the water first, especially if using a firmer starter, then I clench it in my fist repeatedly to soften it in the water until it's quite soft and breaking up, and then it's easy to mix the other ingredients in.

LeadDog's picture

I made some spreadsheets up that might be helpful to you in calculating the bread formula for the conversion.  David's suggestion of 25% is one that I use a lot.  The range outside of 25% that I seem to use most often is 20% to 40%.  I have gone as high at 95% and as low as 10% and they both worked.  Here is the link to where my spreadsheets are.

flournwater's picture

Nice job with the inter-active spread sheet idea.  I'll book mark the page ...

MommaT's picture


I also frequently substitute my starter for other preferments made with commercial yeast, such as poolishes.   

In these cases, I simply substitute refreshed starter for the poolish, by weight and correcting for hydration.  If the recipe has a huge amount of poolish, I'll do an overnight build-up with my starter to the appropriate amount.



hsmum's picture

Thanks, everyone, for your help. 

We got some horrible news yesterday about a fatal accident involving friends and their child.  Been reeling today from it and news this morning that my 3-year old might require corrective eye surgery.  I'm so tired today but I made a firm starter this afternoon.  The smell of my starter is strangely soothing, as was the wind across the green of the park this afternoon.  I think tomorrow I will find comfort in getting my hands in the dough.


Dragonbones's picture

I'm so sorry to hear about your bad news, Karen!  Here in Taiwan, we're pretty down after seeing non-stop coverage of the death and destruction down south after typhoon Morakot, too. In times like this we do need to find comfort in something--sometimes it's in helping those who are hurt or grieving, and sometimes it's in trying to pursue our normal routine. Kneading dough, baking, and having delicious food straight out of the oven can all be very comforting indeed.