The Fresh Loaf

News & Information for Amateur Bakers and Artisan Bread Enthusiasts

Converting recipes Biga Pooish or other

chance's picture

Converting recipes Biga Pooish or other

Hi Folks,

 First thanks for the great site.  I knew nothing about bread making before I came here.  I still know nothing but I make bread each week that my family raves about.  :)

 I have a basic recipe that I use - but I would like to start experimenting with pre-ferments.  I don't really want a different recipe, I just want to modify the one I am using and see how changes in how I make it impact the quality/nature of the bread produced

 So are there any rules of thumb for converting a recipe with no preferment to one that has one? Ratios or proportions of the original recipe ingredients needed to create the Biga, Poolish, or whatever?


Any direction would be greatly appreciated.

proth5's picture

This is the approach that I have been taught.  I am sure there are other ones, but this has worked out for me.

If you are adapting a recipe for a pre-ferment, you first want to determine the amount of flour that will be pre-fermented.  In wheat doughs I have seen this vary from 12% to as high as 33% (although others will tell you that they do much more or much less and they are right - for them).  This weight is removed from the total amount of flour in the formula. 

So, if your original formula calls for 100 grams of flour and you want to pre-ferment 25% - 100 X.25 = 25 grams.  25 grams of flour goes into the pre-ferment and 100-25 = 75 , 75 grams will be added for the final dough

Then one must decide on the hydration of the pre-ferment.  Generally we see pre-ferment hydrations varying from 50 to 100%  This would mean that the amount of liquid (by weight) based on the amount of flour (from above) would be removed from the original recipe to be used in the pre-ferment.  

So, continuing our example, if the orginal recipe called for 68 gms of water and we wanted a hydration of the pre-ferment of 100%, the weight of the water in the preferment would be 25 gms (the weight of the flour)  X 1 = 25 gms of water would go in the preferment and 68-25 = 43gms would go in the final dough.

Then, depending on the length of time the pre-ferment is to ripen, yeast is added.  The following percentages (according to the weight of the flour) are for fresh yeast:

Up to 8 hours    .7-1%

Up to 12 hours   .3-.6%

Up to 16 hours   .1-.25%

Divide by your favorite number to calculate the amount of dried yeast to use (I use 3) - or in the case of most home bakers, since the quantity will be very small if instant yeast is used - use a "smidge" (this is a technical term...).  This is deducted from the total weight of yeast in the final dough.

This is for what is popularly called a poolish or a biga - not a pate fermentee which is a bit different.

According to "my teacher" salt is never, ever added to a poolish made with commercial yeast.  Since "my teacher" will hunt me down if I dare to contradict, I will agree.  But I have heard of other (pretty reputable) bakers who do add a small amount of salt into their pre-ferments - presumably to slow down the action of the yeast.

If you are familiar with baker's percents this can all go into a spreadsheet so that you can make adjustments easily.  If not, I think that this can still get you started - although it is best to start with a formula that is weight (not volume) based.

Hope this helps.

Happy Baking!

Soundman's picture

Excellent post, proth5!

Just for the record, the amount of pre-fermented flour I have seen in a book (i.e. by a professional baker) goes up to 50% in Hamelman's Bread. Since hansjoakim brought the reference up, I thought it was worth mentioning. If I recall correctly, 2 formulas ("Rustic Bread" is one of them) in the chapter on Preferments use that much prefermented flour.

It doesn't change the fact that your post was very clear, very helpful, and spot on!

Soundman (David)

hansjoakim's picture

First off, proth5 nailed it in the above post! If you're down with baker's % and follow the directions given above, you'll be well on your way to tweaking straight recipes into recipes that use preferments. I would also suggest to have a look at the chapter about prefermented breads in Hamelman's "Bread". Have a look here:

That's a great resource as well. Read over the basics in the introduction, and then study some of the recipes in detail. If you find a recipe that is similar to your favourite straight dough, see what amount of flour and yeast that's put into the preferment. Feel free to try different preferments in your adaptions!

The most valuable tool in adopting and tweaking recipes for me, is probably my spreadsheet. Especially if I'm switching between different preferments with varying hydration levels.

Hans Joakim

arzajac's picture

I don't know if this is by the book but I have had great results by adding all the ingredients except for 1/3 of the flour and letting that preferment overnight (or longer) and adding the rest of the flour before I want to do the final bulk fermentation.  I do cut down the amount of yeast.  I have never had a problem such as insufficient yeast activity and have great flavour and keeping.

It's really simple.  You can't make a mistake.  I always add the salt to my preferment since I tend to forget it otherwise.

chance's picture

Thanks everyone, that is even more information than I was hoping for!  I'm putting together a spreadsheet and then on to experimenting.


blaza192's picture

Found this old thread wondering the same question. Yeast is used twice though, right? One for the preferment and one for the final dough. How would I calculate how much yeast is needed for the final dough? Would it be based on the original recipe?

BetsyMePoocho's picture


I'm probably going to get 'shot-down', but this is a typical preferment for all my types of dough:

33% of total flour in grams, 100% water, and 1/2 of a 1/8th teaspoon of Instant or ADY. (tiny pinch)

The mixture will ferment for 16 to 18 hours in a small apartment sized fridge that is maintained around 68f for the time.

I should add for context that all my doughs are about 1,000g of total flour.  I don't make large amounts of dough and this method has serviced me for a long time.

For the 'Final Dough' I use the amount of yeast called for in the recipe or depending on ambient house temp's adjust the amount for a slower first rise time.

Remember,,, it is absolutly amazing what just a 'pinch' of dry yeast and time will do……..

Oh, preferments really changed the flavor of all my breads.

Experiment with preferments….. It is fun…….


blaza192's picture

Thanks Betsy, 

They didn't specify how much yeast for the final dough, so I guess using the same amount of yeast called for in the recipe would make sense. The amount of flour would be the same and most of the yeast in the pre-ferment would be exhausted I think. 

BetsyMePoocho's picture


You got it.  Just be sure to remember to subtract the percent of flour and water used in your preferment from the total recipe.  Just like proth5 so well put in his post at the top of this string.

Have fun.


blaza192's picture

I will. Thanks Betsy!

blaza192's picture

Ha. Just reread it and it said to deduct yeast from final dough. For small recipes, amount is so small though that it's negligible.