How do I convert recipes?

Johnny's picture
I have been wanting to expand my sourdough baking and try different recipes so I finally bought myself a copy of The Handmade Loaf by Dan Lepard 
What a great book and it really makes you want to try new recipes and types of bread from all around the world. One question I do have is how do I convert these recipes to using a sourdough starter? He talks about when you replace the fresh yeast in the recipe with dry active yeast but what proportions do I use to replace fresh yeast with my starter?
Fruit Loaf ExperimentI did try adapting Dan's walnut bread recipe and I just used my normal bread mix with 40% starter and 75% hydration. I decided to make it a fruit and nut loaf so I chose some nice Australian Pecans instead of walnuts and some mini dried figs which had fantastic texture and intense flavour. I soaked the figs in water for 12 hours and used 50g of the pecans to make a paste (50g pecans, 50g water, 2 tbsp honey, 20g melted butter lightly browned, pinch sea salt and I added pinch of cinnamon sugar). The paste is added to the dough for extra layers of flavour. The dough was difficult to work as it got very slack and progressively runny when I was trying to fold it. I think it may have been the extra sugars and extra water in the mix from the rich nut paste. I folded the fruit and nuts in just before trying to form the bread and left it overnight in the fridge for baking in the morning.
I must say this bread turned out better than I expected and the combination of figs and pecans gave the loaf a very nice aromatic  flavour. It was delicious with just a little butter on it's own and I'm sure it will be great toasted...yum!
The crumb was not bad with some irregular holes, although I probably could have baked it longer as I think the water in the fruit meant that it needed longer in the oven. However the bread is nice and moist even if there are some doughy bits on the bottom.
Anyway I am pretty happy with my first fruit loaf but I really would like to know what the general rule of thumb is for converting bread recipes from fresh or dried yeast to using a sourdough starter.
I have just found another great book -The Italian Baker by Carol Field which has lots of authentic traditional recipes but does not say how to convert them to using no commercial yeast at all.
Thanks in advance for any advice and tips for us newbies   :-) Johnny
BTW -thanks for fixing the text editor makes blogging much easier - is that your doing Maedi?


LeadDog's picture
LeadDog 2009 May 25
I'm a little embarrassed that you are quoting me.  I feel I'm a long ways from being an expert.  The 20% to 40 % came from here at  The range does depend on temperate if all you are doing is using the starter to raise the bread.  I'm sure that other factors will come in to play if you want to do something different with your bread.  Check out this bread formula that I converted from yeast .  That has a preferment that is 95% of the flour.  Some of the formulas that I have converted are hard just because I have never thought of how to overcome the problem before.  Post a formula that you want to try and lets see if we can come up with a way to convert it.  Most of the time the first try is just to get the formula close then it can be tweaked.
Johnny's picture
Johnny 2009 June 7
Thanks mate,I'm looking to try one of the recipes from the Italian Baker but have not yet decided which one. They all look so good. I'll post one soon and maybe you can help me out.I'm thinkin maybe Ciabatta ai Funghi..... I think I saw some dried porcini somewhere the other day. :)
Johnny's picture
Johnny 2009 June 6

This is my first experiment converting a recipe using commercial yeast to a sourdough one. I chose a recipe for Mushroom Bread from Carol Field's 'The Italian Baker'. 

The original recipe has 1 1/4 teaspoons of active dry yeast or 1/2 small cake (9g) fresh yeast. 

Ok so the range for converting is 20% to 40% starter to replace the yeast so I decided to go a bit higher in this experiment to a 45% preferment in the final dough. I was not sure of the effect on the dough of all that fresh fungi and I wanted a nice light bread. It is also fairly cool in my kitchen at the moment.

According to the recipe the two secrets of getting the most flavour into the bread are using the soaking water from the porcini and allowing the flavour to develop over long rises. The recipe uses a combination of dried and fresh porcini mushrooms. For the fresh mushrooms I used Swiss Brown mushrooms, because we can't get fresh porcini here in Oz. These mushrooms have a deeper and earthier flavour than white mushrooms, and their firm flesh means Swiss browns hold their shape well when cooked. 

I also found an olive oil with truffles which added just a bit more of that earthy flavour I love.

Added Ingredients:

4 to 6 dried porcini mushrooms

210g Fresh Mushrooms

1 teaspoon minced garlic

You start with soaking 4 to 6 dried porcini in the warm water (447g) for at least 1 hour, drain but save the liquid. You use this mushroom water after straining through cheesecloth 2 or 3 times, to add flavour to each preferment and the final dough. Roughly chop the porcini and pat dry. 

Slice thickly and sauté the fresh mushrooms with the minced garlic and as little of the oil as possible and set aside to cool.

Day 1 evening - 1st Preferment Build                                                                                            

Starter 14g    50%

Flour   27g  100%

Water 19g     70%

Total 1st build  59g                                        

                                                                                                                                                 Day 2 morning - 2nd Preferment Build                                                                                            

Starter 1st build  59g  61%

Flour   97g   100%

Water   68g   70%

Total 2nd Build 225g                                      

                                                                                                                                                 Day 2 evening - mixed up Dough

Dough Formula                                                                                                                                  

Flour 500g 100%

Water 360g 72%

Salt      15g  3%

Preferment 2nd Build 225   45%

Diastatic Malt 10    5g   1% 

(This is Malt blended with Bread Flour at 1g Malt to 10g flour. Diastatic Malt is normally added at 0.1% of flour weight)

Olive Oil (with truffles) 20g  4%

chopped porcini (mixed into dough)

Fresh Mushroom    200g  40% (folded in last)

Total  1328g

I mixed up the dough stirred in the re-hydrated chopped porcini covered the bowl and then put the lot into the fridge overnight. 

Day 3 - morning 

Take out the dough and fold once and return to the fridge.

Day 3 - evening 

Take out the dough let it warm to room temperature.

Folded it once every hour for four hours. 

The sautéed mushrooms were chopped in half and folded in last just before shaping

The dough was patted down into a rough rectangle shape and half the chopped mushrooms scattered on the dough. The dough is then rolled up tucking in the ends and then shaped into a ball and rested 10 minutes. The dough was patted down again and the rest of the mushrooms scattered and rolled up in the dough again tucking in the ends.

Shape into a ball or oval, being careful not to expose the mushrooms. I decided on one large boule and placed it in a cane banneton which I put inside a plastic bag and popped the lot into my microwave to rise. I have found on cold nights the microwave with the door slightly open so the light is on, works quite well as a proofing box and keeps the dough out of drafts.

After an hour or so when the dough had risen I put the banneton back in the fridge for baking in the morning.

The end result:

This experiment certainly worked. The bread was nice and light with delicious moist mushroom bits with a hint of garlic. 

I loved this bread and will certainly make it again :)

LeadDog's picture
LeadDog 2009 June 7
Hey that looks really good.  Now I'll bet you feel better about converting recipes to sourdough.
Johnny's picture
Johnny 2009 June 13
Thanks, it certainly has inspired me to try more. I am finding your spreadsheet handy when working out the formulas.Check out my next post where I was originally looking to convert Dan Lepard's Cherry, fennel and rye loaf but then I found a similar one but I used cranberries which I like and fennel seeds which I love.
Johnny's picture
Johnny 2009 June 13

Semolina Fennel Seed Bread with Cranberries and mixed seeds
My take on converting this very tasty bread based on Susan’s (Wild Yeast recipe). I went for 47% preferment in the final dough because it is so cold in my kitchen at present and I was not sure how well the starter would do. 

I also chose to use a mix of Pepitas, Pine Nuts and Sunflower kernels for my seed mix, mainly because that is what I had in the cupboard.

I mixed up this dough in the morning with the cranberries, fennel and mixed seeds and covered the bowl with a plastic bag and threw it in the fridge till I got home from work that night.  

I pulled the dough out to warm up. I folded it every hour for 4 hours and let it rest on the kitchen bench covered with a plastic bag in-between folds. The loaf was then shaped and let rest in a cane banneton for another hour before being popped back in the fridge overnight, ready for baking in the morning.

Here is the formula I used:

1st Preferment Build                Starter               13g  50.00%Flour                 26g  100.00%Water                14g  55.00%Total 1st build   54g       2nd Preferment Build    Starter 1st build    54g  65.06%Flour                    83g 100.00%Water                   83g 100.00%Total 2nd Build   220g       Dough Formula      Semolina Flour             230g              White unbleached PF    233g              Total Flour    463g 100.00%Water                          245g    53.00%Salt                               11g     2.30%Preferment 2nd Build   218g    47.00%Olive Oil                        22g     4.60%Cranberrys                  110g    23.75%Seed Mix                       70g   14.70% (Pine Nuts, Pepitas and Sunflower) Fennel Seeds                   7g      1.50%Diastatic Malt 10              7g      1.50%(This is Malt blended with Bread Flour at 1g Malt to 10g flour.)
The result:
This bread had that fantastic fennel smell as it was cooking. I love fennel but I was really surprised at how well the sweet cranberries went with the fennel and nice crunch from the pine nuts and other seeds. I sprinkled the top with a little polenta before baking and found it gave the crust an extra little crunch that added even more to this bread. 
I am so glad I have tried converting recipes, it has taken my bread to a whole new level of taste and textures. So I certainly will be making this one again....another great bread added to the repertoire! 
cheers, johnny
LeadDog's picture
LeadDog 2009 June 14
Looks great.  I love cranberries in my breads too.  One of my favorites is walnut cranberry bread.
TeckPoh's picture
TeckPoh 2009 June 14
Great ideas, guys. Johnny, I really appreciate you sharing your bread adventures with us. Thanks!
Millciti's picture
Millciti 2009 June 15

You have come so far so fast... Thanks for sharing!  I love a good pane dolce.  I would be guessing that this is also inspired by the italian baker in you.   It certainly looks delicious.  I think this one might be next on my list to try.  Just curious what do they normally use for the seeds? 



Johnny's picture
Johnny 2009 June 16
The original recipe just had the fennel seeds but Susan added pine nuts out of necessity when she did not have enough currants.
LeadDog's picture
LeadDog 2009 June 22
I made another spreadsheet that is helpful for me to put formulas into bakers percentages.  This spreadsheet is for when you make a bread from a volume recipe and you weigh the ingredients as you make the bread.  If the bread is any good you can just enter the weights that you used and the spreadsheet will calculate the bakers percentages for you.

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