Calculating bakers percentages with sourdough

Count the flour in the levin, starter, and all other sources as part of the overall flour.

Ford

It depends, for me. I have all my bread formulas in a big spreadsheet. Each kind of bread has a separate table for the levain (or other pre-ferment) and then for the dough itself (which has a line for the levain or pre-ferment). Off to one side I have a little column where I add up all the flour, including the pre-ferment, and all the liquid, and then divide. So I can see in the table for the final dough what the hydration level is without the separate calculation for the pre-ferment, or I can determine the actual hydration level. This way I can tweak either the pre-ferment, the dough, or both to get the hydration level I want. Either way, it doesn't really matter that much as I prefer to go by the feel of the dough, but it is useful when experimenting. For example, if I want to use a firmer starter (for characteristics other than hydration) I can then adjust the final dough formula to keep the overall hydration level the same.

When developing a recipe, what matters to me is the percentages for the final dough. This includes the flour and water in the leaven. It does me no good to picture in my mind's eye a 70% hydration dough, for example, only to have not included the flour and water in the leaven which may then bump up (or down) the total hydration quite considerably. 

So at first, I always calculate a recipe sans starter. Once I have the total amount of ingredients, I then decide how much starter there will be as a portion of the total dough weight. It can be a bit arbitrary, I admit. Typically, I either . . .

1) Base it as a percentage of the total dough weight -- so for an 800 gram loaf I may decide that I want it to be 10% starter by weight, in which case I will use 80g of starter. Or if I want the dough to move faster maybe I'll use 20% starter by total dough weight (160g). Or for slower moving dough I may use 5% total dough weight (40g). 

Or . . . 

2) Base the amount of starter on 25g multiples. So starter might be 25g, or 50g, or 75g, or 100g, or 125g, or 150g, etc. I have no logical reason for using these multiples other than that the numbers are intuitive and pleasing to me. I could just as well use multiples of 10g or 20g or 15g or even 7g or whatever. 

Once I have my final dough percentages, and my starter amount as a portion of the total dough weight, I simply remove the water and flour that's in the leaven from the total ingredient amount. 

So . . . 

If I have an 800g recipe that's been calculated at 60% hydration with 2% salt my total ingredients would be 500g flour, 300g water, 10g salt. (yes, i know that's actually 810g, but I don't sweat the small stuff -- if I scale the recipe for many more loaves then I will adjust for the extra). So if I decide to use 10% starter as a percentage of total dough weight (80g) and my starter is 100% hydration (which means my starter contains 40g water and 40g flour), then I simply subtract the flour and water in the starter from the total ingredients to get my final recipe: 460g flour, 260g water, 10g salt, and 80g starter @ 100% hdyration). If my starter were 50% hydration (approx. 53g flour and 27g water) then my recipe would be: 447g flour, 273g water, 10g salt, 80g starter @ 50% hydration.

I don't like calculating starter in baker's percentage because it leads me down a dark rabbit hole . . . if i want to make an 80% hydration dough, and I decide to use starter in the amount of 20% by baker's percentage, how do I calculate that?

Well, to determine how much starter 20% is by baker's percentage I first need to know how much flour is in the dough. But how can I determine how much flour is in the dough when part of the flour is in the starter? And how can I determine how much flour is in the starter when I can't even determine how much starter is in the dough? 

I don't like this kind of circular thought. I'm sure there are some mathematically inclined folks out there who have an elegant formula for just this sort of thing. But I hate math. It just seems easier to me to know the total ingredients in the loaf and then to portion out the starter afterwards. This way, an 80% hydration dough is always exactly 80% hydration. 

Sometimes, when relaying a particular recipe, I may calculate out the amount of starter and/or pre-fermented flour by baker's percentage after the fact. But that is only for the convenience of others. Those numbers are not how I calculated the recipe in the first place. 

This is what works best for me. It allows me to picture hydration accurately when formulating recipes, and to easily account for my ever changing whims when it comes to the amounts and hydrations of starter that I use. 

Cheers!

Trevor

recipes and I tend to do what Trevor does.  I'm always playing around with my starters so they are printed as 100% hydration but that isn't always the case. I often use a stiffer culture starter and feed it for my purpose.  I usually have starters at different stages of fermentation in the refrigerator and can also pick and choose for spontaneity.  

My flours here in Laos have proven to me that recipe hydration isn't always the same around the world.   The flour is much dryer packaged for preservation in plastic sealed bags.  But the hydration of a recipe can be a guide.  It helps to know the location of a recipe and the Author's concept of the dough "feel."  I find that "feel" more valuable than the printed hydration of a recipe.  Funny too as dough feel changes with time as the dough ferments.  Depending on the flours used, a dough can start out wet and then within half an hour absorb the water and feel dryer.  It can also start out firm and soften.  I have learned to mix up the dough, let the flour swell and hydrate (with or without all the ingredients) for a minimum of 30 minutes before making any adjustments with the liquids in a recipe.  And that includes kneading.  <---(put a star on that tip) 

The first time I run thru a new recipe, my notebook is full of notes along the lines describing the dough, how it mixed, aromas, texture, etc. The second run involves tweaking hydration to come closer to what the recipe should do with my ingredients (this is where experience comes in.)  By the third or forth time, I'm working on how the loaf should look like if there isn't already a preset "shape."   

I calculate the feeding of the starter for a recipe by first deciding when I want the loaf finished and go backwards.   A big part of that is how dominant I want the bacteria to be in the flavour of the finished bread.

That would be the Bread Baker's Guild of America.  Being miserable at anything beyond 4th grade arithmetic I followed this template for building my spreadsheet.  An example is at this comment.  The spreadsheet takes some work to build, but once in place it makes life significantly easier for me.

Even with Trevor's concept of imagining the total ingredients without taking the levain/poolish/biga/you name it amounts into consideration, this works well, as that amount can be zero until the framework of ingredients can be filled in.  And then the amount of levain can be modified as one wishes. 

As it is an image of a spreadsheet, any internal calculations are not portrayed, but the BBGA newsletter which I used to build this is here and has made life with formulae for dough infinitely easier for me.