Hello Doctor,

I have been testing dough formulation with my bakers percentages but am a bit confused regarding the preferment. I typically prepare 90 grams of biga using 1/3 of an 1/8 tsp of IDY. My biga is about 20% total of my flour weight. If I was to prepare this preferment in bulk for my restaurant, how much IDY would I need to put in the preferment?

Basically i’m looking to do this:

25 pounds of flour

5 pounds of flour for perferment (20% starter)

Is it typical of a pizzeria to use 20% preferement?

Thank you

Brooklyn;

If you are going to use a fixed amount of biga in each dough (20%) the easiest way to manage the biga with regard to size is to base the IDY level on the amount of flour in the biga. To do this you need to do the following:

- Weigh the flour in your biga.
- Weigh the amount of IDY added.
- Confirm by bake test that this amount of IDY is indeed what you want to use.
- Divide the weight of IDY by the weight of the flour in the biga and multiply by 100 to find the percent (bakers %) flour in the biga.
- Decide how much flour you want to use in the master biga.
- Using your calculator, enter the amount/weight of flour to be used in the master biga, then press “X” and enter the IDY percent you got in #4 above. Press the “%” key and read the amount of IDY to add to your master biga. Remember, the amount of IDY will be shown in the same weight measures as you showed the flour weight in (pounds, ounces, grams, kilograms)
- Repeat the above to find the amount of water to add to your master biga.

Remember that when managing your master biga consistency is the name of the game.

Tom Lehmann/The Dough Doctor

Wow okay I’m trying to follow but you lost me a bit. Would you be kind enough to run through an examples with numbers? I don’t know what my IDY weight is for my 90gram biga. I just know it was 1/3 of an 1/8 tsp. Now that I’m scaling to 25 pounds of flour and using 5 pounds flour for biga. What should my IDY be used for the biga?

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Not a problem, first you will need to buy a good electronic scale (spring scales will not work in this application). You can buy them on the internet for $35.00 or less. Make sure the one you get will measure in both grams and pounds/ounces. Place a small container on the scale platform and zero it. Portion your IDY five times placing each portion into the container. Get a total weight of the five yeast portions, in your case use grams for the total weight, now divide this total by five to get the average weight of a single portion. The answer will be in grams. Example: You have portioned the IDY five times into the container and it weighs 25-grams. Divide this by five and the weight of a single portion is 5-grams. Now, portion out the flour used in a single biga five times and get a total weight on the five flour portions, divide this by five to find the average weight of a single flour portion. Example: you portioned the flour five times and the total weight of the five flour portions was 550-grams. Divide 550 by 5 to get the average weight of a single flour portion in the biga, in this case it would be 110-grams.Divide the average yeast weight by the average flour portion weight and multiply by 100 to find the percent (bakers %) of the yeast. Example: 5 divided by 110 = 0.0454546 X 100 = 4.54545 (call it 4.5%). Repeat this for the water so you have the amount of water added to the biga in bakers %. Now all you need to do is to decide how much flour you want to use in your master biga. Let’s say you want to use 20-pounds of flour in your master biga. Enter the flour weight in your calculator, then press “X” and enter the percent for the yeast followed by the “%” key. The number in the display window is the amount of yeast/IDY needed to make a master biga based on 20-pounds of flour weight. Repeat this for the water to find the amount of water to add to your master biga. When you prepare your dough use the biga at 20% of the total flour weight that you have scaled for your dough. Remember to adjust the total dough absorption to take into account the water in the biga.

Tom Lehmann/The Dough Doctor

Thank you so much for the explanation Doc! Can you just clarify the last part about adjusting the total dough absorption ? I use a 61% hydration rate for my regular batch of dough. I use about 41% hydration for the biga starter.

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To clarify, 61% absorption based on the flour in the “dough” not including that which is in the biga? 41% absorption based only on the amount of flour in the biga? Is this correct?

Tom Lehmann/The Dough Doctor

Yes I believe so. So I make a 41% percent hydration in the biga. Let it sit for 18 hours. Next day I start my main dough. Put in 100% of flour and 61% water. Also added salt, and sugar. Let it mix a little. Then I throw in the biga and continue to mix. Last ten minutes throw in the olive oil.

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Does this sound right to you doc? Do my hydration % get messed up at all?

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With 61% absorption based on the total weight of the dough flour plus 20% biga that might be a very high absorption dough. Remember, the total amount of water in that 20% of biga contributes to the total dough absorption. If you give me the formula for a biga for one dough (weight of ingredients) and the flour weight in the dough plus the amount of water that you are adding to the dough I can calculate your total dough absorption.

Tom Lehmann/the Dough Doctor

Tom I sent you a message.

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