Boiled potatoes and baker's percentage

I'm working on a recipe I used years ago for a potato bread. This time around, I want to record the recipe and make it easy to adjust the number of loaves. My problem is that I'm not sure what to do with the considerable amount of potatoes that go into the recipe. They have to contribute to the liquid in the recipe, and the flour... Does anyone have an idea how to split the weight of the potatoes?

In the RLB Bread Bible she states potato as 79.8% water and 20.2% starch/fiber in the appendix. She doen't say whether the potato is cooked or not, but in the recipes she boils whole washed unpeeled potatoes, then peels and mashes or rices them. In the baker's formula after the recipes she uses the starch from the potato as part of the 100% flour and the water in the hydration.

I had the same concern when I started tinkering with potato recipes. Instead of boiling them and worrying about the amount of water I may have been adding to the dough I bake mine. Takes a little longer but it's relatively mess free and no worry of xtra water. I choose the strachy kind - they rice beautifully.

I agree with Susie, the potatoes should just be entered in your formula as "boiled/baked potatoes". For a bakers % I divide the total weight of prepared potato by the total weight of the flour used then multiply by 100. Please keep in mind that with the baked potato the prepared ingredient will weigh a little less than the raw.

breadman

After thinking about it a while I don't know how you could really adjust any recipe accurately with something as vague as "potato". Ther are so many different kinds and even amongst like spuds they vary with freshness, storage, etc. The point of boiling with the skin on is they don't absorb a lot of water, but cetainly less than roasting. Boiled would be a blander flavor, baked more robust and earthy. The great thing about boiled is the peeling comes off in one thin layer leaving the nutritious part below the peel, not in the peel like many people think. I'm sure RlB's figures are well researched, they can't be 100% accurate for all potatoes, but it'll get you in the ballpark.

Thanks guys. I'll give 15% a shot tomorrow. I'm not concerned about losing flavor to boiling as this formula calls for using the potato water too.... Nothing is lost.

Peter Reinhart states "Cooked potatoes can be used to tenderize and flavor the dough. Use a ratio of 25% potatoes to flour in the final mix." So if I have 1000 grams of total flour would I add 250 grams of potato's to the initial flour, or would I reduce the initial flour by 250 grams and add the 250 grams of potatoes?