# Food Scientists: Please Explain the Final Dough Temperature (FDT) Formula

This is undoubtedly a question for a food scientist. I have seen online a formula to calculate the water temperature needed to achieve a final/desired dough temperature:

``````water temp = (FDT)*(mult. factor)-(room temp)-(flour temp)-(friction factor)-(preferment temp)
``````

So for a desired dough temp of 78ºF on a straight dough (no preferment, mult. factor = 3) worked by hand (friction factor = 0) with room temperature flour (say 72º), you would need to make your water 90º, i.e.,

``````90 = 78*3 - 72 - 72 - 0
``````

I've practiced this a couple of times now, and it seems to work to within a degree or so...magic! I'm baffled as to why, though. It seems quite suspect that no weights are contained in the formula. And, getting even more scientific, no specific heats.

Can someone please explain where this useful formula comes from? I'm a physicist by trade so this is really fascinating, and I would love to know the derivation. (Math doesn't scare me.) 😂

For reference, here are two of the places that I found this formula:

Thanks!

`FDT = (water temp + room temp + flour temp + preferment temp)/4.`
`water temp = FDT*(mult. factor) - room temp - flour temp - preferment temp.`