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Explanation of DDT formula

Ittayd's picture
Ittayd

Explanation of DDT formula

So the DDT formula to get water temperature is (without starter) is (working in celsius) 24*3-<room temp>-<flour temp>-<friction temp>. E.g. 24*3- 20 - 20 - 10 = 22

I can't make sense of it and would like to understand the intuition. Even glancing at the result, if I add water at 22c to flour at 20c and knead which increases temperature by 10, then the dough will be more like 30c, not 24c. If I want a more accurate formula, it seems to be ((24 - <friction temp>) * (hydration + 1) - <flour temp>)/hydration (so for example ((24 - 10) * 1.65 - 20)/0.65 = 5. Or, in reverse, if I add to 1kg of flour at 20c, 650g of water at 5c, the result is a 14c dough which when kneaded warms up to 24c. 

So again, grateful of any intuition

 

breadforfun's picture
breadforfun

This calculation is only used to get you in the ballpark of temperature, especially for the home baker. It is not a scientific formula by any means, because it leaves out so many of the variables. Even bakeries have proofing chambers so that they can adjust the dough temperature. 

That said, your reference to 10*C as a friction temperature seems awfully high to me. Most references for home bakers that I have seen say to ignore the friction temperature for hand kneading and use 1-3*F for home machines. That is an order of magnitude less than your reference. Again there are many variables including the type of flour, amount of dough, hydration, kind of mixing system, etc. that all affect the friction temperature and a professional bakery would probably work out a different number for each formula.  I have made batches up to 3 kg by hand and found that I could ignore it and still get pretty close. Even the few doughs I mix by machine don’t see a massive increase in temperature after mixing. 

-Brad

gavinc's picture
gavinc

Yes. I agree with what Brad said. Determining the DDT is not exactly scientific, but will get you near the target. I hand mix now (home baker) but previously used a Thermomix on interval function when making a single loaf, but the friction factor was 14C as the action of the mixer was very aggressive. I stopped using it a couple of years ago as I found the hand stretch and folds respected the dough and produced a much better result. The hand mix friction factor is 0 no matter what amount of dough I am mixing.

Cheers,

Gavin 

mariana's picture
mariana

This formula works for open space low speed mixing, because of the room temperature. Even if friction heats the dough little by little, low room temperature and cold kneading surface temperature continuously bring the dough temp down. In the end you will have your 24C dough. If not, then your friction factor is higher than that which you inputed into formula.

High speed kneading in enclosed and warm space, as in bread machine, in thermomix or in food processor, or even inside mixer capable of high speed mixing is a bit different. There I use ice cold water or ice without exception and often have to chill the dough right after kneading down to DDT before in begins fermenting.

High friction factor is rather commonplace according to this baker: 

https://www.busbysbakery.com/desired-dough-temperature/

Gareth says that it depends on time and on the chosen kneading method, i.e. on kneading intensity

Friction Factor for dough mixers:

Light incorporation: 0C (32F)

Standard mix (8 mins): 4C(40F)

Long mix (14 mins): 7C (44F).

Friction Factor when hand kneading:

My research has indicated that:

Light incorporation: 1C (32F)

Standard mix (10 mins): 7C(40F)

Long mix (20 mins): 14C (44F)

But it depends heavily on how you knead your dough!