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# Friction generates heat

Whether you use a mixer to knead your dough, or do it by hand, you are using friction to get the necessary action. Friction generates heat (more friction means more heat), and this heat is partially transferred into the dough. How much the temperature of the dough rises as a result of the mixing and kneading process is a function of several factors:

• Mass of the dough: More mass takes more friction to raise the temperature by one degree
• Kneading process: Electric (stand) mixers are generally a lot more intense than kneading by hand. Consequently they heat things up more. Different models and brands have different effects, as does the mixing speed.
• Kneading time: On average the amount of friction produced per second is constant throughout the process, but longer kneading means more overall friction, and thus more heat transferred.

The total temperature increase for a dough as it completes the mixing and kneading process is called the mixer friction factor.

## What is my mixer's friction factor?

Based on the above, you should be able to understand that there is no such thing. It depends on the amount and type of dough that you are making, how fast you spin the dough hook, and for how long. The only thing you can do is use a probe thermometer just before, and just after kneading and note the difference. This will be your mixer's friction factor, for that recipe, that preparation, and that amount. You have to determine this experimentally.

A guideline seems to be, however, that a typical KitchenAid stand mixer has a friction factor in the neighborhood of 40 in most applications. Industrial type/size Hobart mixers are probably more in the 20 range.

## My dough is getting too hot. What should I do?

One fact stand above all: Your dough isn't ready until it is appropriately developed. So, you can't stop kneading completely. What you can do is stop for a while, let the dough cool, and then continue. You may even attempt to cool the dough faster in the refrigerator. This works best for small doughs as they tend to loose heat faster, but can only safe you if you need just a few degrees off.

Secondly, remember that the desired dough temperature is just that: A desire. If the dough ends up a few degrees higher, just take note for next time, and move on.

Next time, reduce the temperature of the liquids you use by the same amount of degrees Fahrenheit is your dough got too hot. This is assuming all other ingredients have the same temperature each time. Increase your noted mixer friction factor by the same amount so that the worksheet can more accurately tell you what temperature your liquids should be.