The Fresh Loaf

News & Information for Amateur Bakers and Artisan Bread Enthusiasts

Water Tempreture

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robied's picture
robied

Water Tempreture

Hey guys,

 

I've got a exam on next week for baking, and am a bit stuck on getting the correct water temp for the dough too finish at 27-28degree's celcius, Obviously, depending on how big the dough is, and how big the mixer is your going to have to use different factors, but I've heard about a major factor, and a simple factor? From how I was taught, We get the flour tempreture add it to the room temp, divide that by two and subtract whatever you get from 39dc,

 

Thanks,

 

Rob :)  

sphealey's picture
sphealey

Everything I have read about professional bread dough making says that there should also be a factor to account for the heat that the mixer will add to the dough during the mixing process, which is going to be quite large. I would imagine that these factors could be obtained from the mixer manufacturer but I also get the impression that the notebook with the actual dough temperature rise recorded over time is one of the few things that bakeries will not share with one another.

sPh

robied's picture
robied

I normally mix my doughs at 17degrees, and the 55kg dough comes off at around 27-28.. thats in a big mixer, i think in a little mixer i'd have to have it a touch cooler.. There are factors, major factor and a simple factor.. but i don't know them.. lol

LindyD's picture
LindyD

Hamelman talks about the friction factor in Bread [pp 383-384] as well as a method to establish it for your own mixer.

I contacted KitchenAid after reading Hamelman and asked. They responded:

"This means that 2 minutes of kneading time at Speed 2 on the KitchenAid Stand Mixer is equivalent to 12 minutes of hand mixing.

"Because the kneading time for bread is between 2-5 minutes on Speed 2, the tempurature [sic] of the bread should only rise about one degree per minute."

The indoor temperature of my kitchen has been consistent so I've yet to test the accuracy of their statement by taking the temperature of the dough before and after mixing.

 

Mike Avery's picture
Mike Avery

As usual, KitchenAid is a bit simplistic.  I find with efficient kneading techniques, hand kneading is about as effective as machine kneading.

 

Also, the friction factor depends on a lot of things.  The size of the batch, the mixer, how long the mixer is run, the speed at which the mixer is run, the kind of flour (whole grains heat up faster than refined flours), the size of the bowl and the room temperature. 

 

In the cooler months, a large mixer and a medium sized bowl showed a negative friction factor - the large stainless steel bowl cooled the dough!  So, you measure what your mixer is doing, you keep tracking it, and you use the real world numbers.

 

Mike 

dougal's picture
dougal

The whole business of "friction factor" is a kludge.

 

Its a simplification for the non-scientific that has become dressed up in technicalities and mumbo-jumbo to appear more authoritative than it is.

 

The concept is this. Take the average of the room temperature and the starting temperatures of flour and water (and any preferment being used). Take the simple average of these three (or four) temperatures. Mix the dough. Measure the temperature of the final dough. Then attribute whatever difference there might be between the average starting temperature and the final temperature to "mixer friction" and record the number that must be added to the starting average to get the final temperature.

Then, next time, use that "friction" kludge factor to allow you to estimate a water temperature so as to end up with the final dough temperature specified in your production formula, which in turn will give the process rise time that you want for your commercial operation.

Why is that a kludge of a calculation? Because it --

- doesn't account for the different quantities (just say weights) of preferment, flour, water and mixer bowl & tools. Take a teaspoonful of boiling water (100C or 212F) and add it to a bucket of iced water (0C or 32F) - does it end up at the average 50C or 122F? - of course not, because the quantities of hot and cold are different. But in this friction factor calculation, the starting temperatures are just averaged without accounting for quantities.

- doesn't account for the fact that these materials have different (technical term) "specific heats". (For those that skipped school physics, rather than explain it, I'll just point to http://en.wikipedia.org/wiki/Specific_heat )

- and there are other tiny details like the fact that the act of dissolving the salt sucks up some heat... (this is used in some old ice cream makers)

However, for the same quantity of (broadly similar) dough in the same mixer, mixed at the same speed for roughly the same time, (like in a production environment) then it'll give *some* sort of indication as to what sort of water temperature is going to help you hit your production scheme's ideal temperature for the "correct" rise time.

And I can understand that students of commercial baking would need to understand how to do this simple (and in repeat production likely useful albeit rough) calculation - however I'd also have hoped that they'd be taught that its just a (process-dependent) estimate, rather than scientific truth.

Nevertheless it is a misunderstanding to think that there is some magic number, a property of the mixer, that the mixer manufacturer ought to be able to tell you.

Its a kludge, and in the same mixer, you are going to see different numbers for different recipes/formulae/quantities.

At home, we aren't bothered about controlling the dough temperature so precisely, such that the dough rise time is exactly 2 hours 20 minutes (or whatever) in order that that the wholemeal will be ready to go in just after the baguettes come out of the oven (or whatever)... so we don't need to worry too much about hitting final dough temperatures terribly accurately. Mixer bowl a bit cold this winter morning? Either warm it with some hot water, or use slightly warmer water than usual in the mix. And in hot weather, use cooler water. But then, are you tightly controlling the fermentation and proofing times and temperatures? 

Mike Avery's picture
Mike Avery

Yeah, it's a kludge, but it's a good kludge.

 

It varies from mixer to mixer, from recipe to recipe.  It varies from time of year to time of year (depending on how meticulously the bakery is climate controlled).

 

Like most kludges, all it has going for it is that it works.

 

Like most kludges, it's a hassle becasue you really should track it so you'll know what's happening as the seasons change, as batch sizes change, as mixers change as different recipes are used. 

 

Still, if you know that thie recipe will rise 20F when mixed in that mixer, you know that you need to adjust your water temperature to compensate.  The average artisan baker won't have enough control over his, or her, environment or process to be able to calculate the friction factor based on the specific heat of ingredients.  Yeah, just try calling you miller and asking about the specific heat of your flour.  Across the country you'll hear their laughter - without the phone.

 

Close enough is often close enough. 

Mike

 

Henry's picture
Henry

 Rob Since it’s an exam, you’ll probably be given the friction factor. In real life, you’ll figure out your friction after one or two mixes. You can also take an educated guess the first time keeping in mind the room temperature (eg, cold room equals cold bowl) type of machine, speed of mixing and size of dough Here’s how it works; You say you want a desired dough temperature (DT) of 27 Celsius 

 27 Celsius x 1.8 = 48.6 ...add 32 …gives us 81 Fahrenheit or…

81 Fahrenheit minus 32 = 49... divided by 1.8 = 27 Celcius

 Let’s say you are including a starter... so you multiply DT x 4 because you are working with four factors: starter, room, flour and friction.

Subtract your room temperature, subtract your starter temperature, subtract your flour temperature, subtract your friction factor… this will give you water temperature

If you are not using a starter, the DT is multiplied by 3 because you are working with three factors; room, flour and friction.

Subtract your room temperature, subtract your flour temperature, subtract your friction factor .This will give you water temperature. Most people shy away from the math but it’s really not that invasive. Using a starter? Multiply the temperature you want by four. Not using a starter? Multiply the temperature you want by three. And then start subtracting.

Here's an example using Fahrenheit, straight dough, no starter

DT = 81 ( too warm, unless you’re making a sweet dough) multiply by 3 so 81 times 3 = 243, subtract a room temperature and we'll say it's 75 ( got to buy a room thermometer) so that gives you 168F. Now you subtract your flour temperature, let's call it at 77f so that brings you to  91f. Lastly, subtract your friction and  22 might be a good guess. That leaves you with a water temp of 69f and that’s how you do it

Good Luck H

Henry's picture
Henry

 

Dougal

Arriving at a desired dough temperature is not an exact science for reasons

that you’ve given.

Still, a student should at least understand how to get there.

I was in a class a few years back brushing up on baguettes.

Our instructor asked us to get into groups of three and mix baguette dough with a desired final temperature of 75f.

We were all new to this lab; room, equipment, etc. so it helped to have some sort of guideline as to how to arrive at a desired temperature. Even after calculating, you’re right, there was still an amount of guesswork involved.

We hit 76.5 f.

It has been my experience that most people fresh out of school have no firm grasp of

baker’s percentage or how to arrive at a given dough temperature.

(Many have trouble accurately weighing flour.)

Baking at home is fun ‘cause there’s no production pressure.

In the industry, a mixer starting at 7pm needs to have dough ready to process by, let’s say

9:30, because that’s when the team of shapers arrive. The temperature of final dough is important.

Not good if shapers are standing around with no dough to process.

After a certain amount of time, when one is using the same mixer or favourite bowl with a wooden spoon,  working in the same room, a baker, whether shb or professional will make water temperature adjustments by feel.

“Gee, it’s cool out today, I’ll add warmer water to the dough”

H

dougal's picture
dougal

We are not disagreeing that water temperature adjustment (based on "friction factor" arithmetic) is dramatically more important in the production environment, aiming to produce consistent dough ready at a consistant time, than it is in the home kitchen.

My comments were in reply to the idea of phoning KitchenAid about this matter. (And having them misunderstand the question and reply with a marketing comment about the effectiveness of machine kneading rather than hand kneading - see above.)

Its not really a property of the mixer in isolation from the process, and its not really important for home mixers - like KitchenAids - being used at home.

Maybe its also worth commenting that commercial mixers "work" the dough more intensively, noticeably warming the dough - unlike the typical home mixer.

sphealey's picture
sphealey

I measured the temperature of my weekly rye dough today. 1100 g, 675 flour and 425 water. Starting from ambient of 70 deg.F, approximately 8 minutes in a Hobart KitchenAid KA-5 at a speed of 4. Final temperature at the center of the dough ball, per Thermapen, was 78 deg.F.

I have several recipes that call for 15 minutes at 4-6 in the KA, so I would think the dough could get up to 80-82 deg.F fairly easily.

That's one data point anyway.

sPh

Mike Avery's picture
Mike Avery

dougal commented:

Its not really a property of the mixer in isolation from the process, and its not really important for home mixers - like KitchenAids - being used at home.

 

I have to disagree here.  Some mixers heat dough much more than others.  There are many reasons for that, but some mixers are more gentle than others, so they generate less friction.  Others work the dough intensively, so the generate more friction.  More friction means more heat.

 

While the mixer is only one element in the equation, it is a significant one.

 

Mike

 

dougal's picture
dougal

Mike Avery wrote:
I have to disagree here. Some mixers heat dough much more than others. ...
Agreed absolutely for different designs/models. But not significantly for different examples of the same model.

Nevertheless, because it depends on the quantity of dough (in relation to the thermal mass of the mixer bowl, etc) and the mixer speed setting, (and I'd also say stuff like how much rye, how much 14% protein flour, how much vitamin C, etc there might be in the dough), the "friction factor" is not something that you can reasonably expect a maufacturer to tell you. (Because it depends on what you are doing, as well as the mixer design -- or as I put it above "its not really a property of the mixer in isolation from the process".)

Therefore, if you do ask KitchenAid's customer service people about this, any answer you get ain't likely to be worth a damn. Which was one point I was, seemingly not entirely successfully, trying to explain! The other was that dough temperatures themselves are extremely important for production, but much less so at home - which added to the relatively tiny heating produced by kitchen mixers compared to industrial ones makes the whole subject of "friction factor" (or dough work heating) massively less important at home than in the commercial bakery.

 

Incidentally, I believe the term "friction factor" itself might be a bit misleading.

Doesn't most of the heating come from the deformation of the dough (stretching and relaxing it), rather than friction (resistance to sliding movement)?

Mike Avery's picture
Mike Avery

Personally, I don't believe much that KithcenAid tells me.  They call their mixers "professional" and "commercial,"  but the mixers aren't NSF rated.  Few kitchens would have non-rated gear in their kitchens.  You can do it in some areas, but you have to hassle with the health inspector a lot.

 

Also, they rate their mixers in "flour power" saying a mixer can mix a dough with X cups of flour in it.  Given the variation in cup weights, this starts out being meaningless.  And then there is a difference between different doughs.  A poolish at 100% hydration puts a very different load on a mixer than a bagel dough with the same amount of flour.  It's a joke.  One in poor taste.

 

I agree that KA can't tell you the friction factor because there is so much varation in recipes, recipe sizes and so on.  And to expect them to do so, my antipathy towards them aside, is absurd.

 

As to friction... I think it is a major component.  If you mix a dough with white flour or whole wheat flour, the whole wheat heats up a lot more.  And I think that this indicates the coarser particles are generating more friction and more heat rise.

 

Mike