The Fresh Loaf

News & Information for Amateur Bakers and Artisan Bread Enthusiasts

Mixing and RPM's

scardanelli's picture
scardanelli

Mixing and RPM's

I've been reading Michel Suas' book Advanced Bread and Pastry and in it, he writes about the number of rpm's in the mixer that are needed to develop dough to a certain stage.  For optimal development, or what some call the improved mix,  Suas writes that a dough must get 1000 rpm's in 2nd speed.  This is just a baseline number, as many things can effect the amount of mixing time needed (type of flour, amt of dough being mixed, etc.).  I was curious as to what the rpm's for various speeds were for my 5qt kitchenaid artisan mixer.  I just heard back from kitchenaid, here's what they said:


The planetary RPM's for the 5-qt. tilt-head Artisan Stand Mixer are as follows:


Stir speed - 60
Speed 2 - 95
Speed 4 - 135
Speed 6 - 180
Speed 8 - 225
Speed 10 - 280


...so that means that after 4-5 minutes on stir speed for incorporation, it will take roughly 10 1/2 minutes on 2nd speed (1000/95) for an improved mix. 


I haven't tested it out yet, but I thought others might be interested.  I think the overall feel and look of the dough is more important, but it's nice to have a general idea of how long it should take.  Let me know what you think:)

nbicomputers's picture
nbicomputers

do you mean rotations or rotations per minute RPM


at 1000 rpm so much heat would be created you would burn the heck out of a dough and distroy the gluten

scardanelli's picture
scardanelli

Sorry...yeah, the rpm's would be 95 at second spped and you would mix until you would reach 1000 revolutions, which would be 10 1/2 mins.

davidm's picture
davidm

I think Hamelman mentions 1000 revolutions being a baseline for dough development too, but I'm not sure if he's talking about stand (planetary) style mixers or commercial spiral mixers.


I use a KA mixer with a spiral type hook, and 10 1/2 minutes seems long to me.


I seem to be narrowing in on about 3 to 5 minutes on speed 2. (My manual says that is the only speed to use for the hook, otherwise you can fry the motor) That's with an autolyse though, and for hydrations in the 65 to 70 percent range, and with seeded breads containing a portion of whole grain flours. This is more or less in line with the suggestions in BBA, I think.


I've been folding, usually once sometimes twice, during the primary fermentation also. Still trying to hone my sensitivity to the needs of the dough however, so we'll see where it all ends up.


Just checked my mixer, and noticed that the actual hook rotates roughly three times for every single rotation of the powerhead, if you see what I mean. So which is it, I wonder?

gaaarp's picture
gaaarp

I, too, thought 10 1/2 minutes of kneading with the KA seemed like a lot.  It also struck me that 4-5 minutes of mixing was more than I normally do.  I have taken to mixing with my dough whisk and either kneading by hand or relying on stretch-and-folds for my kneading, but when I was using the mixer a lot more, I generally mixed for no more than 2-3 minutes and kneaded for about 5 minutes.  Occassionally, I would knead for 3-4, rest the dough for 5, and then knead another 3-4.  But I don't know that I ever approached 10+ minutes of kneading.

gbguy71's picture
gbguy71

FWIW - I too had questions about KA's speeds.  This is for a Professional 600 (other models can have different speeds).  According to KA, for speed 2 the "Planetary RPMs" are 95 and the "Dough Hook RPMs" are 347.

This same ratio, planetary speed * 347/95 (or 3.65), should work for determining other "beater rpms".

I actually had a hard time figuring out Handelman's table until it dawned on me that he was talking about total combined time at speeds 1 and 2 to reach 900 to 1,000 revolutions.  I'm still not sure how he determines when to switch from speed 1 to speed 2, as you can reach the desired revolutions any number of ways.  Though for a KA, if you go by the book, you should just stay in speed 2.

 

scardanelli's picture
scardanelli

My process is pretty similar.  I usually autolyse for 45 min, then 5 min on 1st speed and 3 min on 2nd speed.  Then I fold 2-4 times during bulk fermentation. 


Maybe the 1000 revolutions is for doughs that don't use an autolyse or stretch and fold.  Honesty, I would worry about the motor on my KA if I let it go 10.5 mins straight.  Maybe 5 mins, then a 5 min rest, then 5 more mins. 


Suas gives average rpm for spiral mixers, but says that you must check with the manufacturer for stand (planetary) mixers because they can vary so much.  It seems like the actual rotations of the hook itself and the rotations around the bowl would both be factored in together to come up with the total rpm's, but that's just a guess.  I'm not sure.  I'll have to do some experimenting tonight.

nbicomputers's picture
nbicomputers

it depends on what your mixing rye  or other sour doughs should be mixed less to avoid tearing of the gluten.  but other doughs like kiser and  hard crusted bread made with hy glutem flour do take 10 minutes or more.  some sweet doughs like bun dough and coffee cake and babka could take 15 to 20 minutes to reach the clean up stage (the dough pulls away from the mixing bowl) and a few minutes after that to reach max development.


also dough temp as well as the mixing method (hook or padel) has a factor as to when the dough will be done.


the best thing is to know the feel of the dough and judge by touch rather than time.  the best chef 's rule is " its done when it's done"

LindyD's picture
LindyD

I had been trying for a year to get a response from KA about the friction factor numbers at speeds one and two for the KA Artisan.  Needed the information for computing dough temperature.  They were completely clueless.  Congratulations on even getting a response!


After spending an hour or so digging deep into their "conversations" forum some months ago, I found one post claiming 196 at speed one and 311 at speed two.


If the 60 rpm at speed one applies only to the planetary (where the hook is inserted), the 196 could be a reasonable number since the hook spins much faster beneath the planetary.


One of these days I'll follow his [Hamelman's] advice and make a trial dough to calculate the number for my mixer.  


Thanks for posting those numbers.

fthec's picture
fthec

The information I received from KA regarding my Epicurean 6 qt mixer is as follows:


stir--  40 rpm


#2--  54 rpm


#3--  79 rpm


#4--  104 rpm


I routinely mix on #2 for 3 minutes until the dough comes together and then switch to #4 for 6-7 minutes.  At this point, the dough has some good strength but still requires an additional fold or two during BF.  I will try an experiment soon where i increase mixing time to 8-9 minutes without additional folds to determine effect on dough development/ flavor etc.  I just have to be very cognisant of the dough temperature--  water needs to be 45-55F.  While i'm at it, i'll try a third batch developed by hand only (using Bertinet method of folding).  Should be interesting.


Franc

scardanelli's picture
scardanelli

ok... so I just mixed up a batch of Hamelman's country bread. 


I didn't use any autolyse, I mixed for 5 mins on 1st speed for incorporation and 10 1/2 minutes on 2nd speed.


The dough seemed pretty similar in feel and development to my normal routine when I  autolyse for 45 mins, then mix on 1st speed for 5 mins then 2nd speed for 3 mins.


Normally I would fold 4 times, once every 30 minutes.  This time, i'm only going to fold twice, as hamelman calls for in the recipe.


So far, it seems that the extra mixing time to reach 1,000 revolutions is making up for the lack of autolyse and extra folds... we'll see.

hansjoakim's picture
hansjoakim

Another thing to factor in, if I recall correctly, is that if you're using what Suas calls an "Improved mix", there's tops 1 fold involved during the bulk fermentation. I think this is listed in one of the tables following his descriptions of the three mixing methods. I think Suas' book is particularly good on this point, namely how different mixing techniques affect the optimal length of bulk fermentation, amount of yeast that should be included in the recipe, number of folds etc.


Take his "short mix" for instance. To get the desired level of gluten development, you have to fold the dough three or four times. Thus, you need a long bulk fermentation. To get a long bulk fermentation, you must use a low amount of yeast in the recipe.


In most cases, Hamelman follows what I would classify as a "short mix". This is the ideal technique for artisan breads with good keeping qualities and rich flavor (due to low levels of yeast and long fermentation). If you look at Hamelman's mixing directions, more often than not, they're pretty similar to Suas' "short mix" method.

davidm's picture
davidm

I became curious about my mixer speed while reading all this. I have the KA 600 series bowl-lift model


Using a handy-dandy stopwatch, I observe the powerhead rotation on speed #2 to be a fraction less than 60 rpm. The manual emphasizes that speed #2 is the only safe speed for the doughhook.


To go for 1000 revolutions would then be almost 17 minutes!!! Too much.


However the hook itself is rotating roughly three times as fast as the powerhead, so using hook rotations we get about 5 i/2 minutes, which is more realistic in my view.


Another observation: I have a cast metal spiral type hook. With doughs in the 65% - 68% or so hydration range, after about five minutes the dough begins rapidly to climb up  the hook and kinda "ball-up" there, increasingly losing any real contact with the bowl sides. At this point there is virtually no kneading action anyway, the dough has plenty of "muscle", and there is little point in continuing. I don't usually let it go quite this long, but that's what happens if I do.


Wet doughs behave differently of course.

gbguy71's picture
gbguy71

According to KA, and some other posts I've read, for a Professional 600 speed 2 is 95 rpms (Stir is 60 rpms).  Also, at speed 2 the dough hook's rpms are 347.  As Handelman indicates all RPMs are not the same and that a plantary mixer is not very efficient at making bread.  So the KA rpms are a starting point and then your artistry (which I don't have) takes over.

scardanelli's picture
scardanelli

Well, I wasn't able to follow through with my experiment yesterday.  I went out to run a few errands which ended up taking longer than I had planned.  The dough over-proofed by about an hour and collapsed when loading it onto the peel.


At the end of bulk fermentation, the dough was fairly similar in development to what I normally see.  The only thing out of the ordinary for me was the overall experience of baking the bread.  The excess time in the mixer meant that the dough had less "hand time" and the process felt more mechanical and exacting.  I can't say that this made any empirical difference in the dough, but sometimes it's the intangibles that make good bread. 


On another note, I too counted the number of revolutions per minute of my bulkhead while the dough was mixing in second speed.  I don't remember the exact number, but it was in the 60's.  This is, of course, different than the number given by kitchenaid.  I'm puzzled as to how they came up with the 95 rpm's for second speed.  I'm sure that the individual revolutions of the dough hook factor in somehow, but i'm not sure how...