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Permalink Reply by jonathan bonchak on January 5, 2011 at 6:01pm

The Professional Barista's Handbook!

 - http://www.professionalbaristashandbook.com/

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Permalink Reply by Phil Proteau on January 6, 2011 at 4:19am

Culinary student text books are really good for this stuff.  I got one at a used book story or yard sale or something.  You could try a student book store if you have the money for it.  They really get into the chemistry and physical science in a much more academic way than you usually see any training materials for coffee.  Or to to culinary school as a student, couldn't hurt.

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Permalink Reply by Brady on January 6, 2011 at 5:19am

I suspect that Harold McGee's "On Food and Cooking" would cover this well, but I lent my copy out!

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Permalink Reply by Bryan Wray on January 6, 2011 at 8:03am

I'm particularly interested in how elevation affects the scald temperature of milk and whether or not it is more or less linear to how water is affected by elevation.

 

Something to think about as we plan for regional competitions.

 

-bry

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Permalink Reply by Phil Proteau on January 6, 2011 at 9:21am

The the components of milk, sugar molecules, protein chains, milk fat, undergo changes as they take on heat energy.  Protein chains "unravel", sugar molecules fall apart, fat melts.  These changes happen only when energy reaches it's tipping point.

 

Water boils as a result of the pressure, or lack there of, that surrounds it.  Lower elevations have higher air pressure, "holing down" the water vapor and requiring higher temperatures before the vapor can escape into the atmosphere.  That is why water in steam boiler can be above the boiling temperature without boiling.

I don't think, therefore, that the elevation will have an effect on the milk texture, sweetness, and flavor, at different elevations the way water can boil with lower temperatures at higher elevations.

 

And for the original post- what does it mean to you to scald milk?  I find that many different people have many different ideas about what that means.  For my own purposes, I define the scalding of milk as this:  the complex sugar molecules have broken down to simple sugars, which have subsequently broken down to smaller molecules which are no longer sugar, and the proteins have changed radically enough to take on more savory flavors, resulting in a loss of both sweetness and pleasing flavors. 

 

 

Bryan Wray said:

I'm particularly interested in how elevation affects the scald temperature of milk and whether or not it is more or less linear to how water is affected by elevation.

 

Something to think about as we plan for regional competitions.

 

-bry

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Permalink Reply by Joona Suominen on January 6, 2011 at 9:42am

International Dairy journal has released god knows how many articles on the subject but I have one on my computer which I could upload if you people want to read it. 

 

Foaming properties of milk: a review of infulence of composition and processing. (Huppertz, 2010) 

 

The References had a few articles which might be interesting too but I haven't had the time/interest to dig them out yet. 

 

Obviously scalding is bad because it breaks down the whey proteins in milk which ends up in burnt/porridge-like taste. I'm quite certain that fat content doesn't change the temperature where the proteins start to break but the fat does seem to store quite a lot of energy before the milk starts to heat. 

 

As for the elevation, I have no idea. The changes in water's boiling point are related to pressue. I can't see how pressure and the breaking of proteins would relate. Not saying that they don't though.

 

Common sense says that human's body temperature should still be 37 degrees Celsius no matter how high they climb (where the boiling point might be less). Fever and Milk scalding both relate to proteins denaturing or breaking so I think the milk temperature should not be affected by the elevation. Yet again, it might be completely wrong.  

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