Tuesday, February 21, 2012

Variables when Frothing Milk

Clean and tasty milk as most people know it
I have been enlightened about a scientific article posted today at two o´clock, regarding factors when frothing milk, which wasn't something that I had known before and therefore is extremely relevant for the coffee society in my opinion. I will briefly cover the scientific article and reproduce the statements that I find interesting.

The basis of this article was set in a Copenhagen coffee bar, where a customer received a flat foamed cappuccino and therefore complained to the baristas. Their explanation of why the frothed milk was flat, where cause it was ecologically produced and cause the cows was fed with straw instead of grass.

Commenly known knowledge among people with their own espresso machine and baristas are that frothed milk are produced by steam pressed into the milk and thereby incorporating tiny air bubbles. The article states that these air bubbles is encapsulated by thin shells of protein and between these air bubbles runs tiny channels. The fat from the milk gets stuck in the channels and contributes a non-collapsing foam layer.

A more scientific explanation of this non-collapsing foam layer, is in the world of physics known as tension of the surface or surface tension. The foam layer consist of protein molecules which attracts each other and thereby creates a cohesive, which is tension of the surface. In other words is the protein molecules keeping each other in line, which keeps the foam layer intact. 

First hand the baristas at the Copenhagen coffee bar seems a little off by their judging of the cows intake of nutrition should have an effect of their frothing skills, but! Actually does the milk fat has a significant matter in the consistency of the frothed milk and therefore does the cows intake of nutrition determine the composition of the milk fat. It could therefore be a pros if the cows had grass on the menu, cause it makes the milk fat more softer.

Above there is determined that the milk fat has a huge influence on the reaction off the frothed milk and therefore is the purchase of either ecological milk or not a significant matter. The ecological milk has not been homogenized and therefore is the milk containing naturally big fat droplets. On the other hand has the non-ecological milk been homogenized, which means that the naturally big fat droplets has become smaller and will contribute to a more consistent foam layer.

The question of wether the milk is ecological or not, is more a matter of the fat droplets and thereby the consistency of the foam. Regarding the situation with the Copenhagen coffee bar, could the solution to the problem also be a pitcher with a little soap left in it, cause this will eliminate the tension of the surface.

Looking forward to tomorrow, cause a Rocket Evoluzione Giotto will drop by the Coffee Channel office for a review in the following week.

// Hendrup

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