Bubbles, and how dough flows

Post date: Mar 29, 2012 1:31:05 PM

Аlveograph

(this adds a new aspect to our forum, by making a distinction between the bubbles in a dough and the bubbles of the dough. Interestingly, latter helps to understand the former. This distinction is not trivial. For example, in application to the lipid bilayers (membranes) only the bubbles of are considered).

The Chopin alveograph is a tool for flour quality measurement.^[1] It measures the flexibility of the dough produced from the flour, by inflating a bubble in a thin sheet of the dough until it bursts. The resulting values show the strength of the flour, and thus its suitability for different uses. It was developed in 1920 in France by Marcel Chopin, who named it the Extensimeter

http://en.wikipedia.org/wiki/Chopin_alveograph

Here it is:

And here is the sketch of a bubble with its characteristic dimensions

"The first step to interpret the alveograms is to evaluate how the dough sheet is deformed during the bubble inflation".

Launay et al., "Use of a Chopen alveographe as a rheological tool. I. Dough deformation measurements"

Cereal Chem., 54, 1042 -1048, (1977)

From: Launay B and Bur´e J, "Use of the Chopin Alveographe as a rheological tool. II. Dough properties in biaxial extension".

Cereal Chem 54:1154–1158 (1977).

Questions to discuss:

• What are the substantive differences between the party balloons and the soap bubbles?

• Kids: What is Rheology? (we will use this word later)

• What can we learn by using Alveograph?

• To answer this question, we need to understand how the bubble grows.