2.2.3.2. Temperature, density and internal structure. Batter temperature was measured directly using a probe digital thermometer.
Batter densitywas determined in duplicate as the ratio of theweight of a standard container (100 mL) filled with batter to that of the same container filled with water (density, 1 g/cm3).
A drop of batter approximately 2 g in mass was placed on a microscope slide. The samplewas coveredwith another microscope slide, taking care to avoid the capture of air bubbles. Two paperclipswere used to press the slides together, creating a layer of batter of constant thickness between the slides. Batter samples were imaged using a Leica DM750
microscope (Leica Microsystems, Heerbrugg, Switzerland) with 40×magnification. A Leica EC3 camera was mounted on the microscope,providing digitized images using LAS EZ V1.7.0 forWindows (Leica Application Suite) software (LeicaMicrosystems, Heerbrugg, Switzerland).