Hallo! This question seems really random, so I decided to ask here. Basically I was surfing random blogs and read on one that slicing a ganache tart with a hot knife can give vein-like appearances on the side of the ganache due to the Maragoni effect: I was pretty intrigued; the only time I heard of Marangoni effect was the time I did the soap-propelled boat thingy when I was younger and didn't really read about what it actually was. According to wiki sensei, it's an effect brought about by the migration of liquids in a liquid-liquid boundary due to differences in surface tension.
According to the source, the ganache melts when it's cut by a warm knife, and liquified emulsion pulls onto itself due to high surface tension. The veins become finer nearer the bottom of the ganache tart because the knife cools rapidly from slicing and so the effect is reduced. The author then advises to slice ganache/mousse cakes with a very sharp cool knife because the oft recommended heated knife cut will produce these veiny effects.
I tried googling to verify this but couldn't bring up much apart from the fact that the effect is also seen in wine. Coooool but is the ganache thing accurate? I don't really get it, wouldn't the temperature gradient be from the top to the bottom of the slice? I don't really get what 'pulls onto itself' means here and can't really visualise it happening, so if anyone knows about this and can explain this that'd be awesome, thanks!!
