I have seen 'surface tension' mentioned a great deal, on this and other forums and websites, in relation to the shaping of dough to produce a taut 'skin'. Achieving good surface tension is said to help a loaf keep its shape (especially important when using very soft doughs) and improve oven spring.
I feel rather wary of this idea. 'Surface tension' is a term well-known in physics, and decribes an inherent molecular property of liquids. Water forms droplets, for example, because of surface tension. The surface tension of water can be altered chemically - for example, the addition of a little washing-up liquid will reduce surface tension and lessen the tendency of water to form droplets on a smooth surface. But you cannot mechanically change this property - in other words, there is no physical action you can perform that would change the surface tension of water.
I'm not a physicist or food scientist, but my assumption, given the above, is that when bakers talk about surface tension, they are not referring to the scientific phenomenon. Dough does possess this quality, but I can't see how manipulating the dough would alter it. Stanley Cauvain, in his book Bread making: improving quality, does mention surface tension, but observes only that it can be altered by adding emulisifiers (which would be anathema to an artisan baker). He doesn't mention the possibility that surface tension can be altered by shaping. He also notes that surface tension has little impact on dough rheology (that is, it's ability or tendency to flow). In other words, altering the surface tension (the molecular property) of the dough would have little impact on whether a soft dough would spread out on a flat surface.
I guess, then, that when other bakers talk about achieving surface tension in their dough, they are referring less scientifically to creating a taut skin by shaping the dough into a ball or similar. But I still cannot see how or why this would improve the loaf shape, oven spring or any other quality of the finished loaf. In particular, in all my years of working with soft doughs (70+% hydration), I have never been able to prevent dough spreading by shaping it (in any case, shaping soft, sticky dough is very difficult). Does anyone know what the scientific basis for this idea is?