I’ve received quite a lot of feedback on this the last several days, from both physicists and bakers (interesting combo) from as close as Indianapolis and as far away as New Zealand. Oddly, no real consensus emerged among them, even within the (albeit small) groups. While it’s indisputably true that condensation (a heat-bringing process) occurs when steam is injected into an oven, it’s also indisputably true that evaporation (a heat removal process) happens very soon afterward. I’ve received some rather long — and technical — treatises on both phenomena since Friday. However it was Christian, an ingredient scientist (a baking and frying specialist and a long-time business acquaintance), who has me leaning hard to my friend Hans’ point of view. He writes:
The central issue as your reader pointed out is heat transfer. Steam raises the surface temperature of a loaf of bread faster than evaporation can cool it. Without steam, the surface of a loaf inserted into a 475-degree oven takes on average four minutes to reach 200 degrees. With steam, the loaf will reach 200 in just over one minute. Note that there’s an important difference between spraying the sides of an oven (which creates actual steam) and spraying the bread itself (which leads to more evaporation). The former adds heat, causing the gas cells in the loaf to expand faster. The latter does the reverse.
It seems to me that Christian may have identified the rub here. Which is to say that there’s a difference between introducing hot steam into an oven and simply adding moisture to it, actions which create very different outcomes. Which means that we bakers need to be careful to always spritz the sides of our ovens when baking bread, and not the bread itself.
Well…that’s good enough for me! Thanks Christian! One more big-time bit of baking dogma bites the dust. Of course, if there’s anybody out there who cares to continue the argument, I’ll be more than happy to receive your emails (and post them).