Scientists in Macbethland have figured it out, but they were using a toaster-oven. I am using a toaster!
==========================http://hub.jhu.edu/magazine/2013/spring/engineering-perfect-toast
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Minsky concentrated on toast, which turns out to be tricky. Blame it on browning. "Browning is a positive feedback process that is actually exquisitely sensitive," he says. "As the toast becomes brown, or darker, it starts to absorb much more infrared radiation from the heating elements, thereby quickening the heating process, causing it to brown faster and faster." A few extra seconds or degrees of heat, he says, can make or break a piece of toast. The perfect amount of browning is essential, Cowan says, to achieve the Maillard reaction—the chemical reaction between an amino acid and a reducing sugar that in bread's case leaves a brown color.
Some researchers in the United Kingdom already had uncovered, or so they claimed, the recipe for perfect toast: heat at 154 degrees for 216 seconds. Using this as a base, Minsky and his team went to work tricking out an off-the-shelf toaster oven. They inserted a precision thermometer and connected it via relay to a controller that managed the heating process. The students then programmed the controller to maintain a constant temperature for the precise desired amount of time. The controller turned the heating element on and off if the interior conditions went above or below the specified temperature.
The results, Minsky says, were delicious. "It was shockingly good. We thought the first slice might have been a fluke, but we used two whole loaves of bread and every piece we made was light and golden brown, just the perfect amount of crispiness."
One small step for mankind.
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They only used one type of bread!
What would the result be with switching from white to wheat to rye or muffin?