The easiest (and only) characteristic of homebrew that I can measure is gravity. Easily done with a hydrometer or a spectrometer. The other day, just for the sake of curiosity, I looked up how to measure bitterness units. The only hits that I got were about how to calculate it, not measure it. Does anyone know how a homebrewer can measure the IBU of a beer? And while we're on the subject, is it practible or possible for a homebrewer to measure color? How's that for a topic, jmcnamara??