Sugars are heavily caramelized (read as burned) and are degraded; the woody bean structure is carbonizing, the seed continues to expand and loose mass, the body of the resulting cup will be thinner/lighter as the aromatic compounds, oils, and soluble solids are being burned out of the coffee and rising up to fill your house with smoke. 474 is well beyond any roast I do on the Probat. Second crack is well finished. I will go as high as 465 on a couple blends, and that’s my limit.