We have mapped the formation of tars during white oak thermochemical conversion using a bench scale laminar entrained flow reactor (LEFR). White oak particles (80 mesh, <180 μm) were pyrolyzed under conditions not limited by heat transfer. Measurements were made with residence times of 0.2, 0.4, 0.6, and 0.8 s, between 500 and 900 at 100 °C increments, and with residence times of 1 s at temperature from 450 to 950 °C at 25 °C increments. Products were monitored with a molecular beam mass spectrometer (MBMS), and the mass spectra were analyzed using model-free multivariate analysis (multivariate curve resolution). Six groups of correlated masses were identified that suggest the mechanisms of pyrolysis and gasification. The first group of masses (lowest temperature) is associated with primary species from lignin and hemicellulose, followed by cellulose products. The next two groups (increasing temperature) are composed of secondary products resulting from the cracking of carbohydrate vapors and the cracking...