Spectra at the expected velocity of CH₃OH line emission in the HD 163296 disk showing non-detections from aperture-masked image cubes using an 8′′ diameter circular aperture (black) and Keplerian-masked image cubes (magenta). The two bottom spectra are observed in band seven in 0.139 km s⁻¹ channels while the two top spectra are in band six in 0.303 km s⁻¹ channels. The horizontal gray dashed line represents the spectrum baseline, which is offset by 200 mJy for each line. The vertical red dashed line shows the systemic velocity at 5.8 km s⁻¹ (Qi et al. 2011).