Studies of the smoking process for foods. I.—the importance of vapours

Wood smoke consists of minute, light‐scattering particles and invisible vapours. The direct deposition of smoke particles makes a negligible contribution to the smoking of fish within the normal range of curing temperatures (32–82°) and for all stages of dryness of the fish up to a pre‐smoking weight loss of about 30%. The mode of deposition of smoke on fish appears to be one of vapour absorption, in which the surface and interstitial water of the fish acts as the principal absorbent. Fish ‘cured’ in the vapours which remained after visible particles of wood had been electrically precipitated were indistinguishable in colour, flavour and keeping quality from normally‐smoked fish. Analyses of normally‐ and vapour‐smoked bacon suggest that bacon smoking, like fish smoking, mainly involves a vapour absorption process.