Noun
liquid smoke (uncountable)
A substance produced by either passing smoke from wood-burning through water, or capturing such smoke and later mixing it with water, used for food preservation and flavoring.
Liquid smoke is often used by gardeners to assist in the germination of these species. citation Sterile seeds Seeds may be sterile for few reasons: they may have been irradiated, unpollinated, cells lived past expectancy, or bred for the purpose. Source: Internet