Residual solvents

Residual solvents refer to trace amounts of extraction chemicals like butane or propane left behind in concentrates after purging. Testing is required in legal markets to ensure residuals fall under acceptable state thresholds. Too much residual solvent can be harmful if smoked. An excess of leftover solvents indicates poor processing. When making butane hash oil, cannabis is washed in liquid butane, then vacuum purged to evaporate the butane - but residuals may linger. The highest quality extractors eliminate all residuals through meticulous technique. Consumers can avoid residual solvents entirely by choosing solventless concentrates like rosin. If purchasing from licensed shops, checking for state compliance testing provides assurance. If buying from unlicensed sources, it is impossible to verify the level of potential residuals or other contaminants.