why we test (and test again)
Castor oil is everywhere. Verified castor oil is not. Most brands ask you to take their word for it. We would rather show you the certificate.
Lot B001 is our baseline lot, the one every future batch gets measured against. It went to Contract Testing Laboratories of America, who hold ISO/IEC 17025 accreditation. They ran it for heavy metals, microbial safety, pesticide residue, oxidative markers and residual solvents.
Some of those came back exactly as we hoped. One did not, and one is being re-run. Both are below, because a testing page that only shows the good results is not a testing page.
what we test for
Heavy metals screening (USP <233>)
Lead, arsenic, cadmium and mercury, all of which are toxic and all of which your skin can absorb.
Lot B001: all four below 0.001 ppm. That is 50 to 100 times under the limits we set. Arsenic and lead specified at 0.1 ppm, cadmium and mercury at 0.05 ppm, every result under the method's detection floor.
Microbial safety testing (USP <2021>, <2022>, <62>)
What matters on something you put near your eyes, on your scalp and on your skin.
Lot B001: total aerobic count under 100 cfu/g, yeast and mould under 10 cfu/g. E. coli, Salmonella, Staphylococcus aureus and Pseudomonas aeruginosa all absent.
Multi-residue pesticide screening
LC/MS/MS across 189 compounds, from abamectin to triflumizole.
Lot B001: none detected, at a detection limit of 0.1 ppm.
Oxidative stability
Peroxide value by AOAC 965.33, acid value by AOCS Ca-5a-40, p-anisidine by AOCS Cd 18-90, moisture by USP <731>. Together these show whether an oil has begun to turn.
Lot B001: acid value 1.61 mgKOH/g against a limit of 2.0. p-anisidine under 1.0 against a limit of 2.0. Moisture 0.09 percent against a limit of 0.2.
Peroxide value came back at 7.534 meq/kg against our limit of 5.0. That is a fail and we are not going to dress it up. The laboratory attributed it to the sample container being opened repeatedly for other tests before the peroxide run, which is plausible given the other three oxidative markers all passed comfortably. Plausible is not proven. We have agreed a handling protocol with the lab that runs peroxide first, on receipt, from a sealed container, and we are submitting fresh material. The re-run result will be published here, whatever it says.
Residual solvent testing (USP <467>)
Covering 44 solvents. Cold pressing should leave none.
Lot B001: 41 of 44 not detected, including benzene, hexane isomers, dichloromethane and toluene. Three were detected at trace level: 2-propanol at 61.5, pentane at 18.0 and hexane at 6.8 micrograms per gram.
We do not yet know whether those three came from the oil or from the sampling glassware, because no method blank was run alongside them. A blank is the control that tells you which. We have commissioned a second accredited laboratory to repeat the panel with a method blank reported next to the result. Until that comes back we are not claiming this oil is solvent free.
Fatty acid composition (GC-FAME)
GC-FID of fatty acid methyl esters, comparable to USP <401>, to confirm the oil's profile is ricinoleic acid dominant and has not been cut with anything cheaper.
In progress. Booked with an accredited laboratory, results published when they land.
