I researched the net about 3yrs ago trying to pin down the various grades of castor oil and came to realize its an industry shrouded by the market and source just like coffee is. Bakers AA is a relatively low grading and nothing special except to say its a "first pressed" grade. "Pharmacy grade" is also a broad term and not all are necessarily equal. "Technical Grade" as best I can tell is the same as "Baker AA" and is common in medical laboratory supply. The moisture content being low (desirable) and probably more consistent than a AA designation. Seems like it was $25/gallon when I bought some and it has worked just as well as the Sig AA stuff I used before.

But I've never scratch blended any fuel, only added to retail fuels to bring the % and type of oil blend to a desired point.

Regards,

Clay