Better bho thru chemistry


ganja farmer
May 29, 2008
Reaction score
Hi all, wanted to share some learning I've been doing on butane concentrates. DISCLAIMER: Full melt bubble and subcritical CO2 are both better concentrate options. Also, I'm not affiliated with freshlabzz in any way just copied certain aspects of their setup

Making BHO is dangerous/illegal in certain areas, so.... DO IT RIGHT!

You don't need a fancy $30k extractor to churn out top quality shatter, more like a few hundred dollars. The method thats worked best for me is a open blast dual solvent extraction followed by thin film vacuum purging.

A concrete = concentrate from fresh frozen material
An oleoresin = concentrate from dried material
An absolute = concrete or oleoresin "winterized" to remove plant waxes, etc

I highly prefer consuming absolutes from fresh frozen (not decarboxylated) material, much higher concentrations of volatile mono and sesqui terpenes, TASTY!!

I will assume that you know the basics of how to safely open blast and focus on small details that affect the final product.

1. Get a 14" diameter tall stainless pot with rubber lip (google freshlabzz for pic). put a pyrex pie dish in the pot and blast onto this. You will want the pot to remain covered while blasting to prevent particulate matter in the air from getting to the product while still allowing the residual butane to escape.

2. Water is slightly soluble in butane but we don't want any water in the final product, so the tall pot is crucial to preventing moisture from the atmosphere from contacting the raw product. Since butane is heavier than air, it displaces the atmosphere in the pot keeping the product "dry".

3. The pot should sit in an oil bath on a heat mat at LOW heat 100F max for inital purging. Then redissolve the crude product in 100% anhydrous ethanol (most people use plain everclear, which contains water that we don't want in the product). NOTE: you cannot buy anhydrous EtOH, but you can make it. The easiest way to make anhydrous ethanol is by buying vodka or everclear and adding a molecular sieve called Zeolite. (Absolute EtOH should be used immediately or stored under inert atmosphere because it highly hygroscopic and will pull water out of the atmosphere) Alternatively, if your vacuum pump pulls down to 70 torr you can distill off the azeotrope.

4. The ethanol mixture should be winterized to remove non-psychoactive plants waxes and lipids. You can either buy a $10k freezer that goes to -50C or put your container holding the crude oil into a homemade cold bath for $10. Dry ice and isopropyl cools to -77C while dry ice and ethanol cools to -72C. Thats really cold, wear protective equipment! The plant waxes will solidify and should be vacuum filtered using a Buchner funnel

5. Still in the same pot and pyrex pan we put a polycarbonate lid with vaccum pump (see freshlabzz for pic) and do thin film vacuum. It is basically cold purging a very thin layer for maximum surface area. The ethanol is removed easily under reduced pressure taking all residual butane with it.

5. You MUST have a cold trap, or cold finger in between your pot and the vacuum pump so the butane condenses into a liquid and does not enter the vacuum pump. A cold trap can be made using dry ice/isopropyl alcohol or dry ice/ethanol.

I know this is not comprehensive but just minor details a lot of people miss.

Last thought, learning a bit of chemistry on your own does not mean you are now an "extract artist". People who call themselves that are huge tools because they think they know everything when in reality there is ALWAYS more to learn about cannabis no matter how long you've been at it.

Happy dabbing! -greenfriend


Well-Known Member
May 18, 2011
Reaction score

its friday night, and im feeling alright... Gonna have to re read this again later :rofl:

Latest posts