Vacuum Purging BHO
2 min

BHO Science: Why You Should Be Vacuum Purging & How to Do It

2 min

If you are a fan of butane hash oil (also known as BHO and dabs), then chances are you can spot some low grade BHO from a mile off. Whilst there are many factors that contribute to low quality BHO, none is more prevalent or important as proper vacuum purging.

Unless you vacuum purge your BHO, it will turn out grey, bad tasting, and full of impurities – both degrading the quality of the experience, as well as your health.The best way to purge your BHO is with a vacuum oven, and a good one at that.

When you first start out making BHO the initial outlay required to buy a decent vacuum oven can be a bit daunting, but if you buy a cheap one off eBay, or worse yet, don’t use anything at all, the quality of your product is going to be severely hit.

What Does Vacuum Purging Do Exactly?

What Does Vacuum Purging Do Exactly?

Vacuum purging is so important to BHO production because they help boil away the solvents and impurities that are a part of the creation process – leaving behind a pure, safe and tasty BHO. Vacuum purging places your oil under an atmospheric pressure. This pressure lowers the effective boiling point of each of the compounds within your BHO, allowing certain ones to be cold boiled away without potential damaging the others.

Of course, if you can’t afford the cost for a vacuum oven, or don’t have the space for one, then it is possible to make your own purging system. Whilst this may not result in as good a quality of product as using a vacuum oven would, it is still better than not doing any purging at all.

How To Vacuum Purge BHO

You will need:

  • A large Pyrex dish

  • A heat-safe vacuum chamber

  • A vacuum pump

  • A large BHO mat (slick mat)

  • Electric hot pan

  • Electric Griddle

  • Thermometer gun

DabbingView Dabbing Products


  1. The first thing to do is set up your extraction tube, and fill it with bud. The more tightly packed the better.

  2. Set up your electric hot pan – either outdoors or in a well-ventilated area - and fill it with water. Float your Pyrex dish in it and turn up the heat to bring the water to roughly 40 degrees Celsius.

  3. Blast your bud and extract your BHO directly into your Pyrex dish.

  4. Allow the hot water bath to purge and evaporate away the excess liquid butane – waiting for the reaction to slow. During this time, agitate the liquid with a fork to help remove bubbles. This should take around 10 minutes.

  5. Now scrape out your BHO and transfer it onto your BHO mat in a thin layer.

  6. Place this in your vacuum chamber and set up the vacuum pump.

  7. Place the vacuum chamber on your griddle and heat it up to 40-43 degrees Celsius. Use your thermometer gun to keep an eye on the temperature in the vacuum chamber.

  8. Set the vacuum to 27” HG and watch the BHO closely to make sure it doesn’t over puff or explode (it may puff a little).

  9. If this is all ok, release the vacuum, then set it to 29” HG at this temperature. Leave it for 30 minutes, depressurise, and then back to 29” HG. Repeat this process until you are happy that the BHO has been fully purged. This could take up to 2 hours.

  10. The end result should be some clear glass-like brown/golden BHO! Once done, release the vacuum and store!

There you have it! You have successfully vacuum purged your BHO and created a much safer, purer product! The above method is a very basic, DIY method, and is really the minimum you should be doing. It is possible to get much more complicated, with more technical equipment, but if you can’t get your hands on any, or can’t afford it, then the above is a good starting point.

Luke Sumpter
Luke Sumpter
With a BSc (Hons) degree in Clinical Health Sciences and a passion for growing plants, Luke Sumpter has worked as a professional journalist and writer at the intersection of cannabis and science for the past 7 years.
Headshop Products
Search in categories