Vegetable Glycerin vs Propylene Glycol THC Extraction (Is PG or VG the Best Method?)

After publishing our fantastic results on infusing in the Nova, we were flooded with our curious customers’ questions. People wanted to know if they could extract THC and CBD from decarbed flower or trim using Propylene Glycol (PG) and Vegetable Glycerin (VG). These two are often referred to PG and VG, respectively, and are found in many food, OTC and beauty products.

Like the decarb process, infusion rates in PG and VG have remained to the general public an unsolved mystery, mainly owing to there being little to no real testing to show how PG and VG perform.

As usual, we rose to the challenge and tested PG and VG samples extracted using the Nova. With our lab results in hand, we’re excited to share our findings with you and expand your cannabis knowledge – the rest of this post will present the results of our PG and VG testing.

PG or VG for THC Extraction?

THE BIG REVEAL: PG wins! Using PG resulted in over 90% infusion rate. VG didn't even come close, and had a very poor infusion rate at less than 10%.

The simple decarb and infusion process:

  1. Place the decarbed cannabis and one ounce of PG into a tempered glass jar or our Concentrate and Infusion Sleeve.
  2. Put the jar back into the decarboxylator for a second cycle. The second cycle will pull the THC or CBD from the plant into the propylene glycol.
  3. When the process is complete, strain the plant material from the PG.
  4. The infused PG can then be used to make any PG-based cannabis product.

Propylene Glycol THC Extraction is a Very Efficient Method - Vegetable Glycerin is Not!

When it comes to propylene glycol (PG) and vegetable glycerin (VG), there's no competition. VG did not infuse well at all, but with PG, we were able to get over 90% of the THC from the decarbed flower into the PG, infusing just 1 gram of decarbed flower to 1 ounce of PG.

Compare that to VG, which pulled less than 6% of the THC from the decarbed flower, infusing 1 gram of the same strain of decarbed flower into 1 ounce of VG.

Out of a total 197.8mg of available THC in the 1 gram of bud after a decarb cycle in the decarboxylator, the VG infusion only resulted in 11.34mg of THC in the one ounce of VG used. Compare that to 179.7 mg THC in the once ounce of PG.

You can increase or decrease the potency by using more or less PG/VG or cannabis. Check back soon for a video on maximum infusion potential and best practices for PG & VG.

Like with any infusion, it’s necessary to decarb BEFORE you infuse if you want an active end product.

*Please note that this post is about infusing/extracting THC and CBD from decarbed flower, trim, and other material that would be then be strained from the PG and VG after infusion. If you are decarbing concentrates, you can easily mix those with VG and PG in a second cycle in the Nova and get great results, because there is no extraction necessary. Making products with concentrates is a heating/blending process rather than an infusion/extraction process.

See below for the numbers compared in chart form.

Sample Acid THCA ACtive thc Total potential active thc Total infusion Testing Results
1 gram of Decarbed Dragon's Bait flower 2mg 196mg 197.8mg n/a
1 gram of Decarbed Dragon's Bait infused into 1 ounce PG Not detected 179.74mg 179.74mg 90.8%
1 gram of Decarbed Dragon's Bait infused into 1 ounce VG Not detected 11.34mg 11.34mg 5.7%

*Total Potential THC = THCA x .87 + THC, and represents tha maximum amount of THC in the plant, if it is able to be perfectly activated. When THCA converts to THC, the acid molecule (carboxyl group) is released, reducing the total molecule weight by 13%. You can get the full potential THC with precision decarboxylation. In lab results, look for the "Max THC" field to find the amount of total potential THC.

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