Butane Extraction Tips

Supplement - Extraction Essentials

from Brad Robertson, Co-Founder, Guild Extracts

The Guild offers a wide range of products, but specializes in its house-made hydrocarbon extracts.
Photos courtesy of Guild extracts

TIP: A spray bottle of soapy water can help quickly identify and locate any leaks at joints or seals in a pressurized system.

“Making sure your system is free of leaks is important to ensure that no oxygen is in your system with your solvents and no gaseous solvents are with your oxygen in your workspace. Fire requires three elements to occur: oxygen, fuel and spark. Remove any of these elements, and fire cannot occur. Upon initial assembly, pressurize your entire system to 25 psi to 50 psi overnight to help ensure a leak-free system.”

TIP: Grind your plant material to about the consistency that you would roll in a joint.

“How you prepare your cannabis for extraction can greatly influence your end product. If the material is ground too finely, more of the cell walls of the plant material can be damaged—opening undesirables up to exposure to the solvent [and] extracting them [along] with your more desirable compounds; not finely enough, and you’re not making efficient use of space in your column.”

TIP: Pack (but don’t compact) your column.

“Be mindful when packing the column. Pack the column to the point that you feel resistance, but the plant material springs back. Pack it too tightly or too loosely, and you’ll get channeling. Channeling occurs when the solvent takes the path of least resistance around plant material that must come in contact with the solvent.”

Left: Crystallized THCA. Tetrahydrocannabinolic acid (THCA) is a non-psychoactive form of THC that converts into THC through decarboxylation (heating). Bottom: The Guild sells its house-made hydrocarbon extracts, including shatter (seen below), at its San Jose dispensary and partner businesses.

TIP: Run until the solvent appears colorless.

“When observing your solvent flow through the sight-glass, it should appear yellow as it first passes through the plant material. Once it’s grabbed everything good and deposited it into your collection pot, the solvent will appear colorless.”

TIP: Run cold.

“When extracting from cannabis, the colder, the better. Water and butane have relatively low co-solubility (around 61 mg/L at 20°C/68°F). Locking up moisture in the plant material by making it ice avoids the water mixing with your butane and acting as a solvent on less desirable, water-soluble compounds like chlorophyll—which can contaminate your final product. Running with an in-line desiccant dryer will also keep unwanted water from your gases, avoiding undesirables in your finished product and adding life to your expensive pumps.”

TIP: Consider nitrogen assist.

“Solvent flows through your closed-loop extraction system as a result of pressure differential. When running under cryogenic conditions, solvents can all condense to a liquid state. This creates equilibrium in the system and no pressure differential to move your solvent through your plant material. Nitrogen, however, stays in its gaseous form at temperatures as low as -200°C and can be used to create the needed pressure to get things moving. You’ll need to ‘burp’ it from your gas storage tanks when you’re finished.”