Butane hash oil (BHO) is a favorite among cannabis enthusiasts and industry professionals for its intense potency and smooth texture.

Achieving this high-quality concentrate safely and efficiently is a complex process, made simpler and more reliable with advanced closed-loop extraction techniques.

Closed-loop extraction methods curb the hazards associated with butane, a highly volatile solvent, and recycle it to minimize waste.

What Is Open Loop Extraction?

Open-loop extraction is a basic form of solvent extraction used to produce cannabis concentrates, including BHO. This method involves passing a solvent, typically butane, through cannabis plant material to dissolve beneficial compounds like THC and CBD.

However, unlike more advanced systems, open-loop extraction does not completely contain the solvent within the system. Instead, the solvent is exposed to the air and can evaporate into the environment during the process.

Safety is the main concern with open-loop systems. Because the solvent is exposed, there is a significant risk of butane gas accumulating, which can lead to explosive situations if not properly ventilated or conducted.

While open-loop systems are less expensive and simpler in design, which makes them accessible for amateur use and smaller-scale operations, their inherent risks and inefficiencies make them less suitable for commercial production.

What Is Closed-Loop Extraction?

Closed-loop extraction is a refined technique used to produce high-quality BHO by efficiently managing butane.

Unlike open-loop systems where the solvent can escape into the air, closed-loop systems completely contain the solvent within a sealed environment throughout the extraction process. This method reduces the risks of explosions by preventing any butane from leaking out.

This entire system is often housed within C1D1 enclosures, which are engineered to meet rigorous safety standards for environments with flammable gases or vapors. They provide a compliant environment for electrical and mechanical systems in explosive conditions.

The process involves several critical components that work in harmony, including the material column where the cannabis is placed, the solvent tank that holds the butane, the collection chamber for gathering the extracted oil, and the recovery tank to condense and recycle the butane.

By tightly controlling exposure to the solvent and recycling it within the system, closed-loop extraction offers a safer approach to producing BHO, making it the preferred method among professionals in the cannabis industry.

Closed-Loop Extraction Equipment

Closed-loop extraction equipment consists of several key components, each designed to handle the solvent and cannabis material securely throughout the extraction process. Here's an overview of the main pieces of equipment involved:

Material Column

The heart of the system, the material column holds the cannabis material. It is typically made from stainless steel to withstand high pressures and prevent any chemical reactions with the solvent. Many columns are equipped with temperature-control jackets to optimize efficiency.

Solvent Tank

A pressurized container that stores the solvent, usually butane or propane, before it is introduced into the material column. This tank is also constructed from materials that can handle the low temperatures and high pressures associated with the solvent.

Collection Chamber

After the solvent extracts the desired compounds from the cannabis material, the resulting mixture moves to the collection chamber. Here, heat is applied to evaporate the solvent, which is then captured and condensed back into liquid form in the recovery tank, leaving behind the concentrate.

Recovery Pump

The recovery pump maintains the flow and pressure necessary to transport solvent vapors from the collection chamber to the recovery tank. It is designed to handle the volatile nature of solvents like butane for a consistent and safe transfer under controlled conditions.

Recovery Tank

This component is used for solvent recovery. It cools the vaporized solvent, converting it back into a liquid. This minimizes waste and environmental impact and reduces operational costs by recycling the solvent.

Vacuum Pump

A vacuum pump is used to create a negative pressure environment within the system. This helps in moving the solvent through the system and helps with the final purging of the concentrate. This critical step guarantees no residual solvents are left.

Vacuum Oven

Used in the final purification stage, the vacuum oven removes any remaining solvents from the concentrate by applying controlled heat and vacuum pressure. The precise control over temperature and pressure also preserves the delicate terpenes and cannabinoids

Control System

Modern closed-loop systems include sophisticated control systems to monitor and adjust temperatures, pressures, and flow rates throughout the extraction process. This automation maintains consistent quality and safety.

Color Remediation Column (CRC)

A filtration unit in the closed-loop system, the CRC uses adsorbents like activated clay to purify the BHO by removing impurities and improving color clarity. This step provides a premium-quality final product.

BHO Closed-Loop Extraction Process

Closed-loop extraction is a precise, multi-step process that efficiently and safely extracts cannabinoids and terpenes from cannabis material using butane. Here’s a closer look at each step in the process:

Loading Material

The process begins with finely ground cannabis plant material being loaded into the extraction column. This column is designed to contain the plant matter securely while allowing the solvent to pass through it.

Solvent Introduction

Butane, the solvent used in this process, is introduced into the system from a pressurized tank. It travels through the extraction column where it dissolves the desirable compounds (cannabinoids and terpenes) from the plant material.

Separation and Collection

As the butane extracts these compounds, it creates a solution that flows into the collection chamber. Here, the mixture is gently heated, which helps evaporate the butane, leaving behind the concentrated cannabis oil. The heating needs to be carefully controlled to prevent degradation of the delicate compounds.

Solvent Recovery

The evaporated butane is captured in a condenser, cooled, and converted back into liquid form. This recycled butane can be reused in subsequent extraction cycles, minimizing waste and reducing operational costs.

Purging

Any residual solvent left in the cannabis oil is removed in the purging chamber. Under vacuum pressure and controlled heat, trace amounts of butane are eliminated, ensuring the final product is safe and pure. This step helps maintain the quality and safety of the concentrate.

Quality Control and Storage

The final product is tested for purity, potency, and residual solvents to meet quality standards. Once approved, it is carefully stored in airtight containers to preserve its chemical integrity until it can be processed further or prepared for sale.

The Closed-Loop Advantage

Closed-loop extraction sets a high standard in cannabis concentrate production by efficiently controlling solvent use and maximizing recovery. As demand for quality concentrates grows, closed-loop technology maintains compliance with stringent safety standards and delivers consistently pure products.