Standard Operating Procedure: CRC Color Remediation

SOP Number:

Version: 1.0

Effective Date:

Prepared By:

Approved By:

Review Date:

1. Purpose

This SOP defines the procedure for color remediation (CRC) of hydrocarbon cannabis extract using an in-line filtration column packed with adsorbent media. The procedure covers media selection, activation, stack construction, the filtration pass, and quality control. CRC is run as part of a closed loop hydrocarbon extraction, with the solvent-extract solution passed through the media column before solvent recovery. All operations must comply with local fire code, C1D1/C1D2 classification requirements, and applicable state cannabis regulations.

2. Scope

Applies to in-line color remediation of butane, propane, or butane/propane extract solutions within a closed loop system. Covers the use of adsorbent media stacks (activated carbon, bentonite/bleaching clay, silica gel, and magnesium silicate) to remove pigments, lipids, and polar impurities. Does not cover the base extraction procedure (see BHO Closed Loop Extraction SOP) or post-CRC purging beyond the CRC-specific QC steps below.

CRITICAL SAFETY: CRC is performed inside a pressurized hydrocarbon closed loop system. Butane is an extremely flammable gas (NFPA 704: Health 1, Flammability 4, Instability 0). All work must occur in a C1D1 or C1D2 classified room with active ventilation, calibrated LEL gas detection, and explosion-proof equipment. Adding a packed CRC column raises system flow resistance and can increase operating pressure. Confirm your column and clamps are rated for the resulting pressure before the run.

3. Equipment & Materials

Item	Specification	Notes
CRC column / spool	ASME-rated, in-line between material column and collection pot	Sized to extract volume. Inspect clamps and gaskets before every run.
Filter screens	25 micron and finer at column outlet; support screen at inlet	Fine media migrates. A single micron gap sends powder into your collection pot.
Activated carbon (T5 or equivalent)	Decolorizing grade, activated/dried	Strongest decolorizer. Also the most aggressive at stripping cannabinoids and terpenes. Use sparingly.
Bentonite / bleaching clay (B80 or equivalent)	Acid-activated montmorillonite	Adsorbs chlorophyll and pigments. The workhorse of most stacks.
Silica gel 60	40-63 micron, 60 Angstrom pore	Removes polar impurities and residual moisture. Protects the other media from water.
Magnesium silicate (Magsil / Florisil)	60-100 mesh	Polar adsorbent. Optional. Good for lipids and oxidized compounds.
Drying oven	Capable of 200-250F stable	For media activation. Wet media is the single most common CRC failure.
Scale	0.1g resolution	Media is dosed by weight relative to input. Track it in the batch record.
LEL gas detector	Calibrated for butane, alarm at 10% LEL	Active before, during, and after every run. Non-negotiable.
PPE	Safety glasses, nitrile gloves, N95 for media handling, anti-static lab coat	Fine clay and carbon dust is a respiratory hazard. Mask up when packing.

4. Media Stack Reference

Each medium does a different job. The stack is built so the solvent solution passes through them in a deliberate order. A typical starting point is listed below; adjust ratios to your input color and target.

Medium	Primary Function	Typical Share of Stack	Tradeoff
Silica gel 60	Removes moisture and polar impurities; protects downstream media	20-40%	Minimal cannabinoid loss. Skipping it lets water deactivate your clay and carbon.
Bentonite / B80	Adsorbs chlorophyll, pigments, and general color	40-60%	Moderate. The safest bulk decolorizer per gram.
Activated carbon / T5	Aggressive decolorizing for the last of the color	5-20%	High. Strips cannabinoids and terpenes fast. Overdosing bleaches out potency and flavor.
Magnesium silicate (optional)	Lipids and oxidized/polar compounds	0-20%	Low to moderate. Useful on older or lipid-heavy crude.

Dosing guidance: Total media is typically 15-40 grams per 100 grams of crude extract, or roughly 1-3% of input biomass weight. Start on the low end. You can always run color-heavy extract through a second, smaller pass. You cannot put stripped cannabinoids and terpenes back.

5. Media Activation

Wet media is the number one cause of failed CRC runs. Clays and silica pull water from the air. Water in the media deactivates its adsorption sites and can carry moisture into your extract, causing emulsions and haze. Activate media the same day you run it.

1 Spread media in a thin layer on a clean tray. Do not mix media types yet.

2 Dry / activate silica and clays at 200-250F for at least 1-2 hours. Activated carbon may be dried at the same temperature. Longer drying at temperature improves consistency.

3 Cool in a sealed container. Let media cool in a closed vessel or desiccator so it does not re-adsorb ambient moisture before packing. Keep it cold if your process runs cold solvent.

6. Pre-Run Checklist

DO NOT PROCEED if any item below is not confirmed. A packed CRC column changes your system pressure profile. Treat it with the same rigor as the base extraction run.

☐	Check	Criteria
☐	LEL monitor powered on and calibrated	Reading 0% LEL at ambient. Alarm set at 10% LEL.
☐	Ventilation running, negative pressure verified	Minimum 12 air changes per hour confirmed.
☐	Media activated and cooled dry	Dried at 200-250F same day, cooled sealed.
☐	Outlet filter screen 25 micron or finer installed	No gaps. Prevents media powder reaching collection.
☐	CRC column clamps torqued, gaskets inspected	Tri-clamp hand-tight plus quarter turn. No worn gaskets.
☐	Pressure test (nitrogen) with CRC column in line	Holds 150% max operating pressure for 10 minutes, no drop.
☐	Media doses weighed and logged	Each medium recorded in batch log by weight.
☐	Collection vessel clean and dry	No residual solvent or extract from previous run.

7. Packing the CRC Column

4 Install the base support screen at the outlet end of the column.

5 Load media in order of flow. With top-down flow, pack so the solution meets silica first (moisture and polar removal), then bentonite/clay (bulk color), then activated carbon (final decolorizing) last. This order protects the aggressive carbon from water and spreads the color load across the gentler media first.

Pack evenly, no channeling. Tap and settle each layer. Air channels or loose packing let solvent bypass the media, so part of your extract passes uncleaned while the rest over-contacts. Uneven packing is why one run comes out clear and the next comes out streaky with the same recipe.

6 Install the fine outlet screen and seal the column. Torque all clamps. Confirm gaskets seated with no gaps.

8. Running the CRC Pass

7 Route the extract solution through the CRC column between the material column and the collection pot, per your system plumbing. Keep the solvent cold to preserve terpenes and limit cannabinoid pickup by the carbon.

8 Control flow rate. Contact time controls how much the media adsorbs. Too fast and color slips through; too slow and the carbon strips potency. Aim for a steady, moderate flow rather than a fast dump.

Observation During Pass	Meaning	Action
Solution runs clear/light gold	Stack is working as intended	Continue. Note recipe for repeatability.
Solution still dark at outlet	Under-dosed media, channeling, or exhausted media	Plan a second smaller pass. Do not simply slow flow to a crawl (strips potency).
Solution nearly colorless / pale	Over-decolorized	Reduce carbon share next run. You are likely losing terpenes and some cannabinoids.

9 Proceed to solvent recovery and purging per the base extraction SOP once the solution has passed through the CRC column.

9. Quality Control

QC Checkpoint: CRC is a cosmetic and purity step, not a license to hide bad starting material. Compare pre-CRC and post-CRC potency where possible. A well-tuned pass typically costs a few percentage points of total cannabinoids. Double-digit potency loss means the carbon share is too high or contact time is too long.

QC Check	Target	Why
Color	Clear to light gold, consistent batch to batch	The point of the step. Consistency signals a controlled process.
Potency loss (pre vs post CRC)	Single digits (typically 2-8%)	Larger losses mean the stack is stripping cannabinoids, not just color.
Residual solvent	<500 ppm on finished product (most states)	CRC does not replace proper purging. Test before release.
Media particulate	None visible in finished extract	Powder breakthrough means a screen gap. Inspect and re-run.

Regulatory note: Some markets restrict or scrutinize CRC because it can mask remediated or low-grade material. Know your state’s stance and your brand’s position before running CRC on product intended for sale. Never use CRC to disguise contaminated, moldy, or failed material.

10. Troubleshooting

Symptom	Likely Cause	Corrective Action
Extract still dark after full pass	Under-dosed media, exhausted media, or channeling	Increase clay share, repack evenly, or run a second smaller pass. Verify media was activated dry.
Major potency loss (double digits)	Too much activated carbon or contact time too long	Cut carbon share, speed flow slightly, shift color removal to bentonite.
Haze or emulsion in extract	Wet media carried moisture into the solution	Re-activate media at 200-250F. Add or increase silica in the stack.
Media powder in collection pot	Outlet screen too coarse or a screen gap	Install 25 micron or finer screen. Inspect seating. Re-filter the affected batch.
Streaky/inconsistent color one run to the next	Uneven packing, channeling, variable flow rate	Pack and settle each layer evenly. Standardize flow. Log media weights every run.
System pressure spike during pass	Media too fine or packed too tight, screen clogging	Reduce fines, loosen packing slightly. If pressure approaches rating, STOP and depressurize safely.

11. Revision History

Version	Date	Change Description	Author
1.0		Initial release