Step 1 - Wash

Step 1 - Wash

Introduction

Alcohol extraction is simple and straight forward. Simply wash the plant with the highest proof alcohol and you get a lot of plant resins. The trick is to do it in such a way to take the best and leave the rest. 

Creating a clean golden oil extract is the Holy Grail of solvent extraction but it requires further processing to remove color. Simply washing frozen plant with frozen alcohol is not enough. Current color remediation involves the use of Activated Carbon, Diatomaceous Earth, under vacuum to filter out the color. Now a days, golden oil is usually sourced from BHO or C02 extract as these processes create superior starting oil. A future post, "The Art of the Wash" will be published with optimal color remediation steps. 

For this audience, the easiest approach is the best approach, and that is to use a fast room temperature extraction. The superior cleanup in the following steps makes this work as well as a QWET or QWISO wash. Before this process, these fast frozen extractions were favored to avoid waxes but didn't avoid color. 

Solvent Selection

The purpose of a fast extraction is to extract only the 'low hanging fruit', but this leaves some resins behind for a second soak. 99% alcohol, whether Isopropyl or Ethanol, is necessary for best results. The lack of water content is great for dissolving surface lipids, but also limits the solvent's ability to penetrate the plant. 91% Isopropyl and 95% Ethanol have water content that allows penetration of the plant which then dissolves unwanted additional compounds. The difference is tangible, you can feel the difference. Next time you run an extraction, drain the solvent, then wring out the remaining solvent into another pan. The 99% washed plant will be crunchy; whereas, the 'wet' plant will be mushy. It's due to the water which breaks the plant barrier, then lets the alcohol in to ravage the plant.

Washing at Temperature

After alcohol selection, temperature becomes an important factor if you want to avoid waxes. But with the RxCE process using Rapid Winterization, there is no need for cold or frozen washes. But to round out the discussion on washing, these are covered below.

There are three temperature ranges for washing the plant.  

Room Temperature - The most common extraction is done at room temperature guaranteed to extract everything that makes the original unrefined crude oil we've come to know as RSO/FECO.

Cold Temperature - The colder temperature in the kitchen comes from the home freezer which typically runs as low as -20c/-4f. Extraction at this temperature is second best but does not 100% completely freeze waxes allowing some waxes to remain fluid. 

Frozen Temperature - The coldest temperatures possible in the home is using Dry Ice. Dry Ice chills the alcohol below the freezing point of most plant compounds. The goal is to reach at least -40c/-40f. Isopropyl cooled with dry ice can easily reach -55c/-68f with the lowest temperature reaching -62c/-80f. At this temperature, waxes are too cold to dissolve in the alcohol. The alcohol itself will become sludgy at these low temperatures, even more so if water is present; therefore, its crucial to use 99% Isopropyl in this frozen wash. 91% has enough water content to slow down the extraction. Minimal extraction time (i.e., alcohol contact time) for 99% Isopropyl in this frozen environment goes from 20 seconds upwards of 3 minutes.

Plant Material

Choosing the right plant material for extraction is the most crucial decision for clean oil. Here are your three types of plant material, from best to ho-hum. In all cases, the plant material must be extremely dry when performing the wash. 

Procedure

Frozen Wash - Dry Ice is easily purchased in the United States. Hopefully you can source it locally. Isopropyl chilled with Dry Ice can reach temperatures as low as -62c/-80. At temperatures below -40c/-40f, plant waxes are frozen solid and do not easily dissolve. Phospholipids make up the trichome cell walls and must be dissolved in order to access the oils within. Using a Frozen or Cold wash still requires the Silting step to remove the Phospholipids. Here's a simple procedure - 

WARNING: Handling Dry Ice requires wearing protective gear. You must wear thick protective gloves rated for working with dry ice, protective eye wear and full clothing to protect against splashing. 

1. For every liter/quart of alcohol, add 2 lbs dry ice into an large metal pot.

2. Pour in the alcohol. It will rapidly boil at first, but settle into a slow boil once the temperature reaches below -40c/-40f.

3. Place the dry plant material in a Nut Milk Bag and dip it into the frozen alcohol. Use a potato masher to knead the bag like bread dough.

4. Keep kneading the bag for 3 minutes, then lift the bag out of the alcohol and let it drain into the pot for 30 seconds.

5. Place the bag in a second pot. Add more room temperature alcohol to the pot. Save this alcohol as the second wash to make middle shelf oil. 

6. Save any extra dry ice for the Winterize step.

Cold Wash (in the Freezer) - You will need freezer space for both the alcohol and plant material.

1. Place the plant in a closed jar and place both the jar and alcohol containers in the freezer for 12 hours.

2. Pour the cold alcohol into the jar and shake every minute for 10 seconds.

3. After 3 minutes, pour the jar through a Nut Milk Bag to strain out the plant material.  

4. Place the Nut Milk Bag in another pot to let it drain. Save this alcohol in the second pot for a second run to make La Brea.

Room Temp Wash - This is the easiest and fastest way to wash the plant material with alcohol

1. Place the plant material in a jar then pour in the alcohol.

2. Shake the jar for 20 seconds.

3. Pour the contents through a Nut Milk Bag to strain out the plant material.

4. Place the Nut Milk Bag into another pot to let it drain. Save this alcohol in the second pot for a second run to make La Brea.

At this point, you have two containers with the primary wash for your Top Shelf oil and secondary wash for La Brea.

  Science

Isopropyl alcohol is favored here for its unique chemical features. It is available in safe USP-NF and higher grades, is approximately 20% less polar than Ethanol, is faster dissolving oils, and separates from dissolved compounds using salt water, A.K.A., brine. In the next step called Silting performs an amazing feat right before your eyes.  By adding Brine to the Isopropyl, you literally shake the trash out of your oil. The more expensive Ethanol takes longer to dissolve oils and doesn’t allow separation of unwanted compounds as easy as Isopropyl. For this reason, this process highly recommends using 99.9% USP-NF grade Isopropyl for the bulk extraction. 91% Isopropyl works but does introduce water that interferes with the extraction and Silting. 

Cold washing dissolves the desirable cannabinoids quickly and avoids dissolving frozen plant waxes or other plant compounds. Isopropyl is very efficient in dissolving non-polar oils in very short order. Longer soak times allows more unwanted polar plant material to be extracted. Here are the wash times reported by Gray Wolf in his QWISO extraction post:

With a dielectric index of 17.9, versus Ethanol's 24.5, Isopropyl is less polar, yet is still much more aggressive in extracting both targeted and un-targeted elements. Where we start a 3 minute soak with Ethanol, starting point with Isopropyl is 20 seconds.

Like Ethanol, we address it using subzero extraction temperatures, and address the aggressiveness issue by shortening soak time. We typically yield 75 to 80% within 20 to 30 seconds, and pick up the balance using a second soak.

Tips and Tools

==> 1) If using Isopropyl lower than 91%, first Salt-out the Isopropyl. 70% Isopropyl can be raised up to 91% through Salting-Out with table salt.  Add 25% by volume of non-iodine salt to the alcohol, shake, then use a Turkey Baster to draw off the alcohol into a capture jar. Repeat once and you should have near 91% for extractions.

==> 2) Dry Ice washes. Safety first! - USE GLOVES, protective eye wear and full clothing.  Dry Ice can cause rapid frostbite.  Be safe, use the proper gear.  Looking forward, use a metal pot large enough to hold the alcohol, plant and Dry Ice.  Next add the dry ice which makes the room temp Isopropyl boil. Isopropyl will get sludgy below -40c/-40f due to its ice content.  A normal 20 second room temp wash now takes 3 minutes. 

==> 3)  Use Nut Milk Bags to hold your plant material. Nut Milk bags survive the extreme cold temperatures and keep things tidy.  

Trouble Shooting

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