With the new and expanding demand for professional quality botanical extracts, oils and concentrates, there are various principles to take into account regarding the clarification process to ensure the consistent production of the highest quality products.
As leaders in the filtration of precious liquids for over 40 years, Scott Laboratories is a valuable and experienced resource for filtration media and equipment in North America.
The filtration and clarification step is crucial in safeguarding product quality. This market demands a bright product without a presence of visual turbidity that may originate from plant material, impurities and colloidal material like lipids. Color is another important quality parameter. A golden hue might be acceptable whereas a dark, mud-like concoction is not. Clarity, color and flavor are attainable through conscientious clarification and purification steps.
The cleaner and more efficient the extraction process is, the less you would need to filter.
Crude extraction is a process that makes use of a solvent like CO2, Butane, Propane or Ethanol to extract the desired product. Different applications and laws influence the choice of solvents.
Extractions using cold ethanol are used to produce distillate oils which can be used for vaping applications for example. Ethanol is also used in manufacturing environments where the use of volatile solvents like propane and butane are prohibited. It is also the most commonly used solvent and the one we deal with the most during technical calls with customers.
CO2 provides the cleanest extraction but takes the longest to extract. The type of equipment needed in this case demands high capital costs and operates under very high pressures. Winterization is not necessary when extracting with cold ethanol because the temperatures are low enough already.
When extracting with CO2, butane or propane, winterization or freezing is necessary for solvent removal. Winterization involves dropping temperatures to between -40°F and -100°F for 12-16 hours. The winterizing process freezes the lipids, fats and other associated colloids in the product and helps to separate them from the desirable elements. After freezing, the product should be filtered immediately through a cellulose depth filter to remove particulate and other colloids that have come out of solution. Multiple filtration steps can also be taken by placing a carbon impregnated media like the Seitz Supradisc AKS4 lenticular module after this first depth filter to remove color (extracted chlorophyll) and unwanted flavor like terpenes and esters.
Filtration not only clarifies the product but removes unwanted particles that can interfere with the potency of some of the desirable complexes in botanical extracts.
It’s important not to expose the extract to extended periods of light or oxygen which can also lead to the accelerated degradation of these complexes. A closed system like a lenticular housing is very popular for this reason as it has a compact footprint and can be purged with gas to get rid of residual product. There is also no drip loss as you sometimes find with sheet filter presses. The media is reusable and storable between uses.
Running the extract through an initial polish to retain some of the plant material that might make it past the extraction process will make subsequent steps more efficient. We prefer to use a bag filter housing, for this reason, loaded with felt propylene bags in a 5 micron pore size. If you have a lot more plant material you can use a coarser porosity bag but it is a good idea to review the extraction process and refine that first before diving into filtration.
As the second filter in this chain, we recommend a lenticular filter loaded with filter media containing cellulose and filter aids like diatomaceous earth (DE) and perlite to ensure a bright polish.
This bright polish sets the product up perfectly for filtering through activated carbon as the final purification step.
Chlorophyll and other pigmentation in the raw extract contributes to the green and dark brown appearance or a raw extract. These pigments as well as waxes cause premature breakdown of the desirable complexes in the botanical extracts and can lead to an increase in quality variation between batches.
Filtration through an activated carbon impregnated media such as the Seitz AKS4 will remove these impurities and lead to a more stable, professional quality extract.