EXTRACTION OF CANNABINOIDS FROM BIOMASS

Abstract

A method of extracting at least one cannabinoid from a biomass consisting of industrial hemp comprises: (i) contacting the biomass with a solvent formulation which comprises a C1-4 fluorinated hydrocarbon or a C1-4 hydrofluorocarbon ether, thereby to charge the solvent formulation with an extract from the biomass; and (ii) separating charged solvent formulation from the biomass.

Claims

1. A method of extracting at least one cannabinoid from a biomass, the method comprising the following steps: (i) contacting the biomass with a solvent formulation which comprises a C1-4 fluorinated hydrocarbon or a C1-4 hydrofluorocarbon ether, thereby to charge the solvent formulation with an extract from the biomass; and (ii) separating charged solvent formulation from the biomass.

2. A method according to claim 1, wherein said biomass comprises industrial hemp and/or industrial hemp which has been treated to derivatise one or more cannabinoids included in the hemp and wherein said biomass includes a THC content of less 0.3%.

3. (canceled)

4. A method according to claim 1, wherein said biomass comprises leaves and/or flowers which comprise one or more cannabinoids and/or derivatives of one or more cannabinoids, wherein the sum of the wt % of leaves and flowers in said biomass is at least 98 wt % and wherein said cannabinoid is naturally-occurring in the biomass or is a derivative of a cannabinoid which is naturally-occurring in the biomass.

5. A method according to claim 1, wherein said biomass includes CBD and/or CBDA, wherein a sum (S1) of the wt % of CBD and CBDA in the biomass on a dry matter basis is in the range 0.3 to 4 wt %; and wherein said biomass includes THC and/or THCA, wherein a sum (S2) of the wt % of THC and THCA in the biomass on a dry matter basis is less than 0.3 wt %.

6. (canceled)

7. A method according to claim 5, wherein the sum of sum (S1) and sum (S2) is in the range 0.3 to 4 wt % and/or a ratio defined as the sum (S1) divided by the sum (S2) is in the range 6 to 15.

8. (canceled)

9. A method according to claim 4, wherein in an embodiment (B), said biomass is treated prior to step (i) to derivatise a naturally-occurring cannabinoid in the biomass.

10. A method according to claim 1, wherein the ratio of the wt % of CBD divided by the wt % of CBDA in the biomass is greater than 10.

11. (canceled)

12. (canceled)

13. (canceled)

14. (canceled)

15. (canceled)

16. (canceled)

17. A method according to claim 1, wherein, in step (i), contact of biomass with solvent formulation takes place when the biomass is at a temperature range of less than −5° C. to 20° C.; and wherein the solvent formulation which contacts the biomass is at a temperature range of between 0° c. to 40° C.

18. A method according to claim 1, wherein said solvent formulation comprises the C1-4 fluorinated hydrocarbon which is non-chlorinated.

19. (canceled)

20. A method according to claim 1, wherein said solvent formulation comprises a solvent selected from: iodotrifluoromethane, 1,1,1,2,3,3,3-heptafluoropropane (HFC-227 EA), 1,1,1,2,2,3,3-heptafluoropropane (HFC-227CA) and 1,1,1,2-tetrafluoroethane (HFC-134a).

21. A method according to claim 1, wherein said solvent formulation consists essentially of 1,1,1,2-tetrafluoroethane.

22. (canceled)

23. (canceled)

24. (canceled)

25. A method according to claim 1, wherein the total weight of waxes in the charged solvent and/or an extract derived therefrom is less than the total weight of waxes in the biomass after the biomass has been treated in the method and/or after step (ii).

26. A method according to claim 1, wherein the wax ratio, defined as the total weight of waxes in the biomass after treatment in the method and/or after step (ii) divided by the total weight of waxes in the charged solvent is at least 5.

27. A method according to claim 1, wherein an extract produced after step (ii) after removal of said solvent formulation includes less than 0.5 wt % total waxes.

28. A method according to claim 1, wherein, in the extract and/or charged solvent formulation, the cannabinoid ratio, defined as the total weight of non-wax based cannabinoids divided by the total weight of waxes in the extract is at least 100.

29. A method according to claim 1, wherein an extract produced after step (ii) after removal of said solvent formulation is a mobile oil at 25° C. or a mixture of an oil and an amount of solid or crystalline material.

30. An extract from a biomass wherein said extract includes less than 0.05 wt % of waxes; wherein a cannabinoid ratio, defined as the total weight of non-wax based cannabinoids divided by the total weight of waxes in the extract is at least 5; wherein a ratio (A) defined as (the sum of the weights of CBD and CBDA in the extract):(the weight of terpenes in the extract) is in the range 2:1 to 25:1; wherein a ratio (B) defined as (the sum of the weights of CBD and CBDA in the extract):(the weight of mono and di-terpenes in the extract) is in the range 2:1 to 25:1; wherein a ratio (C) defined as (the sum of the weights of CBD and CBDA in the extract):(the sum of the weights of beta-caryophyllene, humulene, alpha-bisabolol, alpha-pinene, myrcene and limonene in the extract) is in the range 2:1 to 25:1; and wherein said extract includes at least 0.0001 wt % of HFC134a.

31. (canceled)

32. (canceled)

33. (canceled)

34. (canceled)

35. (canceled)

36. (canceled)

37. (canceled)

38. (canceled)

39. (canceled)

40. A method according to claim 2, wherein: said biomass includes a THC content of less than 0.2%; wherein said biomass includes CBD and/or CBDA, wherein a sum (S1) of the wt % of CBD and CBDA in the biomass on a dry matter basis is in the range 1.0 to 3.0 wt %; wherein said biomass includes THC and/or THCA, wherein a sum (S2) of the wt % of THC and THCA in the biomass on a dry matter basis is less than 0.3 wt %; wherein the sum of sum (S1) and sum (S2) is in the range 0.3 to 4 wt %; wherein a ratio defined as the sum (S1) divided by the sum (S2) is in the range 6 to 15.

41. A method according to claim 2, wherein: the ratio of the wt % of CBD divided by the wt % of CBDA in the biomass is greater than 10; said solvent formulation consists essentially of, 1,1,1,2-tetrafluoroethane; a wax ratio, defined as the total weight of waxes in the biomass after treatment in the method and/or after step (ii) divided by the total weight of waxes in the charged solvent, is at least 40; an extract produced after step (ii) after removal of said solvent formulation includes less than 0.05 wt % total waxes; in the extract and/or charged solvent formulation, the cannabinoid ratio, defined as the total weight of non-wax based cannabinoids divided by the total weight of waxes in the extract is at least 100.

42. A method according to claim 40, wherein: the ratio of the wt % of CBD divided by the wt % of CBDA in the biomass is greater than 10; said solvent formulation consists essentially of, 1,1,1,2-tetrafluoroethane; a wax ratio, defined as the total weight of waxes in the biomass after treatment in the method and/or after step (ii) divided by the total weight of waxes in the charged solvent, is at least 40; an extract produced after step (ii) after removal of said solvent formulation includes less than 0.05 wt % total waxes; in the extract and/or charged solvent formulation, the cannabinoid ratio, defined as the total weight of non-wax based cannabinoids divided by the total weight of waxes in the extract is at least 100.

Description

[0120] Specific embodiments of the invention will now be described, by way of example, with reference to the accompanying diagrammatic drawings, in which:

[0121] FIG. 1 is a schematic representation of apparatus for carrying out extraction of a cannabinoid-containing biomass; and

[0122] FIG. 2 is an alternative apparatus for carrying out extraction of a cannabinoid-containing biomass.

[0123] The following materials are referred to hereinafter:

[0124] R134a—refers to 1,1,1,2-tetrafluoroethane.

[0125] Hemp-type L 2.1—a commercially available industrial hemp.

[0126] Hemp-type L 1.7—a commercially available industrial hemp.

[0127] The following abbreviations used herein have the meanings stated.

TABLE-US-00001 Abbreviation Meaning THC tetrahydrocannabinol THCA tetrahydrocannabinolic acid CBD cannabidiol CBDA cannabidiolic acid CBG cannabigerol CBGA cannabigerolic acid CBN cannabinol CBDV cannabidivarin THCV tetrahydrocannabivarin CBC cannabichromene

[0128] Hempflax A hemp—a commercially available industrial hemp, with the following composition:

TABLE-US-00002 Composition Amount (wt %) THC <0.05 CBD 0.148 THCA <0.05 CBDA 0.392 CBGA <0.05 CBG <0.05 CBN <0.05

[0129] Referring to FIG. 1, apparatus 2 for carrying out extraction of a biomass consisting of industrial hemp containing bio-cannabinoids comprises a jacketed stainless steel extraction column 2 having an internal diameter of 3.5 cm and a height of 1 m. Upstream of column 2 is a solvent storage vessel 4 with a liquid metering pump 6 being arranged between vessel 4 and column 2 for circulating liquid within the apparatus in which biomass to be extracted is tightly packed.

[0130] Downstream of column 2 is a collection/evaporation vessel 8 which communicates with the top of column 2 via pipe 10.

[0131] Downstream of vessel 8 is an oil free gas compressor 12 and a monitoring device (not shown) to monitor and analyse fluid flowing downstream of vessel 8. Downstream of the compressor and monitoring device 12 is an in-line heat-exchanger 14 which is arranged to re-liquefy fluid prior to return to vessel 4.

[0132] The apparatus described was used in examples which follow.

Example 1—General Method for Decarboxylating Cannabinoid-Containing Biomass

[0133] Semi-dried leaves and flowering parts of industrial hemp biomass, having water content of ca. 10% or less were selected. A belt dryer (Alco Food type AGT-400/900-E) was used to decarboxylate the cannabinoids present, at a temperature of 110-140° C., biomass bed thickness of between 3-10 mm, a throughput of 500 g/Hr and a treatment time of 1.0-1.5 Hrs.

[0134] Alternative apparatus that may be used for carrying out this step include ribbon blenders, paddle mixers, tumbler type mixers and screw type heat exchangers

Examples 2 and 3

[0135] Following the general method of Example 1, Hemp-types L 2.1 (Example 2) and L 1.7 (Example 3) were decarboxylated and results are provided in the tables below.

Results for Example 2:

[0136]

TABLE-US-00003 Biomass Assay Biomass Assay Con- Pre-decar- Post decar- version boxylation boxylation (%) Total cannabinoids 1.98 wt % 1.95 wt % 98.4 Total CBD(A) 1.93 wt % 1.82 wt % 94.3 CBDA CBD Total THC(A) 0.001 wt % 0.027 wt % THCA THC

Results for Example 3:

[0137]

TABLE-US-00004 Biomass Assay Biomass Assay Con- Pre-decar- Post-decar- version boxylation boxylation (%) Total cannabinoids 1.59 wt % 1.38 wt % 99 Total CBD(A) 1.55 wt % 1.31 wt % 99 CBDA CBD Total THC(A) 0.001 wt % 0.027 wt % THCA THC

[0138] It will be appreciated for Examples 2 and 3 that, in both cases, the amount of THC in the biomass is very low.

[0139] The following examples describe methods and results for extracting a range of samples of industrial hemp under a range of conditions.

Example 4

[0140] A sample of dried (typically containing 1-8 wt % water) industrial fibre hemp (250.2 g) (Hempflax A hemp) with a CBDA content of 0.5 wt % and THCA content of <0.1 wt % was decarboxylated as described in Example 1, milled to powder particle size of 1-2 mm and packed tightly into a stainless steel extraction column having dimensions of 3.5 cm internal diameter and 1 m length and the column was sealed. It was then cooled to −10° C. by placing in a freezer. The equipment was then reassembled, evacuated and storage vessel 4 was charged with HFC134a (approx. 4-6 Kg). Chilled ethylene glycol was circulated through the jackets of the extraction column and the storage vessel, until the temperature of the HFC 134a in the storage vessel reached −5° C. The chilled HFC134a was then percolated through the biomass in column 2 at a flow rate of 3 Kg/hour for fraction 1 extract and for fraction 2 extract, with the flow being directed out of the column 2 and into vessel 8. The HFC134a was continuously evaporated from the vessel 8 using a gas compressor 12 in FIG. 1 and recycled through a condenser 14 in FIG. 1 back into the vessel 4. Extracts were collected in two fractions: part 1 after 1 hour at 0° C. and HFC134a flow rate of 3 Kg/Hr and part 2 collected after a further 6 hours at 25° C. at the same flow rate. In each case, the product was harvested from the evaporation vessel by dissolving in a minimum volume of ethanol. (Note that ethanol was used for harvesting since the vessel in which the product was collected was too large for the small amount of product. There is no need to use ethanol in harvesting when product is produced on a larger and/or industrial scale in an appropriately-sized vessel). Both ethanolic fractions were analysed and results are reported below.

It was found that the CBDA content pre decarboxylation was 1.4 g; and the CBD content post decarboxylation was 1.14 g (appreciating that CBD has a lower molecular weight than CBDA).
Results of analyses are provided in the table below.

TABLE-US-00005 CBD Purity as Weight Content CBD Recovery Sample (g) (g) (wt %) (%) Feed Biomass 250.2 1.14 0.5 — Spent Biomass 249.6 0.2 (i.e. CBD 0.08 12 remaining in spent biomass) Fraction 1 (F1), 2.0 0.6 30 52.6 extracted at 0° C. Fraction 2 (F2), 1.9 0.3 18.1 26.3 extracted at 25° C. Fraction F1 + 3.9 0.9 79.9 Fraction F2
Total yield=79.9%
Total mass balance=91.9%

[0141] It is noted that, in the experiments, the ethanol referred to is used as a diluent for HPLC analysis used and is accounted for in the calculations.

[0142] Thus, it should be appreciated from the example that the process can be used to produce a high CBD yield since, in the combined extracts, the total yield of CBD was 79.9 wt %. The product produced was a honey-coloured, mobile viscous oil with a rich aroma typical of a presence of terpenes.

Example 5

[0143] The procedure described in Example 4 was generally followed on an industrial hemp sample which had been decarboxylated as described in Example 1. Six fractions were collected at 11-minute intervals using the same flow rate and temperature.

[0144] Results are provided in the table below which includes analysis of cannabidiol (CBD), tetrahydrocannabinol (THC) and cannabigerol (CBG) contents.

TABLE-US-00006 CBD CBD Cumulative Cumulative Weight Content CBG THC Weight CBD Weight Recovery Sample ID (g) (% wt) (% wt) (% wt) (g) (g) (%) Biomass 290 0.356 <0.1  <0.1  1.03 Spent biomass 287 0.12 — — 0.35 33.9 Fraction F1 0.38 38.7 — 0.60 0.15 0.15 Fraction F2 0.28 35.0 — 0.80 0.10 0.25 Fraction F3 0.48 26.5 1.75 0.74 0.13 0.38 Fraction F4 0.38 21.8 1.84 0.53 0.08 0.46 Fraction F5 0.48 16.5 2.10 0.35 0.08 0.54 Fraction F6 0.50 13.0 2.05 0.21 0.07 0.61 59.2
CBD Extraction yield=59.2 wt %
Average THC content=0.47 wt %
Mass Balance=93.1 wt % (which is a good result considering physical losses are inevitable at the scale used).

[0145] It should be noted that the extracts are relatively concentrated in CBD and include a relatively low amount of THC. Typically, in use, the target CBD concentration might be around 2 wt %, resulting in a very low concentration of associated THC.

Example 6

[0146] The procedure described in Example 5 was followed on another industrial hemp sample.
Results are provided in the table below.

TABLE-US-00007 Cumulative CBD CBD CBD Cumulative Weight assay Weight Weight Recovery Sample ID (g) (% wt) (g) (g) (%) Biomass 302 0.339 1.025 Spent 300 Not biomass available Fraction F1 1.10 46.90 0.51 0.51 49.8 Fraction F2 0.50 37.50 0.19 0.70 68.3 Fraction F3 0.34 23.40 0.08 0.78 76.1 Fraction F4 0.20 19.90 0.04 0.82 80.0 Fraction F5 0.14 17.40 0.02 0.824 80.4
Total CBD extraction yield=80.4 wt %
Average THC content=0.25 wt %

[0147] Again, the process is found to produce a high CBD yield. The product was a honey-coloured, mobile oil, having an aroma typically of a terpene content.

Example 7

[0148] The procedure generally described in Example 5 was followed using Hemp-type L 1.7. Results are provided in the tables below.

TABLE-US-00008 Weight CBDA CBG CBD THC CBC Sample ID (g) (% wt) (% wt) (% wt) (% wt) (% wt) Biomass 561.0 0.017 0.002 1.272 0.023 0.066 Spent biomass 539.0 0.14 Fraction F1 7.50 0.15 46.5 0.1 1.7 Fraction F2 5.60 0.18 31.0 1.1 2.16 Fraction F3 3.90 0.02 0.25 18.0 0.84 2.0 Fraction F4 6.00 0.02 0.22 15.0 0.56 1.04

TABLE-US-00009 CBD Cumulative Cumulative Assay Weight CBD recovery (% wt) (g) Weight (g) (%) Fraction F1 46.5 3.450 3.45 48.3 Fraction F2 31.0 1.73 5.18 72.5 Fraction F3 18.0 0.70 5.88 82.3 Fraction F4 15.0 0.90 6.78 95.0
CBD Extraction yield=95.0 wt %. Note, this is a particularly high yield.

Example 8

[0149] The procedure of Example 5 was followed using Hemp-type L 2.1. Results are provided in the tables below.

TABLE-US-00010 CBD CBD Cumulative Cumulative Weight Assay Weight CBD Recovery Sample (g) (% wt) (g) Weight (g) (%) Biomass 476.0 1.90 9.05 Spent biomass 464.0 0.42 1.95 21.6 Fraction F1 7.20 53.5 3.85 3.85 42.6 Fraction F2 2.60 44.1 1.15 5.0 55.2 Fraction F3 1.30 37.7 0.50 5.5 60.8 Fraction F4 1.20 32.1 0.40 5.9 65.2 Fraction F5 0.80 28.5 0.23 6.1 67.4

TABLE-US-00011 Total CBD CBDa THC THCa CBC CBG cannabinoids Recovery 66%  1%  89% n/a 73% 57% 65% Mass 87% 111% 110% n/a 96% 74% 88% balance

Example 9

[0150] The procedure of Example 5 was followed using Hemp-type L 1.7. Results are provided in the tables below.

TABLE-US-00012 Cumulative CBD CBD CBD Cumulative Weight Assay Weight Weight Recovery Sample (g) (% wt) (g) (g) (%) Biomass 505.0 1.22 6.14 Spent 480.0 Not biomass available Fraction F1 7.90 45.39 3.59 3.59 58.4% Fraction F2 4.00 25.87 1.04 4.63 75.4% Fraction F3 2.80 15.06 0.42 5.05 82.2% Fraction F4 3.70 8.46 0.3 5.35 86.3% Fraction F5 3.00 6.10 0.2 5.55 90.4%

TABLE-US-00013 CBDA CBG CBD THC CBC Sample ID (% wt) (% wt) (% wt) (% wt) (% wt) Biomass nd 1.22 0.02 0.07 Spent biomass — — — — Fraction F1 <0.1 0.18 45.4 1.1 1.90 Fraction F2 <0.1 0.24 25.87 1.05 2.42 Fraction F3 0.28 15.06 0.70 1.96 Fraction F4 0.29 8.46 0.37 1.13 Fraction F5 0.27 6.10 0.26 0.72
CBD extraction Recovery=90.4 wt %
Total cannabinoids recovery=92 wt %

Examples 10 and 11

[0151] The following example refer to duplicate experiments (Expt. 1 and Expt. 2) carried out on two hemp types as shown (referred to as Examples 10 and 11). The experiments were carried out quantitatively in order to assess content of terpenes present in the extracted products. The extracts were collected in fractions but not all fractions were fully analysed.

Biomass Type: L 2.1 (Example 10) Decarboxylated

[0152]

TABLE-US-00014 Expt 2 Expt 1 (% in Selected (% in extract) extract) component Fraction 1 Fraction 2 Fraction 1 B-caryophyllene 2.73 0.94 2.94 Humulene 0.76 negligible 0.34 α-Bisabolol 3.0 — 0.34 Limomene 0.81 — 0.37 Total terpenes % 7.3 0.94 4.0  CBD % 41.51 55.2 44.7

Biomass Type: L 1.7 (Example 11) Non-Decarboxylated

[0153]

TABLE-US-00015 Expt 1 Expt 2 Selected Fraction1 Fraction1 component (% in extract) (% in extract) B-caryophyllene 13.61 15.42 Humulene 4.23 4.77 α-Bisabolol 0.3 0.36 Limomene 1.22 0.13 Total terpenes % 19.36 20.68 CBDA % 11.1 13.3
In both examples 10 and 11 it was estimated that substantially the total amount of terpenes in the biomass was extracted in the process. The extracts described can be used in preparation of dietary ingredients, dietary supplements and/or health supplements.

[0154] As an alternative to use of the apparatus of FIG. 1, the apparatus described in FIG. 2 may be used.

[0155] Referring to FIG. 2, apparatus for carrying out fractional extraction using a liquefied gas as extraction medium comprises an extraction column 102 in which material to be extracted is tightly packed. The column may be jacketed and include heating/cooling means for temperature control. Upstream of the column 102 is a hold vessel 104 for containing the liquefied gas, for example HFC 134a. The vessel 104 is connected downstream, by pipework 106, to the upper end of the column 102 for transferring the extraction medium into the column 102. A liquid metering pump 108 is provided in pipework 106 for controlling the flow of extraction solvent to the column. Immediately upstream of the column, the pipework includes an in-line heat exchanger 110 arranged to heat (or cool) liquid prior to its passage into the column. Between the pump 108 and heat-exchanger 110, there is a modifier solvent supply pipe 112 which is arranged to deliver a modifier solvent from a storage vessel 114 into the pipework 106 so that it mixes with liquefied gas from vessel 104. A liquid metering pump 116 in supply pipe 112 controls the flow of liquid within the pipe 112.

[0156] Downstream of the vessel 102 are shown three collection/evaporation vessels 120, 122, 124 although more such vessels would generally be provided for collecting more than three different aliquots. Each of the vessels 120, 122, 124 includes an inlet pipe 126 and an outlet pipe 128 each having associated control valves 130. The vessels 120, 122, 124 are arranged to communicate with column 102 via pipeline 132 which is connected to the bottom of the column. A monitoring device 134 is arranged to monitor and/or analyse fluid flowing in pipeline 132. Downstream of pipeline 132 is a pipeline 136 which communicates with vessel 104 and includes an associated gas compressor 138 for liquefying gas prior to its passage back into the vessel 104.

[0157] The apparatus further includes any necessary in-line filters, one-way valves, flow control valves, pressure regulators and pressure release valves and instrumentation for reading temperature, pressure and pH to allow appropriate process control and safe operation of the apparatus.

[0158] In use, a vacuum pump (not shown) is operated to remove air from the apparatus after the material to be extracted has been packed into the column 102. Liquefied gas is then charged to the vessel 104 and co-solvent, if this is used, is charged into vessel 114. With any heating/cooling means of the apparatus appropriately set, liquid is passed from vessel 104 to the column 102. The liquid slowly percolates through the material in the column and extracts compounds from the material as it does so. Initially, the most soluble compounds included in the biomass are extracted preferentially and these are entrained with liquid as it passes from the column into pipeline 132. The liquid (and entrained extract) is then directed into vessel 120 by opening the appropriate valve. After a period of time which may be determined in dependent upon an output from monitoring device 134, subsequent liquid passing out of the column is directed into vessel 122. Subsequently, it is directed into vessel 124 and later to other vessels (if provided). Thus separate aliquots are collected in vessels 120, 122, 124 and the constitution of the extracts therein should differ, with compounds or compositions which are most soluble in liquid passing through the column being more concentrated in the vessels which initially are used for collection and less soluble compounds or compositions being more concentrated in collection vessels used later in the process.

[0159] The constitution of extracts may also be affected by delivering a co-solvent from vessel 114 into pipeline 108 and mixing the co-solvent with liquid from vessel 104. The combined extraction solvent may then be adapted to extract preferentially certain compounds or compositions. The co-solvent may be delivered as described herein for manipulating the extraction of the biomass. Additionally and/or alternatively, the heat-exchanger 10 may be used to adjust the temperature of the extraction solvent thereby to control the nature of compounds or compositions preferentially extracted. Also, the temperature of the column itself (and thereby the biomass therein) may be adjusted as another means of affecting the nature of extracts.

[0160] After the extraction of the biomass has been completed (or prior to completion whilst extraction in the column 102 is ongoing), the control valve to outlet pipe 128 of vessel 120 may be opened and compressor 138 operated to remove liquefied solvent from the vessel 120 and return it to vessel 104, leaving the compound(s)/composition(s) in vessel 20. This process may be repeated to isolate the different extracts in the respective vessels 120, 122, 124.

[0161] The aforementioned examples involve treatment of a cannabinoid-containing biomass which has been decarboxylated (as is conventional in industry) as described in Example 1. However, in some cases, it is found that such decarboxylation can result in charring of the plant material, a darkening in its colour and production of acrid smoke. This may also result in loss of cannabinoid content and production of lower purity extract. Example 8 which follows describes treatment of biomass prior to any decarboxylation.

[0162] The invention is not restricted to the details of the foregoing embodiment(s). The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.