Introduction

CBD Hash, also known as cannabidiol hashish, is a hemp-derived product rich in CBD and low in THC. In Switzerland, legislation permits the distribution of certain hemp-based products as long as their THC content does not exceed 1% (according to the Narcotics Act, RS 812.121). This regulation, unique to the Confederation, has allowed the emergence of a legal market for CBD products, including various forms of hash made from hemp resin.

One key quality criterion for hash is its particle size, which refers to the microscopic scale of the particles. It is sometimes said that sieving at less than 160 µm results in a purer and more homogeneous product. But what is the reality, and where does this 160 µm figure come from? This article aims to clarify the role of particle size in the purity of CBD Hash, based on verified data and Swiss legislation.

What is Particle Size?

Particle size is the measurement of the size of particles in a given material. In the context of hemp and hash, it involves measuring the diameter of resin glands, plant fragments, and any other solid components resulting from the extraction or sieving process. Several tools can assess this particle size:

• Standardized sieves: These have meshes of different sizes (100 µm, 160 µm, 200 µm, etc.).
• More sophisticated instruments: Laser analyzers or electron microscopy.

In the production of CBD Hash, much of the technique relies on separating the resin (which contains cannabinoids, terpenes, and other active molecules) from the raw plant materials (leaves, stems, chlorophyll). Reducing the size of the particles in the final product theoretically increases the proportion of resin relative to the rest of the dry matter.

Standard Particle Size in Traditional Hashish

In traditional hashish, sieving is often done using more or less tight fabrics (e.g., 180 µm, 150 µm, 120 µm…) to separate the resin glands from coarser particles. Producers adjust the mesh according to the type of hemp used, the maturity stage of the plant, and the desired outcome of the final product. Generally, resin glands (trichomes) are mostly between 70 µm and 150 µm, although this can vary by variety (Scrivens, A. (2021). Analysis of Cannabis and Hemp: Understanding Potency and Purity. Journal of Cannabis Research, 3(22)).

Why 160 µm?

The diameter of 160 µm is often cited as a sieving reference because it is above the majority of fully formed trichomes (around 120 µm to 140 µm) and below larger plant fragments. In other words, being able to filter particles larger than 160 µm allows for the removal of a significant portion of plant contaminants while retaining most of the resin glands.

Understanding the Size Range of Trichomes

Trichomes, these small outgrowths on the surface of the hemp flower, are rich in cannabinoids (such as CBD and THC) and terpenes (responsible for aromas). Studies show that capitate glandular trichomes can vary between 50 µm and 150 µm depending on the variety and maturity of the plant (ZHAW, 2021, “Analytical Testing of Hemp: Pesticide, Heavy Metal, and Cannabinoid Profiles”). Applying a 160 µm mesh thus aims to capture the bulk of this resinous material while limiting the intake of dust and small plant matter.

Legal Framework in Switzerland: Essential Reminder

In Switzerland, the legislation around hemp and derived products is based on the principle of a THC content less than or equal to 1% for so-called “legal” cannabis varieties (Ordinance on the Control of Narcotics, 812.121.21). CBD-rich products can circulate in the market, whether in the form of flowers, oils, creams, or resin (hash). However, certain elements must be considered:

1. Product traceability: CBD Hash producers must be able to justify the variety of hemp used, ensure pesticide control, and guarantee a THC level below the legal limit.
2. Consumer safety: Laboratory analyses are required to check for the presence of heavy metals, residual solvents (in the case of chemically extracted Hash), and microbiological contaminants.
3. Labeling: It must clearly indicate the CBD and THC content and comply with legal marketing standards.

Regarding particle size, no legal provision in Swiss regulations explicitly imposes a maximum or minimum particle size for CBD Hash. However, analysis laboratories and producers rely on internal quality standards, often inherited from the traditional sieving of hashish, adapted to the Swiss market reality and validated by laboratory analyses.

Impact of Particle Size on Purity

1. Reduction of Undesirable Plant Materials

The finer the production sieve, the fewer fragments of leaves, stems, or undesirable elements are found in the final product. For a CBD Hash with a sieve mesh of 160 µm or less, the concentration of cannabinoids can be higher than in hash produced with a larger mesh. The presence of larger particles often ends up diluting the proportion of active resin.

2. Better Control of External Contaminants

Sieving at 160 µm acts as a filter to capture certain non-resinous impurities:

• External pollens.
• Insect debris.
• High dust levels.

However, it is important to note that this control does not necessarily prevent chemical residues such as pesticides or solvents. Only laboratory analyses can confirm the absence of chemical contaminants. But fine sieving can help reduce any solid micro-particles present.

3. Increase in Cannabinoid Content

By more finely separating the resin glands from the rest of the material, the relative share of cannabinoids and terpenes can be increased. This results in a potentially more concentrated final product in CBD, thus more appealing to users seeking a relaxing effect, without a pronounced psychoactive effect (as THC remains low). Several Swiss laboratories specializing in cannabinoid analysis have confirmed that, for the same hemp variety, finer sieving often results in a higher CBD level (Scrivens, 2021).

4. Homogeneity and General Appearance

From 160 µm or less, the appearance of Hash tends to be more “powdery,” homogeneous, and malleable. Consumers often notice a more uniform texture, easier to crumble. This can be sought for vaporized consumption or for mixing in culinary preparations.

Production Methods and Particle Size

Several techniques are used to produce CBD Hash. They directly influence particle size:

1. Dry Sift Sieving
   The most traditional method involves collecting resin by shaking or rubbing dried and frozen hemp flowers over a sieve. By repeating the operation several times with different sieves, the particle size is gradually refined to extract increasingly fine and resinous particles.

2. Water Extraction (Ice-O-Lator)
   The flowers are placed in ice water and gently stirred. The heavier trichomes detach and sink to the bottom of the filtration bags. Each bag has a specific mesh (often 220 µm, 160 µm, 120 µm, 70 µm) to collect different qualities of resin. In the end, the extracted hash is dried before being refined.

3. Solvent Extraction
   Some producers use solvents (ethanol, butane, supercritical CO₂) to dissolve the resin. Once the solvent is evaporated under controlled conditions, a concentrate of cannabinoids and terpenes remains. The particle size then depends on purification and the filters used during the extraction process. Often, the raw product can be transformed into hashish, then possibly re-sieved for a less sticky appearance.

Laboratory Control and Validation

Once the process is complete, most recognized Swiss producers call on a specialized laboratory to measure:

• The CBD and THC levels (chromatography method), in accordance with Swiss law (THC < 1%).
• Solvent residues, if there was chemical extraction (e.g., butane, ethanol).
• Pesticides and heavy metals (list of authorized or prohibited substances, according to the current Federal Ordinance).
• The terpene profile, often of interest to characterize the product’s smell and taste.

Laboratories such as those at the University of Geneva or the Zürcher Hochschule für Angewandte Wissenschaften (ZHAW) offer these services reliably, relying on validated methods (ZHAW, 2021).

Realism of Marketing Promises

It happens that some sellers or distributors highlight the particle size of hash as a guarantee of absolute purity. Claiming that sieving at less than 160 µm guarantees 100% absence of contaminants is inaccurate. The control of chemical or microbiological contaminants cannot be done solely by particle size. Moreover, the exact CBD ratio in hash largely depends on the hemp variety used in the first place.

Purity claims should therefore be read with a critical mind. In practice, finely sieved hash is likely to contain a higher concentration of cannabinoids, but only a laboratory test can provide a quantified and precise result. Studies on the correlation between particle size and hash purity suggest a noticeable improvement in the resin/plant material ratio (Scrivens, 2021), but not an absolute qualitative leap if the raw material is of lower quality or contaminated from the start.

Recommendations for Consumers

1. Inquire About the Product’s Origin

The first reflex before purchasing CBD Hash is to check the reputation of the producer and distributor. In Switzerland, serious brands generally offer:

• A laboratory analysis sheet (with test date and laboratory name).
• Clear labeling specifying the hemp variety and cannabinoid levels.

2. Prefer Hash from Suitable Sieving

Although 160 µm is a frequently cited reference, other sieve sizes can produce excellent results (120 µm, 180 µm, etc.). The main thing is that the producer has followed a rigorous protocol and conducted quality tests.

3. Check the THC Level

Even below the legal threshold of 1% in Switzerland, slight variations can exist, ranging from 0.4% to 1%. To avoid any risk (especially for drivers or those subject to strict screening tests), it is better to choose CBD Hash with a THC level much lower than the legal threshold. Thus, the psychoactive effect remains low or even nonexistent.

4. Control for Possible Additives

Ensure that no additives or artificial flavors have been added to alter the taste, texture, or color of the hash. Serious producers generally indicate the exact list of ingredients or any added oils. “Full Spectrum” products guarantee the natural presence of all available cannabinoids and terpenes in the plant, without resorting to external substances.

Preservation of Fine Particle Size Hash

Once you have acquired CBD Hash with a particle size below 160 µm, it is essential to take care of it to preserve its quality. Indeed, a finer product tends to be more sensitive to humidity and oxidation:

• Store it in an airtight container, away from light and air.
• Prefer a low humidity level (around 55% to 62%) to avoid mold formation or terpene degradation.
• Avoid high temperatures (above 25 °C) that accelerate oxidation.

Proper packaging extends the life of the Hash and preserves its aromas, consistency, and CBD concentration.

Suitable Consumption Methods

With a very fine particle size, CBD Hash lends itself to several consumption methods:

1. Vaporization
   More and more enthusiasts use vaporizers suitable for concentrates. A fine particle size facilitates homogeneity during heating. This results in aromatic vapor rich in cannabinoids, according to studies on legal cannabis consumption methods in Switzerland (see Swiss Federal Office of Public Health, risk reduction guide, 2020).

2. Hot Inhalation
   Some consumers seek the traditional experience by combining CBD Hash with tobacco or smoking herbs (e.g., damiana). However, this approach is less healthy and releases carcinogenic substances related to combustion. Swiss authorities recommend caution and encourage limiting tobacco smoke (OFSP: Health Recommendations, 2021).

3. Infusion or Incorporation into Food
   Once decarboxylated (heated at low temperature, about 100 to 120 °C for 30 to 45 minutes), Hash can be mixed with fats (butter, oil) for culinary use. The fine particle size allows for a more homogeneous mixture, facilitating CBD dosing and improving the consistency of the preparation.

Scientific Studies on Particle Size and Purity

Although specific research on the direct link between particle size < 160 µm and CBD Hash purity is limited, several scientific studies address the importance of sieving and trichome isolation to obtain more concentrated extracts:

• Scrivens, A. (2021). Analysis of Cannabis and Hemp: Understanding Potency and Purity. Journal of Cannabis Research, 3(22). This research highlights the impact of particle separation in determining cannabinoid levels.
• ZHAW (2021). Analytical Testing of Hemp: Pesticide, Heavy Metal, and Cannabinoid Profiles. Department of Life Sciences and Facility Management. This report presents laboratory methods for analyzing the chemical profiles of hemp extracts, emphasizing the importance of particle size in sampling protocols.

The conclusions of these works suggest that if the raw material is of quality, passing through meshes of 160 µm or less generally results in a product richer in resin, and thus richer in CBD.

Future Perspectives

The world of CBD Hash is constantly evolving, with the emergence of new extraction and purification technologies. Notably, developments include:

• Micro-filtration: Use of even finer filters (50 µm, even 25 µm) for highly targeted extractions.
• Rosin Technique: Hot pressing of the flower or hash to extract an even more concentrated resin.
• Advanced Chromatography: Allowing the separation of certain cannabinoids and terpenes to create custom profiles.

However, regardless of the method, Swiss legislation remains strict on the allowed THC level (max. 1%). Future innovations must always respect this legal framework so that products can be marketed transparently.

Conclusion

Particle size plays a crucial role in the purity of CBD Hash, as it determines the proportion of resin (rich in cannabinoids and terpenes) relative to plant material. The 160 µm threshold is often mentioned because it corresponds to the average size of the most interesting resin glands. Below this mesh, a significant portion of coarse particles that can alter taste quality and reduce CBD content is generally removed.

However, the importance of this single measure should not be overestimated. A multitude of factors come into play: the hemp variety, growing conditions, extraction method, and laboratory quality control. In Switzerland, thanks to a relatively clear legal framework (THC < 1%) and the expertise of recognized laboratories, it is possible to find high-end CBD Hash, whose production and sale are strictly regulated.

For the consumer, it remains essential to prioritize hash with clearly documented traceability and laboratory analyses. This ensures not only a low THC content but also a product free of contaminants and presenting the desired CBD level. Particle size < 160 µm is an interesting indicator, but it must always be accompanied by analytical evidence to guarantee pure, safe, and legally compliant CBD Hash.