In California, the Bureau of Cannabis Control (BCC) requires that all cannabis products undergo analytical testing before being sold. As a result, cannabis testing has emerged as a booming sub-industry in the world of legal cannabis.

Cannabis testing labs place a great deal of importance on the consistency and accuracy of their testing protocols. However, there’s one overlooked step that can have a big effect on testing results: sample preparation. Let’s look at how cannabis testing labs get your sample ready for analysis.

The Importance of Sample Preparation

When it comes to cannabis testing, a lot of attention is paid to the instrumentation and analytical methods. As a result, sample preparation is often overlooked. But in the end, the quality of the results will depend on the quality of the input. The most cutting-edge analytical instruments won’t make a difference if a sample is prepared poorly.

Selecting a Sample

The first step of sample preparation is sample selection. To be compliant with California state regulations, an employee of the testing lab must collect the sample. The cannabis distributor should be present but cannot help or participate in the sampling process. This eliminates any bias from the distributor to choose the “best” sample for testing. Samples need to be representative of the entire product batch to give the most accurate results.

How much product do you need to provide as a sample? It depends on the type of product and the type of testing. To meet all of the requirements in California, testing labs need to provide the following amounts of product:

Flower Sampling

Sampler must collect 0.35% of total harvest weight per sample

Table A

Unpacked Harvest Batch WeightIncremented SamplesEach Increment Sample Weight (in grams)Total Sample Weight (in grams)
1 – 5 lbs81 gram8 grams
5 – 10 lbs82 grams16 grams
10.01 – 15 lbs161.5 grams24 grams
15 lbs – 20 lbs162 grams32 grams
20.01 – 25 lbs231.74 grams40 grams
25 lbs – 30 lbs232.09 grams48 grams
30.01 lbs – 35 lbs291.94 grams56 grams
35 lbs – 40 lbs292.21 grams64 grams
40.01 lbs – 45 lbs342.12 grams72 grams
45 lbs – 50 lbs342.36 grams80 grams

Cannabis Product Sampling

Cannabis Product Batch Size (units)Number of Increments + Units (per sample)
< 502
51 – 1503
151 – 5005
501 – 1,2008
1,201 – 3,20013
3,201 – 10,00020
10,001 – 35,00032
35,001 – 150,00050

Minimum of 8 grams required to run full compliance test

Note that the numbers might change if the BCC guidelines are updated in the future.

Prepping Cannabis for Testing

After selection, the sample is ready for the lab. The lab technicians are careful to use sterile and aseptic technique. This prevents the sample from becoming contaminated which could result in a false positive during microbial and foreign material screening.

Solid samples like cannabis flower and edibles are ground up, combined with a liquid to dilute and extract the analyte from the sample, and then thoroughly mixed. The effect of this step is two-fold. It exposes as much surface area of the sample as possible while also homogenizing the sample. When the resulting mixture is loaded into an instrument for analysis, it should accurately represent the complete molecular makeup of the original solid sample.


Sample preparation is an often overlooked aspect of the cannabis testing process. However, this step is important for reliable results. At Encore Labs, we’re dedicated to delivering product driven cannabis testing with the highest quality and accuracy to be California compliant. Interested in having your samples tested at our cannabis testing lab in Los Angeles? Contact us today for more information.