How to Test The Quality of Your Hash

Viviane Schute        

Cannabis enthusiast and student of the art of solventless extraction


Ice water extraction is the gold standard for making the best hash, a process that lets hash makers collect the trichome heads of the cannabis plant and leave all other plant material behind. Anything besides resin heads is considered contamination, which would include trichome stalks, minuscule plant particles, chlorophyll, and foreign objects like dirt or insect parts.  

Trichome heads contain the highest concentrations of the most desirable therapeutic compounds that cannabis produces, which is what makes them so very valuable to solventless extraction artists. These heads are often referred to collectively as resin, the top prize for hash makers. 

The more pure the hash, the higher the quality. So what is considered pure? Bubble hash that’s all resin and no plant material is as pure as it gets. This top-notch hash is called a 6-star hash. The rating system goes from 1 all the way to 6, with 6 being the pinnacle. 

Read more in our article How Bubble Hash Is Rated.

How can you test the quality of your hash? There are a few different techniques you can use to gauge the purity of your bubble hash. The best approach is to try a combination of these methods. 

Let's look at them one by one. 

1. Hand Press Technique

This is also known as pressing a flag, which is a way to spread the hash into a very thin patty between two layers of parchment paper. Very high quality hash will press incredibly easily, just with some light pressure and the heat between your fingers. If the hash easily presses into a flat patty between two sections of parchment paper, that means it has very high oil content, which is what we’re looking for. 



You can also place the hash inside a folded piece of parchment paper and put The Press Club Rosin Stamp on top, allowing the rosin stamp weight to weigh down the hash naturally. If the hash presses down into a thin patty under the weight of the rosin stamp, this is a very positive sign. Best case scenario is that the sandy-textured loose resin becomes a flag, a super thin strip of hash.

2. Dab It and Check for Residue

Sometimes this is the final test you’ll do, but it’s also the most telling. So let’s take a look at it now. Dabbing temp depends on personal preference, but 500F is a solid choice. This temp allows us to see the true quality of the hash without burning the purity of it. If you’re able to take a dab at this temp and there’s no residue left behind, then congratulations, you’re working with a true 6-star hash! Any residue left means it’s not true full melt hash, it’s maybe a 5 or 4-star. If there’s a lot of black or brown residue, you’re not working with a high-quality hash.

3. Lighter Test 

Use a lighter to hold a flame to your hash and watch what happens. Is it burning, or simply bubbling and melting? If it’s burning, that’s a bad sign, as it signifies plant matter in the hash. If it melts instead of burns, that means there is very high oil content in the hash, which is a positive attribute. Pure hash takes much longer to ignite, since the oil takes longer to heat up and burn.

4. Simple Visual Inspection 


For this technique, all you need is your hash and a magnifying glass. If you don’t have a magnifying glass, no problem, just use your phone’s camera. Inspect the hash for particulates like black specs. If little specs are present, that’s a bad sign. Also look for tiny pieces of green plant matter, or an overall green tint to the hash. Green indicates chlorophyll, which is a common contaminant in hash. If there’s no black specs or green coloring, that’s a great sign.


5. How’s the nose? 

Finally, just smell the hash and let the terpenes speak for themselves. Do you smell an explosion of fruit, gas, pine, and/or citrus? Great hash will be packed with terpenes, the compounds that cannabis naturally creates, which are responsible for its unique smell. High-quality hash maintains most of the terpenes which are present in the living plant, and these are evident when you smell the hash. Let your nose be your guide!


To assess the quality of your hash various methods can be used to determine its purity and overall excellence. One effective approach is the Hand Press Technique, also known as pressing a flag. This method involves flattening the hash into a patty, between layers of parchment paper. High quality hash will easily flatten with pressure and warmth from your fingers indicating an oil content. Alternatively using The Press Club Rosin Stamp can naturally compress the hash into a patty showcasing its quality if it forms a flag-like shape.

Another method involves heating the hash at 500°F and checking for any residue left behind. Genuine 6-star hash will not leave any residue while lower quality hash may leave some behind. The Lighter Test includes applying flame to the hash to observe if it burns (suggesting impurities) or melts (indicating oil content). Inspection using a magnifying glass or phone camera can help identify particles such as specks or green plant material, which are signs of contamination. Lastly, assessing the aroma can help detect terpenes, in high quality hash. By combining these techniques you can obtain an evaluation of the purity and quality of your hash.

Thoughts? Let us know by joining our secret Facebook group. Hang out with a community of like-minded solventless heads like yourself. Ask our head extractor questions, share your latest press and learn from hobbyists and experts in the industry.


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