Pressing Rosin with Vacuum Bag Tek


Todde Philips

🇺🇸 Retired veteran, father, rock-climbing expert & rosin connoisseur.

Nowhere else in cannabis can you find the rapid pace of innovation that exists in the world of solventless extraction. It’s truly awesome to see so many new techniques, or teks, coming to light, thanks to the dedicated work and experimentation of hash and rosin makers. A great example of this type of innovation is Vacuum Bag Tek. 

Vacuum Bag Tek is a way to remove air pockets from loose resin that’s packed inside rosin bags prior to pressing. Reducing the air inside rosin bags before extraction leads to meaningful benefits in the final product. 

Benefits of Vacuum Bag Tek for Pressing Rosin

Quality is always the number one pursuit, and vacuum bag tek offers clear value in this respect. Reducing air pockets within loose resin leads to a crystal clear product, assuming the resin is crystal clear to begin with. Clarity is a meaningful benchmark of quality, and clearer rosin is generally seen as higher quality. 

Another advantage of vacuum bag tek involves efficiency. Reducing air in rosin bags reduces the risk of blowouts when pressing large volumes of hash. It’s not unusual to yield 4 ounces of rosin in a single press with this technique. Yielding more rosin per press saves time and also reduces the quantity of rosin bags used over time. These little wins add up in the lab. 

Finally, vacuum-sealing is a good substitute for the pre-press, allowing extractors to skip that separate step of pre-pressing the hash with a press. A vacuum seal will automatically compact the loose resin inside the bag, priming it for extraction on the press. 

Equipment for Vacuum Bag Tek



How To Vacuum Bag Tek

1. Prepare the Hash
Starting with dry hash is absolutely necessary. Wet hash can leave traces of moisture in the rosin, which can harbor mold once it’s sealed in jars. While air drying loose resin is a legitimate approach, freeze drying is ideal. 


After the hash comes out of the freeze dryer, use a metal collection card to chop up the resin to break apart the large chunks that form. You can do this directly on the drying trays.

Sieving the hash through a metal strainer can also do the job, but this often disperses tiny resin particles into the air, wasting the valuable material. The metal strainer will also undoubtedly capture and hold some of the resin. 

The goal is to achieve a sand-like consistency with the hash. 

2. Pack the Rosin Bags
Now it’s time to fill the rosin bags with the completely dried and granular loose resin. In this example, we’re using two 25-micron bags and one 160 micron bag, size 2.5” x 4.5”. Using three bags has several benefits, including enhanced structural support to prevent blowouts, optimized filtration, and reduced chance of slippage between the plates during extraction. 

Read more about loading rosin bags and using the triple bagging method in our article How To Pack Rosin Bags.

Use a funnel to fill one of the 25-micron bags with 35-45g of loose resin, which should make the bag about ¾ to ⅘ of the way full. This is a good estimate, but the key is to ensure there’s enough empty space after filling at the top of the bag to sufficiently fold over. You can fill the bags with as much hash as you can, while still allowing enough of a gap at the top to fully fold the bag over itself to seal the hash inside. More on that in a minute. 

If you’re working with enough hash to fill multiple bags, be sure to weigh out the hash and fill each bag with the exact same amount. This ensures consistency across all bags during extraction. 




3. Layer and Close the Rosin Bags
Hold the top of the rosin bag and give it a little shake, allowing the resin to settle all the way into the bottom of the bag and compact on itself a bit. It also gives you enough room at the top of the bag to fold over. 

Fold the top of the bag over, then place the folded end of the bag into the other 25-micron bag. Keep the seams aligned on the length of both bags. Then, seal the top of this second bag. 

Finally, take that double-bagged hash and place it into the 160-micron bag. Fold the top of that bag, sealing everything nice and tight inside. 

Read more about properly using three rosin bags in our article Tips to Minimize Filter Bag Slippage Hydroplaning.

4. Vacuum Seal the Rosin Bags
After all the hash pillows are triple-bagged and fully enclosed, it’s time to remove the air inside with a vacuum seal. Lay all the hash pillows flat inside of the plastic vacuum seal bag. You can place as many rosin bags side-by-side as will fit inside of the vacuum seal bag. Then use the vacuum sealing machine to remove all the air inside the bag, until everything inside is nice and tight and compact. 


If the hash you’re working with is incredibly melty, you may actually squeeze some resin out of the trichomes during the vacuum sealing process. This can in turn make everything inside the bag sticky and difficult to handle. To mitigate the mess with super melty resin, wrap the hash pillows in parchment paper before slipping them into the plastic vacuum seal bag. 

While it’s helpful to leave a cushion of air inside the vacuum seal bag when enclosing fresh frozen flowers, there’s no need when vacuum sealing rosin bags. Allow the machine to remove all the air inside the plastic bag, and fully compress the hash pillows. 

Place these vacuum-sealed bags in the refrigerator overnight. 

5. Fold the Parchment for Directional Flow
Cut parchment paper to fit the bags you’re using. Use a piece of parchment that’s about three times the length of the hash pillows. If you’re pressing multiple bags at once, go three times the length of both bags put together. Fold the parchment for directional flow, which moves the rosin away from the heat as quickly as possible. The key is in the creases of the fold, which guides the flow of the rosin where you want it, away from the heated plates quickly. 

Read more about directional flow in our article The Directional Flow Method Tutorial. 

6. Press and Collect the Hash Rosin
There’s no exact time, temperature, and pressure to use for pressing hash rosin. But a good guideline is 140-200 degrees Fahrenheit at 500-1500 platen PSI. Use a 30-45 second pre-heat and press for anywhere between 15 and 90 seconds. 

Read more in How To Press Bubble Hash Rosin Guide. 

Let the rosin drip from the parchment directly into a glass jar, as opposed to spilling off and puddling up onto a separate piece of parchment paper. Letting the rosin run down in long streams across the parchment and then spilling onto a sheet of parchment increases exposure to air and oxidation.



Vacuum sealing hash pillows removes air pockets from loose resin before pressing. Vacuum sealing your rosin bags in plastic bags offers several benefits, including improved rosin clarity (reduced bubbles in the rosin), decreased risk of blowouts, and saving the extra step of pre-pressing the bags before extraction. 

All you need is a vacuum sealing machine and a few vacuum plastic bags and you can quickly vacuum seal your hash pillows before your next press. Enjoy clearer rosin and an efficient press with less risk of blowouts when pressing a massive amount of loose resin. 

Triple-bagging rosin bags using two 25-micron bags and one 160-micron bag is the best approach. 

What do you think about Vacuum Seal Tek? Let us know in the comments!

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.


What is Vacuum Seal Tek?
Vacuum seal tek is a way to remove the air from hash pillows before pressing hash rosin.

What are the benefits of Vacuum Seal Tek?
The benefits of vacuum seal tek include improved rosin clarity (reduced bubbles in the rosin), decreased risk of blowouts, and saving the extra step of pre-pressing the bags before extraction.

What equipment do you need for Vacuum Seal Tek?
The main things you need for vacuum seal tek is a vacuum seal machine, vacuum bags, parchment paper, and rosin bags (25-micron and 160-micron).

How many rosin bags do you use for Vacuum Seal Tek?
It’s best to triple-bag your loose resin with two 25-micron bags and one 160-micron rosin bag.

What micron rosin bags should you use for vacuum seal tek?
Two 25-micron bags and one 160-micron bag are best for pressing hash with vacuum seal tek.


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