Guide to Micron Bag Sizes for Rosin Presses
Micron bags are essential for a clean and effective rosin press. Getting the right pore size (measured in microns) for pressing rosin makes a big difference to rosin color and flavor as well as yield and the likelihood of blowouts.
A micron is a unit of measurement that is equal to one-thousandth of a millimeter. The micron size refers to the distance between the filaments in the filter, with smaller microns resulting in a finer texture and larger microns resulting in a coarser texture.
Small Micron Bags: 5µm, 15µm, 25µm, 37µm, and 50µm
A small micron bag is recommended if you plan to press rosin from cannabis extracts like bubble hash, dry sift, and kief on a rosin press. These extracts consist of cannabis trichomes, which range in size from approximately 25µm on the small side to around 160µm on the large side. In some strains, the range is smaller: trichome heads with diameters of 40µm to 110µm were observed in Moby Dick and Space Queen genotypes in one 2023 study.
A small micron size is essential for pressing extracts, as the trichome heads would fall through the holes of a larger micron bag size. 5 to 37 microns are typically cited as the range for pressing bubble hash and 25 to 75 microns are recommended for pressing dry sift or kief. You will need to use a fill funnel when filling the bags with the extracts named above.
Our Preferred Small Micron Size
We usually opt for 25µm rosin bags as the sweet spot in this range. We will also double-bag for additional support in most cases, such as when producing Clear Tech Rosin or pressing very fine hash.
Mid-Range Micron Bags: 75µm, 90µm, 120µm, and 160µm
Mid-sized micron bags are generally used for making flower rosin rather than hash rosin because the best-quality trichome heads (found in the 90µm to 120µm range) would fall right through the holes. When pressing flower or trim, however, mid-sized micron pores block the plant matter while allowing the resin to flow out through the holes in the rosin bag. These widths are also the best microns for making bubble hash (but not for pressing it).
Our Platinum Stitch Micron Bags come in 160µm for pressing flower as well as 25µm for pressing bubble hash. These bags are compatible with our Billet All American Pre Presses. A pre-press mold can be used to press your flower into a brick to maximize the amount of material that can be pressed in one go.
Large Micron Bags: 220µm
Large micron sizes are primarily used for providing structural support and preventing blowouts (burst rosin bags). This is helpful when you are pressing double-bagged bubble hash, for example. Please note that you should avoid overfilling the bags as this can also cause blowouts.
Our 220µm Bulletproof Stitchless Rosin Pouches are welded together rather than stitched for unparalleled strength and resilience. We developed this much more rigid “Bulletproof” bag a few years back specifically to limit the amount that a single or double-bagged 25µm rosin bag can stretch during pressing (the 25µm rosin bags typically stretch and squeeze significantly during the rosin pressing process) and keep everything in place. We recommend these bags for providing structural support for both hash and flower presses.
Rosin Bag Usage Tips
The following tips will help you get the best results from your rosin bags.
Use High-Quality Starting Material
Your rosin will only be as good as your starting material, no matter which micron size you use. Freeze-dried live bubble hash is the most premium starting material for rosin.
However, kief, dry sift, bubble hash, and even dried flower from any of the best strains for rosin production should give you great results if it has been stored in cool conditions since harvest, has the right humidity level, and is mold-free.
Use the Correct Micron Size for Your Starting Material
Micron size affects both quality and yield in rosin extraction. Smaller microns generally result in a lower yield but a lighter rosin color because less plant material can make its way through the holes. Larger micron sizes produce a higher yield but a potentially "greener" rosin—especially when pressing flower.
Use New Rosin Bags Each Time
Using new rosin bags each time will give you the most accurate results. While you can technically reuse rosin bags, this is not recommended because it increases the probability of blowouts.
You can also repress the same rosin bags a second time without removing the spent rosin chip. However, the yield will be much lower and will contain more plant material (and/or trichome cuticles) depending on the temperatures and pressures used. Rosin from a second press is only suitable for making topicals or edibles.
Microns Matter
Rosin bags are produced in several micron sizes to help solventless extractors optimize their presses for both hash and flower. Smaller holes are best for pressing pre-refined cannabis products like kief, dry sift, and bubble hash. Medium-size holes are best if you’re pressing flower.
Finding the micron size that optimizes both yield and quality takes some experimentation and might vary according to the starting product and strain. Choosing high-quality micron bags and adding structural support when necessary is also essential for preventing blowouts and achieving the best results.