Pressing wax (commonly called rosin) involves using heat and pressure to squeeze resinous oil out of cannabis flower or hash, producing a solventless concentrate you can dab or vaporize. The process is straightforward: you place your material between two heated plates, apply force, and collect the golden oil that flows out onto parchment paper. No solvents, no chemicals, and results in minutes.
Cannabinoids are semi-liquid at relatively low temperatures, which is what makes this work. Enough heat softens the resin glands on the plant material, and mechanical pressure forces that molten resin through the plant structure and out onto your collection surface. The key is dialing in the right combination of temperature, pressure, and time for whatever material you’re starting with.
Equipment You Need
At minimum, you need a rosin press with heated plates, unbleached parchment paper, filter bags, and a collection tool like a metal dabber or scraper. A pre-press mold is optional but helpful: it compacts your material into a uniform puck before pressing, which leads to more even extraction and better yields.
Rosin presses range from small handheld or tabletop units with a few tons of force to larger hydraulic or pneumatic setups. For personal use, a press capable of generating several tons of force with 3×5 or 4×7 inch plates covers most needs. Parchment paper is essential because it’s heat-resistant and keeps the rosin from sticking to surfaces. Use parchment specifically rated for heat, not wax paper, which will melt and contaminate your product. Your collection tool should be stainless steel or another non-reactive material.
Preparing Your Starting Material
The quality and condition of your starting material matters more than any other variable. For flower, the ideal relative humidity sits between 58% and 65%. This range allows optimal resin flow and helps preserve the aromatic terpenes that give your rosin its flavor profile. Too dry and the material crumbles, producing dark, harsh-tasting rosin. Too wet and steam interferes with clean extraction. Humidity control packs stored with your flower for 24 to 48 hours before pressing are the easiest way to hit this window.
If you’re pressing bubble hash or dry sift (kief), moisture is less of a concern, but quality still dictates results. Higher-grade hash with more trichome heads and less plant contamination produces cleaner, lighter-colored rosin with significantly better yields.
Choosing the Right Filter Bag
Filter bags (also called micron bags or rosin bags) act as a screen that lets resin through while holding back plant material and contaminants. The micron rating tells you how fine the mesh is, and different materials need different sizes:
- Flower: 160 microns. The larger openings accommodate bulkier plant material while still filtering out unwanted particulate.
- Dry sift or kief: 25 to 75 microns. Since the material is already partially refined, a tighter mesh produces cleaner rosin.
- Bubble hash: 5 to 37 microns. Hash is the most refined starting material, so very fine bags yield the purest product.
Lower micron counts produce cleaner rosin with better color and flavor but slightly lower yields. Higher micron counts let more material through, increasing yield at the cost of some purity. Most people find a middle ground within these ranges.
Temperature Settings
Temperature is where you balance yield against quality. Lower temperatures preserve more terpenes and produce a lighter, more flavorful product. Higher temperatures push out more oil but sacrifice some of those volatile flavor compounds.
For flower, the working range is 180°F to 220°F. A “cold press” between 180°F and 200°F delivers superior flavor and a lighter color. A “hot press” between 200°F and 220°F maximizes yield. The sweet spot for most people pressing flower falls between 200°F and 210°F, balancing both quality and return.
For bubble hash and dry sift, temperatures run lower: 140°F to 200°F. Cold pressing these materials at 140°F to 170°F preserves the most terpenes, while 170°F to 200°F increases yield. Many hash pressers work around 150°F to 160°F for the best balance.
For context on why these temperatures matter: myrcene, one of the most common terpenes in cannabis, begins to vaporize around 331°F, and limonene at about 351°F. Pressing well below those thresholds means you’re keeping most of those flavor and aroma compounds intact in your rosin rather than losing them as vapor during extraction.
How Much Pressure to Apply
Pressure is measured in PSI at the plate surface, not the raw tonnage of your press. To find your actual plate PSI, divide the total force your press generates by the surface area of your material. A 10-ton press sounds powerful, but spread across a large bag of flower, the PSI at the material may be moderate.
Target ranges by material:
- Flower: 1,000 to 2,000 PSI at the plate
- Bubble hash: 500 to 1,500 PSI
- Dry sift: 500 to 1,500 PSI
Hash and sift need less pressure because the trichomes have already been separated from the plant. Too much pressure on these materials forces plant lipids and waxes into your rosin, darkening it and muddying the flavor. With flower, you need more force to push resin through the denser plant structure, but going above 2,000 PSI typically just squeezes out chlorophyll and other unwanted compounds.
The Pressing Process Step by Step
Set your plates to your target temperature and let them stabilize. While they heat, load your material into the appropriate filter bag and, if you have a pre-press mold, compact it into a flat puck. Place the loaded bag between a folded sheet of parchment paper, leaving plenty of extra parchment on all sides for the rosin to flow onto.
Start with a preheat phase. For flower, close the plates gently onto your material with light pressure and hold for 30 to 90 seconds. This warms the resin inside the trichome heads without immediately forcing it out, allowing for a smoother, more complete flow. For hash and dry sift, preheat for 30 to 45 seconds.
After preheating, gradually ramp up to full pressure. The total pressing time for flower runs 60 to 180 seconds. For bubble hash and dry sift, you need less time: 15 to 90 seconds under full pressure. You’ll see rosin begin to flow out from the edges of the bag onto the parchment. When the flow slows to a trickle or stops, the press is done. Release pressure and remove the parchment.
Let the parchment cool for a moment, then use your collection tool to scrape the rosin off. Fresh rosin is sticky and pliable. Collecting it while slightly cool makes scraping easier.
What to Expect for Yields
Yields vary significantly based on your starting material’s quality, strain, and freshness. Flower typically returns 15% to 25% of its weight as rosin, meaning a 7-gram press might produce 1 to 1.75 grams. Ice water hash yields are much higher, around 65% to 80%, because you’re starting with a material that’s already mostly trichome heads.
If your yields fall below these ranges, check your humidity levels, try adjusting temperature up by 5 to 10 degrees, or experiment with slightly longer press times. Strain selection also plays a major role. Resinous, trichome-heavy cultivars simply produce more rosin than less frosty varieties, regardless of technique.
Curing Rosin After Pressing
Freshly pressed rosin is usable immediately, but curing changes its texture, consistency, and sometimes its flavor. There are two main approaches.
Cold curing involves placing your rosin in a sealed glass jar at 60°F to 70°F (keeping it under 65°F if possible) for 24 to 72 hours, sometimes up to a full week. Over this period, the rosin gradually changes from a glassy, sappy texture to a more opaque, badder-like consistency. Cold curing preserves terpenes well and requires no special equipment beyond a jar and a cool room.
Warm curing speeds up the process. Place your sealed jar on a heating pad set to around 100°F, or between press plates set to 125°F to 135°F. Check the consistency after about an hour and continue as needed, typically for a few hours up to a day or two. This approach produces a more homogenized, buttery texture faster. Keeping temperatures on the lower end of the 90°F to 130°F range preserves more terpenes during the cure.
Neither method is objectively better. Cold curing tends to favor flavor preservation, while warm curing offers convenience and a smoother final texture. Many people try both and settle on a preference based on the consistency they enjoy most.