A rosin press separates resin from plant material using only heat and pressure, with no solvents: two heated plates squeeze a filter bag and the melted resin flows out onto silicone paper. Typical starting points are 85–105 °C for flowers and 65–90 °C for dry sift and ice water resin, for 30–180 seconds. The effective pressure on the bag ranges from about 20 to 70 bar.
In brief
- What matters is the pressure on the material, not just the tonnage of the press.
- Bags of 90–160 µm for flowers, 25–45 µm for dry sift and ice water resin.
- Lower temperatures give less yield but preserve aromas better.
- Heat-resistant gloves, fingers away from the plates and cleaning only when the press is cold.
How a rosin press works and the main types
Trichomes, the glands covering flowers and small leaves, contain a resin that softens with heat. The plates warm it, pressure pushes it out through the mesh of the bag, and the plant material stays inside. The result is called rosin. The process uses no solvents, but it concentrates everything the resin contains. Presses differ in how they generate force:
- Manual (lever or screw): compact and affordable, suited to small amounts; the smallest work with forces of around 0.5–1 tonne.
- Hydraulic: a hand pump generates from 2 up to 20 tonnes; lots of force for little effort, but pressure is harder to fine-tune.
- Pneumatic and automatic: force comes from a compressor or motor; pressure and timings are repeatable, but the cost is higher.
Tonnage alone does not tell you how much pressure reaches the material: what counts is the area of the bag. A force of 1 tonne on a 5 × 10 cm bag (50 cm²) gives about 20 bar, enough for dry sift and ice water resin but too little for flowers; bringing the same bag of flowers to 40–70 bar takes about 2–3.5 tonnes. Larger plates take larger bags, which in turn need more force. On hydraulic presses the gauge shows the pressure in the circuit or the force, not the pressure on the material.
Temperature, time and pressure for each material
The values in the table are typical starting ranges, not fixed recipes: every press and every material behaves differently. Start at the lowest value and raise one parameter at a time.
| Material | Temperature | Time | Pressure on the material | Bag |
|---|---|---|---|---|
| Cured flowers | 85–105 °C | 30–120 s | 40–70 bar (about 600–1,000 psi) | 90–160 µm |
| Dry sift | 70–90 °C | 30–90 s | 20–50 bar (about 300–700 psi) | 25–45 µm |
| Ice water resin | 65–85 °C | 60–180 s | 20–50 bar (about 300–700 psi) | 25–45 µm |
The general rule: more heat raises the yield but breaks down terpenes and darkens the product; less heat gives a lighter, more aromatic rosin with a lower yield. Resin separated with the Ice-O-Lator or a dry sieve is pressed cooler and longer than flowers, because it contains little plant material. How to obtain it is explained in the Ice-O-Lator guide.
Filter bags, silicone paper and pressing step by step
The filter bag, made of food-grade nylon, holds back the plant material: coarse mesh (90–160 µm) is for flowers, fine mesh (25–45 µm) for dry sift and ice water resin. A bag that is too fine slows the flow with flowers, while one that is too coarse lets plant particles through. Silicone paper goes above and below it, non-stick and heat-resistant, so the rosin peels off easily once it has cooled.
- Bring the flowers to the right moisture, around 58–62% after curing: too dry and they soak up the rosin, too moist and they produce steam and bubbles.
- Preheat the plates to the chosen temperature and wait until it is stable.
- Fill the bag evenly without overfilling it and, if possible, compact the material in a pre-press mould.
- Fold the silicone paper like a book and place the bag in the middle, leaving enough margin for the rosin to flow.
- Close the plates without pressure for 10–20 seconds, then increase the pressure gradually.
- Hold the pressure for the planned time; when the flow stops, open the press.
- Wearing heat-resistant gloves, move the paper onto a cold surface and collect the rosin with a small stainless steel spatula once it has cooled.
Yield: how much you get and what it depends on
Yield is the weight of the rosin divided by the weight of the material pressed. The typical ranges reported for solventless processing are:
- Flowers: about 10–25% of the weight.
- Dry sift: about 30–60%.
- Ice water resin: about 50–80%.
Within these ranges, the main factors are the quantity and maturity of the trichomes, the moisture and freshness of the material, the combination of temperature, pressure and time, and how full the bag is: too much material in a small bag traps resin inside. Fan leaves and trim that is poor in trichomes yield little; with leftovers from trimming it usually pays to separate the resin first with ice water or a sieve. Note the weights, temperature, time and pressure for every press: after a few runs you will find the right combination for your material. Tools for preparing it are in the harvest and processing collection.
Safety, cleaning and storage
- Heat: the plates run at 65–105 °C and stay hot for a long time; wear heat-resistant gloves and do not touch the plates or freshly removed paper.
- Pressure: keep fingers out of the closing area, place the press on a stable surface and never exceed the maximum force stated by the manufacturer; on hydraulic and pneumatic presses, check hoses and fittings.
- Electricity: earthed socket, cable away from the plates, never leave the press switched on unattended.
- Cleaning: only with the press switched off, unplugged and cold, using paper or a cloth dampened with isopropyl alcohol; alcohol is flammable and must never be used on hot surfaces.
- Hygiene: nitrile gloves, clean surfaces, fresh paper and bags for every press.
Rosin keeps in tightly closed glass or silicone containers, in a cool, dark place: a few weeks in the fridge, longer in the freezer. Let a cold container reach room temperature before opening it so no condensation forms. Label each container with the date and starting material.
Frequently asked questions
What temperature should you press at?
As a starting point, 85–105 °C for flowers, 70–90 °C for dry sift and 65–85 °C for ice water resin. Start at the lowest value and raise it a few degrees at a time.
How much rosin do you get from flowers?
Usually between 10% and 25% of the weight of the flowers pressed. The result depends mainly on trichome coverage, the moisture of the material and the press settings.
Which micron filter bag should you use?
For flowers 90–160 µm, for dry sift and ice water resin 25–45 µm. The finer the mesh, the cleaner the rosin but the slower the flow.
What is the difference between a manual, hydraulic and pneumatic press?
A manual press, lever or screw, is compact and affordable but develops little force, enough for small amounts. A hydraulic press generates 2 to 20 tonnes with a hand pump, while a pneumatic press uses a compressor and makes pressure and timings more repeatable, at a higher cost.
Presses and accessories are in the presses collection.
Updated on 13 October 2026.