Solventless extraction is one of those techniques that sounds complicated and turns out to be almost embarrassingly simple. No butane, no ethanol, no vacuum ovens, no purging, no residual solvent testing. Just heat and pressure applied to plant material, and what comes out the other side is the plant's own resin.
That's what a rosin press does. If you're working with aromatic or resinous botanicals and you've been put off extraction by the cost, the chemistry or the fire risk, this is the method worth knowing about.
How rosin pressing works
Plant material goes into a filter bag. The bag sits between two heated plates. Pressure is applied — by a hand-worked lever driving a hydraulic cylinder, or by an electric pump on automatic models — and the heat lowers the viscosity of the resins held in the material until they flow.
Under pressure, those resins are squeezed out through the mesh of the filter bag, leaving the plant fibre behind. The extract collects on release paper either side of the bag, and you scrape it off once it's cooled.
That's the whole process. The skill is entirely in the variables.
The four things that determine your result
Temperature. The single biggest lever. Lower temperatures — roughly 70–90°C — produce a thicker, lighter-coloured extract with better retention of volatile aromatics, because those compounds are the first to be lost to heat. Higher temperatures, up to around 120°C, give a looser, darker extract and a noticeably higher yield. There's no correct answer, just a trade-off between aroma and quantity, and where you sit on it depends on what you're making.
Pressure. More is not automatically better. Excessive pressure ruptures the filter bag or forces plant fibre through the mesh, which contaminates the extract. Build pressure gradually and watch for the point where flow slows — that's usually the useful limit.
Time. Most presses run 60 to 180 seconds. Longer at lower temperature is generally kinder to the aromatics than shorter at high temperature.
Material preparation. Moisture content matters enormously. Material that's too wet produces a watery, unstable extract that won't hold together. Too dry and the resins won't flow properly. Somewhere around 10–12% moisture is the usual target, and it's worth buying a cheap moisture meter rather than guessing.
Why plate area beats tonnage
This is the specification most people get wrong when buying. A 20-tonne press is not twice as good as a 10-tonne press. What actually matters is pressure per unit area — PSI — and that's a function of force divided by the plate contact area.
A 10-tonne cylinder acting across a small plate generates far higher PSI than a 20-tonne cylinder spread across large plates. The bigger press isn't pressing harder; it's pressing more at once.
So the question isn't "how many tonnes do I need?" It's "how much material do I want to process per cycle?" Answer that, pick the plate size that fits, and the tonnage requirement follows. Graveda's range is built around that logic — their smaller units use compact plates at high PSI, and the larger models scale plate area with cylinder force to keep the pressure in the same useful window.
Why Graveda
Graveda are a German manufacturer who specialise in presses rather than treating them as one line among many. Two things stand out.
German manufacturing control. On a press this shows up in the things that fail on cheaper equipment — plates that heat evenly across their whole surface rather than running hot in the middle, cylinders that hold pressure without creeping, frames that don't flex under load.
A range that actually scales. The Graspresso line runs from the GP6003 3 Ton through the GP30-5 5 Ton and GP50-5-7 7 Ton, up to the EPIC 15 Ton and the GMP 20 Ton with hydraulic cylinder and manometer. That last feature matters more than it sounds, because without a gauge you can't record what you did, and if you can't record it you can't repeat it.
Graveda also make the supporting kit. The press filter bags run from 5 to 220 micron across eleven ratings, in two bag sizes, ten to a pack — dimensioned around Graveda's own plates, so nothing needs improvising.
Choosing a model
The GP6003 3 Ton is the entry point. The most affordable press in the range and genuinely capable for small batches — good for finding out whether you enjoy the process before committing real money.
The GP30-5 5 Ton is where most serious hobbyists land. Enough force for consistent results, plates sized for realistic batches, and still compact enough to live on a bench.
The GP50-5-7 7 Ton is the bracket for anyone pressing regularly rather than occasionally. The extra force lets you work a fuller bag per cycle without dropping below the PSI you need, which is the difference between a press you experiment with and one you actually rely on.
The EPIC 15 Ton and the GMP 20 Ton are production equipment. The GMP pairs its hydraulic cylinder with a manometer, so you can read and log the pressure you actually applied rather than estimating it. Check weight and footprint before ordering — the largest units are heavy enough to need two people to position.
Getting better results
Pre-press first. Forming your material into a dense puck that matches your bag dimensions before it goes near the plates makes a substantial difference. It removes air, ensures even pressure distribution and reduces blowouts. A pre-press mould pays for itself quickly.
Match your micron to your material. Coarser mesh (120–220 micron) flows faster but lets more fibre through. Finer mesh (5–45 micron) gives a cleaner extract at the cost of yield. Start around 90 micron and adjust — Graveda's filter bags cover eleven ratings, so you can work through the range without changing supplier.
Fold the bag correctly. Fold the open end over rather than leaving it loose, and orient the fold away from your collection point.
Use fresh release paper each press. It's inexpensive and it prevents flavour carryover between different botanicals.
Collect while warm, store cold. Extract scrapes off far more easily at around 30–40°C. Once collected, cold storage in an airtight container preserves the volatile compounds you worked to keep.
Keep a log. Temperature, pressure, time, micron, material weight, yield. Six entries in and you'll have a recipe.
What people use rosin presses for
Solventless botanical extraction has applications well beyond one crop:
- Craft brewing — hop rosin has become a serious technique for late additions and dry hopping, delivering concentrated aroma without vegetal material or the volume loss of whole-cone hops
- Herbalism and balm making — oleoresins from rosemary, calendula, lavender, arnica and St John's wort, extracted without solvent residues
- Incense and perfumery — working frankincense, myrrh, benzoin and pine resins into refined concentrates
- Culinary work — citrus peel, vanilla and spice oleoresins for high-intensity flavouring
- Beekeeping — propolis processing into usable extract form
- Cosmetics and soap making — botanical concentrates for natural scenting and active ingredients
Frequently asked questions
Is rosin pressing genuinely solvent-free? Yes. The only inputs are heat and mechanical pressure. Nothing is added and nothing needs purging afterwards, which is why it appeals to people making products for skin or consumption.
What temperature should I start at? Around 90°C is a sensible first attempt for most resinous botanicals. Adjust down for aroma, up for yield, and change one variable at a time.
Do I need heated plates, or will an unheated press work? Heated plates are essential for rosin extraction. Without heat the resins stay too viscous to flow, and you'll just compress the material rather than extracting from it.
How much material per press? Plate size dictates it. Smaller plates handle a few grams; the XL plates on the largest models take considerably more. Overfilling is the most common beginner error and causes bag failures.
How long do the plates last? Indefinitely with reasonable care. Use release paper, don't scrape the plate surfaces with metal tools, and wipe them down while warm.
Manual or automatic? Manual gives you tactile feedback — you feel resistance change as the resin flows, which is genuinely informative. Automatic gives consistency and saves your shoulders.
Browse the Graveda range
The full Graveda Graspresso range is available at Green Spirit Horticulture, with next-day UK delivery and click-and-collect from our Sheffield and Barnsley stores. If you're unsure which tonnage and plate size suit your volume, ring us on 0114 275 3353 — our staff use this equipment and will give you a straight answer.
Graveda presses are supplied for lawful horticultural, culinary and craft applications only.
