Dealcoholisation methods Membrane techniques
MethodOsmotic distillation
Ethanol crosses a hydrophobic membrane as vapour, with no high pressure and no boiling. It is not reverse osmosis.
- 1 Contactor Wine and strip water on either side of a hydrophobic membrane.
- 2 Vapour Ethanol crosses the pore as gas; liquid does not wet it.
- 3 Hybrid Memstar runs this on RO/NF permeate, not on whole wine.
| Driving force | Vapour-pressure and concentration gradient |
|---|---|
| What leaves | Ethanol (and some volatiles) as vapour |
| What happens to water | The wine’s water barely leaves |
| Heat | Ambient, atmospheric pressure |
| Type | Method Part of Membrane techniques |
|---|---|
| Developer | Generic technique; the best-known commercial scheme is Memstar |
| Volume loss | That of the ethanol removed; the wine’s water does not leave with it |
| Final ABV | Mostly partial cuts; 0.0% needs many cycles |
| Wines known to use it | No 0.0% brand credits it on the label; industrial use (Memstar) |
| Best for | Cutting strength without heat and without putting water back, especially in reds where phenolics matter. |
What it is
Osmotic distillation (also evaporative perstraction, or dealcoholisation on a membrane contactor) is a membrane technique. It is not thermal distillation and it is not osmosis. Regulation (EU) 2021/2117 authorises it as a membrane technique, on the same footing as reverse osmosis, not as a footnote to it.
Wine and a stripping agent (almost always water) run on either side of a hydrophobic, microporous membrane. Liquid does not wet the pore. Ethanol, the most volatile component, goes to vapour, crosses the pore and dissolves in the water on the other side. The driving force is the difference in vapour pressure and concentration, not a high-pressure pump. It runs at ambient temperature and atmospheric pressure.
How it is not reverse osmosis
In reverse osmosis the wine is forced against a dense filter and ethanol and water leave together as liquid. Here the wine does not cross the membrane. Only ethanol (and, to a lesser extent, other volatiles) does. The wine’s water content barely changes: volume loss is, in essence, the alcohol that has gone. There is no need for diafiltration or RO make-up water.
That is why reviews of phenolic composition in reds often rank osmotic distillation ahead of reverse osmosis when the aim is not to pull the structure apart. The cost is that esters also like that hydrophobic membrane: drop the strength too far and the nose fades.
The Memstar hybrid
On the plant floor it is almost never run on whole wine. Memstar’s patented scheme (Australia; in Europe VAF Memstar is among the operators) first sends the wine through reverse osmosis or nanofiltration, and osmotic distillation then works only on the permeate, which already holds little of what gives colour and tannin. The dealcoholised permeate is blended back with the retentate. Each pass typically takes off 1–2% ABV. That is a modification: two membrane techniques in series, not a third method. The maker’s point is that there is no classical distillation, and the real wine never meets the strip water.
The numbers
There is no catalogue “final ABV” to match GoLo’s 0.05%. The literature and industrial services use it mainly for partial cuts (1–3% ABV, sometimes down to about 10.5% ABV in trials). Taking a wine to 0.0% is possible at the cost of many cycles and more aroma loss; that is not the use it is best documented for.
Wines that use it
No 0.0% wine brand has put “osmotic distillation” on the label the way Torres credits spinning cone. The public trail is B2B service (alcohol adjustment in Australia and, with mobile kit, elsewhere). This page will be updated once a brand names it.