The trend is here – low to ZERO alcohol wine. But how does one go about getting regular wine to less than 0.5% v/v alcohol without damaging the underlying product?
There are several techniques that can be used for removing ethanol from wine effectively. Some are more effective than others and some depend on the target ethanol percentage you are shooting for. The following are the mainstream, readily available, options available to the US wine industry.
- – Reverse Osmosis
- – Direct contact membrane distillation – also known as Perstraction
- – Vacuum distillation
Each of the above processes have pros and cons related to target ethanol, equipment cost, temperature and volume of wastewater generated.
Please note, a DSP license is required to remove ethanol from wine on site.
Reverse Osmosis (RO)
The use of high rejection RO membranes to effectively ‘wash out’ the ethanol has been in use for some time to make alcohol free wines. This is the most efficient on-site process for the reduction of ethanol to 0.5%. The wine is not subject to any temperature during the process. The ethanol removed is at a sufficient concentration to be transported off site to a distillation facility for recovery.
Pros
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- – Low impact removal of ethanol from wine.
- – Low product loss, only ethanol is removed.
- – Can be used on site, assuming a DSP is in place.
- – Minimal water use. 2200 gallons of water needed per 1,000 gallons of wine reduced from 12% to 0.5%.
- – The same RO machinery can be used to produce the deionized wash water ahead of time.
Cons
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- – Time consuming process, multiple passes required to reach 0.5%.
- – Potential loss of weak acids.
Direct Contact Membrane Distillation
The process of membrane distillation, sometimes called perstraction, utilizes a hydrophobic membrane contactor that allows only the ethanol vapor to cross the membrane barrier and get carried away in a water condensing stream while not allowing water to pass. The process can be operated two ways on wine, with each option resulting in different efficiencies and volumes of ethanol/water generation. Option A is running wine directly through the contactor and option B is using a first stage separation process (RO/NF or UF) and then passing the permeate from the first stage process through the membrane contactor. Efficiency is highest with option B since higher temperatures can be applied to the permeate stream increasing removal efficiency and preventing ‘burnt’ characters that would otherwise be apparent if the wine was heated directly.
Option A – Wine passed through the membrane contactor.
Pros
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- – Medium impact removal of ethanol from the wine.
- – Low loss – only ethanol is removed from the wine.
- – Ideal for target ethanol levels above 7%.
- – Can easily be operated at the winery.
- – Winemaker can ‘sweetspot’ the wine in real time.
Cons
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- – VERY high water use, increasing as the ethanol target decreases. Approx 2800-3500 gallons of water used per 1000 gallons of wine for an adjustment from 12% to 5%.
- – Slow rate of removal – high surface area of contactor required resulting in greater expense.
- – Not easy to get to 0.5% ethanol using this method.
- – If used to produce ZERO alcohol wine, approximate water use is 7,500 gallons per 1,000 gallons of wine reduced from 12% to 0.5%.
- – Recovery of the ethanol from the strip water is very costly due to low ethanol concentration.
- – Strip water ethanol concentration is less than 3% v/v when completed.
- – On site generation of strip water requires extra storage.
Option B – RO/NF/UF used to generate permeate and the permeate passed through the membrane contactor.
Pros
- – Low impact removal of ethanol from the wine.
- – Low loss – only ethanol is removed from the wine.
- – Ideal for target ethanol levels above 7%.
- – Can easily be operated at the winery.
- – Much higher removal efficiency per ft2 membrane contactor when compared to wine direct operation (200-300%).
- – Winemaker can ‘sweetspot’ the wine in real time.
- – Higher ethanol concentration in the strip water means lower cost of recovery and lower transport cost to distillation facility.
- – Stripwater ethanol strength as high as 5%-6% v/v if wine ethanol target is above 7%.
Cons
- – Not suited for ZERO alcohol wines.
- – Strip water requires pre-conditioning to prevent scale formation.
- – If used to produce ZERO alcohol wine, approximate water use is 7,500 gallons per 1,000 gallons of wine to reduce alcohol from 12% to 0.5%.
- – On site generation of strip water requires extra storage.
Vacuum Distillation
The principal behind its use for reducing ethanol in wine is to reduce the pressure on the fluid that is being de-alcoholized (de-alced) in order to reduce the boiling point of the ethanol. There are only a few of these systems available for use in the USA and mobile use is not possible. Wine will need to be shipped to and from the location of the column.
Pros
- – Can reduce ethanol to less than 0.5% in one pass.
- – Ethanol removed is at a strength that can be sold as high proof – no need for further distilling.
Cons
- – Temperature of at least 35°C – 40°C (95°F – 104°F) required.
- – Wine has to be processed off site.
- – Large overall loss – water removed along with the ethanol can be as high as 100-120 gallons per 1000 gallons of wine.
- – Equipment is VERY expensive and requires specialized permitting and significant investment.
- – Poorly performing or operated systems can cause cooked and burnt characters in the final product.
- – Equipment is large, difficult to run and requires multiple permits.
SUMMARY
There is no one ideal process to produce ZERO Alcohol wine. Vacuum distillation and RO are the top two most efficient methods to do this, with RO being possible at a winery. Membrane distillation is ideal for producing ‘lower’ alcohol wines but is not suited to produce ZERO alcohol wines.
At VA Filtration we can offer both membrane distillation and RO processes for your alcohol reduction needs. If you have a DSP license, we can carry out either process at your site. If you do not have a DSP, you can ship your product to our facility in Napa and we can process it under our DSP. Small lot trials of 5 gallons are available from starting to as low as 0.5%.
It must be noted that the production of ZERO alcohol wines requires additional additives to improve taste and quality after the alcohol is removed. This process is also not only limited to wine but can be used on beer, cider or any other product containing alcohol that requires removal.
