Table wines have traditionally been produced with an alcohol content of 12-14 % v/v depending on the grape variety and growing conditions. Consumers have long accepted this alcohol concentration as a basis for the determination of their consumption limit dictated by personal health issues, intoxication susceptibility, and the requirement to remain within the blood-alcohol limits imposed by drink-driving laws.
However, in recent years there has been a gradual increase in the alcohol content of wines world-wide with alcohol concentrations of 15-17 % v/v or higher being commonplace. This has been attributed in part to climate change, with the 10 warmest years on record having occurred since 1995. Also, increasing competition between wine makers, at least in Australia, has prompted many to leave grapes on the wine longer than usual to allow increased development of the rich organic aroma and flavour components that give the wine its character. Unfortunately, this latter practice results in an over-production of fermentable sugars with a resulting increase in alcohol content following fermentation. Consumer demand for a return to traditional alcohol levels has led to the development of several alcohol reduction processes. These developments have also been driven by a demand for wine having an alcohol content as low as 5 % v/v.
A problem common to all of these processes is the loss of the volatile aroma and flavor components that give the wine its character.
Dreamtime Technologies process
The Dreamtime Alcohol Removal process is a membrane-based process that allows the alcohol content to be reduced to any desired level with minimal loss of volatiles. The process operates at or below ambient temperature with no applied pressure. The pure water strip stream accumulates alcohol and may be used as an additive in the production of other types of low-alcohol beverages. This avoids duties payable on the alcohol strip stream in some countries.
Benefits of the Dreamtime Technologies process
The benefits of the Dreamtime Technologies process are:
• high selectivity to ethanol removal
• tailoring of performance to different wines by manipulation of operational conditions to target inhibition of removal of strategic flavour compounds
• no high pressure requirements
• low energy consumption
• ease of use and process simplicity
Dreamtime Technologies has designed a treatment plant capable of scalping 30,000 litres of wine per day based on a 20 hour day The plant is also capable of producing wines with substantially lower alcohol levels albeit at reduced throughput.