THE distillery process used by Bill Lynam to make grappa at his Ballandean property was akin to a "backyard still", an expert has told Toowoomba Supreme Court.
Senior lecturer in wine science at the University of Adelaide, Dr David Jeffery, was provided photographs of the three-still set up used by the 71-year-old and analysis reports of tests done on a number of liquid products found at the Lynam property.
He explained the distilling process was meant to extract the poisonous methanol from the oxidised wine collected by Mr Lynam to leave ethanol (alcohol) and waste.
He said the first 1% extracted was the "head", the next was the "heart", which, when distilled again became the beverage, while what was left was the "tail" which was usually discarded.
The court has heard Mr Lynam told police the "head" was poisonous and used as weed killer.
Mr Lynam's son Joel, 21, and friends Vincent Summers, 21, and Bryan Wilmot, 30, are alleged to have died from methanol toxicity after drinking home-made grappa made by Mr Lynam at the family's Puglisi Lane property on June 7, 2013.
His other son Joshua was the sole survivor but sustained organ failure and spent four days in intensive care.
Joshua told police he had drunk less than the others.
Mr Lynam has pleaded not guilty to three counts of manslaughter and one count of grievous bodily harm.
The Crown claims he did not intend to harm anyone but was criminally negligent in providing the brew for the four young men without taking proper care.
Dr Jeffery said most of the results of samples provided to him for examination appeared to show the methanol level within reasonable amounts but at least two samples had methanol levels far above the legal limit set by Food Standards Australia.
Dr Jeffery said he didn't understand how some samples could have such high levels of methanol.
Methanol forms in small amounts during fermentation.
The court heard just 10ml of methanol could prove toxic to a person's central nervous system and cause vision problems.
Consuming between 100 and 200ml of methanol was generally fatal for most adults.
Each of the deceased men were found to have methanol/blood readings three, four and more times that level, the court heard.
Dr Jeffery was the last witness to be called by the Crown which is expected to close its case Monday morning.
Justice Ann Lyons told the jury it could expect to retire to consider a verdict in the case on Tuesday or Wednesday next week after closing addresses.
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