Summer bushfires and bad weather at each critical growth point of wine grapes have tested the industry.While final numbers are not known yet, the South Australian Wine Industry Association (SAWIA) estimates yields this year will be down 50 per cent overall, with some regions worse off."We've had early frosts, we've had wind around the time of flowering, we've had extreme heat and we've also had the economic challenges rising out of COVID-19," said chief executive, Brian Smedley."2020 will be a light year for us, the yield is less than last year and the long-term average."The one positive for the 2020 vintage is that quality is up — there just will not be much to drink."I think the intensity of the flavours [will be there]," Mr Smedley said."We've been fortunate of having a vintage that's been spread out over time and so that's led to good ripening and good quality."