The UK's wine drinking population has probably peaked at around 28 million, according to new analysis from Wine Intelligence.
Director Brian Howard said that the industry needed to work harder to engage with "millennials": drinkers aged between 18 and 34.
"Unless we proactively bring them into our category the pool of wine consumers will decline," he told a seminar at the London International Wine Fair, hosted by the Wine & Spirit Trade Association.
"We are not as an industry winning the battle to raise consumer involvement and engagement with our category.
"There may be a positive explanation in that as the pool has increased, the newcomers tend to be less involved with wine although they do drink it regularly.
"That's good for churn and volume but it may not be good for creating value and bringing people into the category to the extent that they want to trade up."
The seminar heard that, since March 2007, regular wine drinkers in the UK have been drinking more rosé, Pinot Grigio, Tempranillo and Malbec but less Chardonnay and Cabernet Sauvignon.
Countries which have increased in popularity include New Zealand and South Africa, according to the Wine Intelligence consumer research, while Australia and France have seen declines.
Howard said the rising acceptance of lower ABV wines could be compared to the way screwcaps gradually gained favour with consumers in recent years, although it was still too early to be sure the pattern would be replicated exactly.
He said that price and promotion had become increasingly important to UK consumers, and was the number one buying cue. Fewer consumers say they are influenced by a friend or family member's recommendation than was the case three years ago, a finding Howard described as "concerning".