Growers say the dry June followed by a wet July created perfect growing conditions.
Andy Hares, 49, boss of New Hall Vineyards in Essex, said: “This has the potential to be one of the best years for the last 10 to 15 for us, both in terms of the grape quality and yield.”
Last year Mr Hares’ yield was down about a third but this year, instead of the typical 250,000 bottles, he expects 300,000.
The warm, dry June meant that fragile flowering vines avoided the risk of frost, mildew and over-watering.
The rain came when the grapes were hardy, green and able to withstand Storm Antoni.
Kristen Syltevik, 57, owner of Oxney vineyard in East Sussex, said: “Now we need to have really gorgeous weather for two months.
“If it rains it’s hard to get the right ripeness. Because we’re organic it’s a bigger challenge for us, but it’s never rained for two to three months in a row so hopefully we will be OK.”
Ryan Davies, 36, boss of Llanerch Vineyard Hotel in South Wales, is also expecting a “heavy harvest” if mildew is kept at bay.
Mr Davies added: “The UK wine scene is still on the up. Every year we have increased and there’s still room for the industry to grow.”
The UK is now home to 900 vineyards and 200 wineries spanning Wales, Cornwall, Derbyshire, Lincolnshire, North Yorkshire and Scotland.
More than 12 million bottles were produced last year, mostly sparkling.
