The boss of legendary Belgian brewery Cantillon has said he has been forced to stop production due to climate change, as an unusually warm autumn has meant temperatures are too high to cool the beer overnight.

Cantillon has been making what are considered some of the world's best sour, spontaneously fermented lambic beers in its Brussels brewery since it opened in 1900.

According to the traditional recipe, Cantillon leaves their wort, the fermenting mix of grain and warm water, overnight in the cool late October air so it is exposed to the wild yeasts around it.

As the wort cools, it draws in these airborne yeasts and mixes with them. This mixture is then transferred to barrels for fermentation.

The mix picks up more yeasts inside the barrel, enough to make it ferment - but you need the airborne yeasts to produce the best lambics.

Speaking to AFP, fourth-generation brewer Jean Van Roy said the perfect temperature for cooling is between -3C and 8C.

The ten best beers Show all 10 1 /10 The ten best beers The ten best beers The ten best beers Hawkshead

Lakeland Gold A fast-growing Cumbrian brewery founded by the former BBC correspondent Alex Brodie. The beer is pale bronze and has notes of toasted malt and tart and tangy citrus fruit from American Cascade and English First Gold hops. The finish is bitter and fruity.

Price: £29 for case of 12 Hawkshead

brewery.co.uk The ten best beers Young's Kew Gold

Some of the hops used in this beer were grown at Kew Gardens and a donation from the sales goes to support its research. The beer (to be rebranded as Young's London Gold from May) has a dazzling gold colour and the aroma and palate are dominated by tart hop resins, toasted malt and citrus fruit.

Price: £1.95

Beersofeurope.co.uk The ten best beers Titanic Stout

Titanic Brewery hails from Stoke-on-Trent, birthplace of John Smith, captain of the ill-fated liner. It has a roasted grain, coffee, liquorice and tangy hop resin aroma, with dried fruit developing in the mouth. The finish is smoky, hoppy and quenching and, like the Titanic, goes down well.

Price: £1.80

from selected Morrisons, Tesco and Waitrose The ten best beers Bateman's Spring Breeze

With a label bearing the image of Demeter, goddess of spring and fertility, this beer from a family brewery is the perfect one to herald the new season. It zings with citrus hop character, balanced by rich, juicy malt: awonderfully crisp and refreshing golden ale

. Price: £20.10 for case of 12

Ale4home.co.uk The ten best beers Adnams Tally-Ho

A famous Suffolk 'winter warmer' has been given a makeover. It's now bottle-conditioned and produced as an annual vintage. Ruby red, it has a rich aroma and palate of raisins, sultanas, walnuts, roasted grain and spicy hops.

Price: £1.49 per bottle or £35.75 for case of 24

Adnams.co.uk The ten best beers Acorn Brewery of Barnsley Gorlovka Imperial Stout

Gorlovka is Barnsley's twin town in Ukraine: the beer recalls the strong stouts exported to Imperial Russia in the 18th and 19th centuries. Ruby/black with a complex palate of roasted grain, liquorice, cocoa and peppery hops.

Price: £2.25

Acorn-brewery.co.uk The ten best beers Wye Valley HPA

A new bottled version of a cask beer that marks the 25th anniversary of Wye Valley brewery. Target hops come from local fields and the pale gold beer has tropical fruit, sherbet lemons and spicy hops on aroma and palate, followed by a dry, fruity and hoppy finish.

Price: £19.20 for case of 12

Wyevalleybrewery.co.uk The ten best beers National Trust Viceroy India Pale Ale

Brewed for the trust by Westerham Brewery in Kent, the beer celebrates Lord Curzon, who restored fine buildings in both India and England. It's honeycoloured with spicy hops, plum fruit and juicy malt on aroma and palate, and a tart, fruity and hoppy finish.

Price: £23 for case of 12

Westerhambrewery.co.uk The ten best beers Greene King Strong Suffolk Ale

History in a glass – a rare example of an 18th-century 'country beer', a blend of Best Pale Ale and Old 5X, matured for a year or more in wooden vessels. It has a spicy, oaky, sherry wine and iron-like bitterness on aroma and palate with a hint of sourness from wood ageing.

Price: £1.99

Beersofeurope.co.uk

However, due to the changing climate, winters have become warmer and these temperatures have become harder to reach - and this year's unseasonable warmth has meant that some of their brews aren't cooling at all.

Van Roy said: "We had to pour away three brews for today, Thursday and next Monday because the night-time temperatures are currently at between 10C and 15C, which is far too warm."

The traditional methods used to make Cantillon beer are integral to its taste - cooling the wort artificially would completely change the finished product.

"I adapt because I don't have any option, but obviously it's a shame." <p>Jean Van Roy, Cantillon brewer</p>

And because the beer needs to be air-cooled, the brewing season where the air is the right temperature is getting shorter every year.

Van Roy said: "Climate change has been notable in the last 20 years."

"My grandfather 50 years ago brewed from mid-October until May, but I've never done that in my life, and I am in my 15th season."

"Last year we didn't start until November 10," he said, saying they never go past the end of March as the temperatures get too high.

"I adapt because I don't have any option, but obviously it's a shame."

Van Roy says he is now worried for the brewery's future - and this year, he and his team will have to rush to produce their usual yearly outturn of around 400,000 bottles before the weather gets warmer and brewing season finishes.