Fancy a beer with a side of innovation? That's what Charlie and George are offering, two mates who got together five years ago to start Crossover Blendery in Weston, North Hertfordshire.

Their beers take more than three years to make, compared to normal beer that takes just two weeks.

It's all to do with the method they use to make their drinks, described as 'spontaneous fermentation'. Traditionally, brewers will add yeast cultivated in a lab to turn sugar into alcohol. But Crossover instead rely on yeast that is naturally present in the air.

They're one of few UK blenderies making beer in this way. Charlie tells me that many others making barrel-aged beers use mixed fermentation, "mimicking our style but over a short period of time by adding in a mixed culture".

"We don't think that gives you the same level of complexity and depth as our beers."

In comparison to a normal beer, Crossover's drinks "get a bit acidic from the barrels - they taste more towards a cider or a natural wine, and we often add fruit to them too".

From their base at Lannock Manor Farm, their beer is aged in old burgundy wine casks made of French oak, and stored in an old grain store full of barrels.

It isn't just wine casks they use, but casks that previously contained spirits such as whiskey, tequila, cognac, and gin, which all enable Crossover to extract different flavours from their beers.

This year, they've blended about 1,000 litres of 35 different beers, with a constant rotation of drinks available for sale in small batches.

They're similar to wine vintages, in that each year will be slightly different based on variables such as the temperature and the growing conditions for the fruit they use.

Getting to this position has been a "labour of love", says Charlie, given the lengthy fermentation times involved in their process.

"Previously, we were having to sell the beers after only 9-12 months, and working part-time alongside that.

"George was working in a beer shop in Hitchin, I was tutoring.

"We just needed cash flow. The drinks tasted fine, but completely different to how they are now.

"Starting shortly before Covid hit wasn't ideal timing. We had to build a presence on Instagram, documenting what we've been up to, and thankfully people took an interest from there.

"When we launched our first few beers, they sold out completely through Instagram sales. Without that platform, it would have been very difficult."

Now, they've been able to take advantage of a number of different channels to sell their product. They sell directly through their website and at an on-site taproom, as well as to beer shops, farm shops, pubs and restaurants across the UK - including some with Michelin star tasting menus.

Their customers aren't just in the UK either - Charlie says they ship all over Europe, to the USA, and even to several Asian countries.

How did they get the idea for the business?

Charlie says: "When George and me we were at university together, we went to Cantillon in Belgium, one of the best regarded breweries in the world.

"Just by chance, a dad of a friend of ours used to drink lambic beers when we were younger, so we were already familiar with the style.

"And sitting in their taproom, we decided to go ahead and set up our own blendery."

Even after Covid, things have been tough, with price rises and shortages of raw materials.

"It's been constant, and there are still problems now. We've been going into a headwind through it all, but we're still going.

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"It's come with a lot of mistakes. It's a very hard style of beer to make given the time involved, but we've now hit that three-year period with a good amount of stock coming through and have been able to refine the process too."

Their beers are "99 per cent British", with only cinnamon and Madagascan vanilla imported from abroad. Otherwise, they rely on British suppliers and small farms to supply them the best fruit possible, with plums from Cam Valley Orchards near Royston, apricots from the Isle of Wight, and berries from Herefordshire.

They've also used some wheat from the very farm on which they're based - with fruit trees now planted there too in the hope that their produce can be put into the beers when ready.

The taproom at Crossover Blendery is open all summer, from 5pm to 10pm on Fridays, midday until 8pm on Saturdays, and midday until 5pm on Sundays.