Crop Drying Case Study - Barton Place Farms

One of the UK’s leading onion producers has boosted production and ensured a quality crop – with the support of Calor.

Barton Place Farms, near Bury St Edmunds, provides 4,000 tonnes of onions to pre-packers in East Anglia who supply leading multiples. Of the 2,000 acres on the mixed arable farm, 400 acres are used to grow a wide range of onion varieties, including spring sets and varieties such as Samira and Hyfield, as well as red onions.

Owner Peter Hay prides himself on growing a quality product. ‘We’re producing British food for the British consumer, grown to high environmental standards,’ he says. ‘Quality is central to our operation and although we’re a high volume producer we’re committed to supplying the consumer with a good tasting product, grown responsibly.’

The farms’ produce primarily ends up on the shelves of leading supermarkets, creating particular requirements. ‘It’s easy to knock the supermarkets, but they do buy a huge amount of British fruit and vegetables,’ adds Peter. ‘That’s the market we’re in and we meet their demands by delivering the best quality produce we can grow.’

 

Recently, the operation was expanded following the purchase of additional farmland and an adjacent contract farm, meaning, says Peter Hay, an increase in the tonnage of the onion crop and the required drying capacity. ‘We took the decision to build a new multi-use store and, as we faced a tight timescale before the new season, it was vital that we had the right advice,’ he adds.

Peter turned to Suffolk based Thurlow Nunn Standen, which specialises in the specification, installation and project management of grain, onion and potato storage projects. ‘We’ve worked with Barton Place Farms for many years,’ says the company’s Jeremy Nunn. ‘We’d previously supplied a 1,000 tonne bulk and an 800 tonne box onion store, as well as a grain drying facility. The site had an existing burner capacity of up to 13 million Btu,’ he adds. ‘We could see that expanding the operation would require working with an expert LPG supplier and that’s why we worked with Calor.’

A new 2,000 tonne capacity shed was specified, with a drying system comprising three Matthews and Yates air drying and circulation fans in a triplex set, with three Octagon Products burners, giving an additional combined heat output of 6.75 million Btu. A Farm Electronics automated control system was installed to monitor and to provide accurate temperature and humidity.

 

Calor’s Jeff Penfold worked as part of the project team, discussing Barton Place Farms’ LPG requirements and recommending the optimum solution. ‘The key issue was to balance the gas supply so that existing applications would continue to receive the required gas load, as well as powering the new equipment,’ he says. ‘In addition, the onion season lasts for only six weeks, with large amounts of gas being used, so the farm required reliable quantities of gas at specific times of the year. Our aim was therefore to provide a solution that ensured a reliable gas supply across the site.’

Barton Place Farms already had two 12 tonne Calor tanks installed and the new onion drying facility would effectively double the gas usage. Calor’s technical team, in addition to allocating frequent Calor deliveries throughout the drying season, specified a new vaporiser that ensures the required gas volume and pressure can be delivered from the existing tanks. ‘We specified the vaporiser, at an additional charge and with Peter Hay’s agreement, to make sure that need was met,’ says Jeff. ‘It’s an illustration of how Calor finds the right solution for each customer’s requirements.’

 

Crop drying is integral to Barton Place Farms’ business. From the start of the onion harvest, the five drying sheds are powered by Calor to deliver the required finish. ‘It’s our response to people’s change in buying habits,’ says Peter Hay. ‘Shoppers have become accustomed to seeing English onions as golden skinned. Drying on Calor LPG allows us to seal the necks and produce the dry, golden effect that’s required, as well as maintaining precise control of the drying process.’

Harvesting and drying the onion crop is in two stages. From August onwards, the onions are topped in the field and lifted onto the surface to be wind dried for 24 hours before transportation to the drying sheds.

First the onions are inspected to remove stones and other extraneous material, then graded and dried for 48 hours at a constant 28oC to dry the skins and seal the necks. The crop is then loaded in the drying sheds in layers, to a maximum height of 4.3 metres.

The second stage of drying sees the onions cured for up to a four week period at a lower, ambient temperature, producing a dry, golden skin. In this environment, the onion crop can be maintained at optimum quality for several months if required.

But it’s not just onion drying where Calor provides Barton Place Farm with the required energy solution. The farm’s drying sheds are also used for grain drying during the wheat harvest, and Calor LPG is also used to heat the workshop.

The entire project was delivered in 16 weeks, from initial consultation to commissioning on the agreed date in time for the new onion harvest. Peter Hay agrees that Calor’s expertise ensured the installation of an effective system. ‘Calor worked with us to iron out any problems and the system has worked well for two years now,’ he says. ‘We rely on Calor to provide us with the best solution for our business needs.’