The deep end
Deep-fried food may never win votes from the calorie-counters, but it continues to produce healthy profits in most branches of catering. Yet kitchens that readily spend £5,000 or more on a combi-steamer often try to get by with inadequate fryers costing just a few hundred pounds.
A lot of the shortcomings of fryers are simply due to their design. These include:
Lack of power. In peak periods delays occur because the fry-tank heater can't return the oil to the correct frying temperature fast enough. This causes delays in service and staff are tempted to serve insufficiently cooked food.
No temperature control other than a single thermostat pre-set to frying temperature. If this fails, which is not uncommon, there is nothing to stop the oil overheating - a serious fire risk if the fryer is left unattended.
No cool zone provision in the base of the tank to allow burnt food particles to separate. This results in reduced food quality.
No drain valve fitted in the base of the fry-tank, making it difficult to empty the oil for filtering and tank cleaning. The tank therefore rarely gets cleaned and the oil or fat gets stale and clogged with burnt food debris.
Reluctance to invest in such basic provisions on deep-fat fryers is a false economy. After all, frying is one of the most dangerous jobs in the kitchen, particularly when done by relatively inexperienced staff.
Peter Martin, staff catering controller at Tesco, says the reliability and performance of equipment is ultimately down to staff training. He ensures that chefs at Tesco's 400-plus staff catering kitchens operate frying equipment as consistently as possible.
Stipulations for the Falcon fryers used across the chain have included accurate temperature read-out via liquid crystal displays and cut-outs to prevent oil overheating should the main control malfunction. One feature that was developed especially for Tesco is a pressure pad sensor in each tank that prevents the fryers from heating up if they do not contain oil. The chain found that staff were switching on fryers that had been drained the night before, filling the kitchens with smoke and in some cases causing the residual oil in the tank base to ignite. About 15 fires occurred this way.
The special modification overrides the "on" switch, forcing the operator to go through a resetting procedure and top-up the oil to the correct level.
Another special feature of the fryers is their configuration as complete frying stations. Shielded on three sides, with an ambient section in-between two fryers, makes the set-up more convenient for handling food.
Oil is kept cleaner by a built-in cool zone in the fry-tank of the fryers. Burnt particles from the food drop into the cooler oil below the heating elements, rather than sticking to the food and causing oil deterioration.
The latest fryers on the market now have fast-acting electronic thermostats - said to give more control and lower oil consumption than standard thermostats - as well as overriding safety thermostats with automatic cut-out.
Martin has looked at further fryer refinements such as computer-controlled basket lift, and the use of separate filter machines to draw oil from fryer-tanks, filter it and pump it back. Of these he says: "Frankly, they don't make a lot of difference. You still have the task of cleaning the fryer. In fact, using a filter machine entails the extra cost of maintaining the machine as well as needing extra space."
The Royal Burnham Yacht Club at Burnham-on-Crouch, Essex, last year invested in a new Ofcar double- pan fryer that takes a different approach to keeping the oil clean. The Italian-made unit has a deep cool zone section in the base of each tank, but instead of containing oil it is filled with six litres of water. About 20 litres of cold frying oil is then poured in, which floats in a separate layer above the water.
The water is well below the base of the electric elements and stays much cooler than the oil in a conventional cool zone. The aim is to trap particles from the food and reduce stirring up the debris that occurs when an ordinary fry-tank is heated up.
Does it really work? "It's a very clever idea," says Mike Shields, managing director of Shields Catering, which is franchised to handle catering at the club. He estimates the system enables the oil to last four to five times longer than it did in the gas-fired deep-fat fryer previously used.
The fryer is also much easier to look after, he says, and needs only a once-a-week clean-through. This is accomplished by draining off the cool oil via the upper valve provided. It can then be strained and re-used. The water is drained from its section of the tank via a separate, lower valve, and discarded.
Economic sense
Shields finds that a small amount of oil drains away with the water but, despite this, the unusual tank design makes for much more economical oil usage.
The only snag is an occasional "bubbling up" effect that has occurred during a busy session, presumably because water mixes with the oil and escapes upwards. Shields suspects that it happens when the oil has not been given sufficient time to recover its correct temperature before a new batch of frozen chips is added.
Nobody has been burnt but the consequent splash-out effect is disconcerting for staff and means the fryer is turned off for a time to settle down. The fryer's supplier Elmwood Equipment has checked and reset the thermostats and maintains that, as long as the instructions are followed and a sufficient recovery period is allowed, the problem should not recur. Current list prices are £1,380 for a single-bowl model and £2,325 for a double-bowl.
A water base fryer is used at Brocket Hall, a stately home near Hatfield in Hertfordshire, that is now a golf club and corporate entertaining venue. It is supplied by Hobart as part of a complete Comby Chef bespoke island cooking range.
Mark Gregory, who operates the catering at Brocket Hall, finds that oil temperature recovery is exceptionally fast and has experienced no "bubbling-up" problems. His fryer uses baskets with solid sides and a mesh base, which he finds help to concentrate the heat during frying operations.
For some caterers, environmental restraints rather than operational make frying difficult. For Corney and Barrow Restaurants, which runs a chain of wine bars in the City of London, cramped premises - often basements - in old buildings have made conventional deep-fat frying impractical because of the fumes, smell and heat generated in a confined space.
Despite this, all but two of the chain's 10 wine bars have a range of fried foods such as Cajun shrimps, Japanese prawns, chicken goujons and hot jalapeno peppers. These are deep-fried in hot oil in the usual way but within a compact enclosed counter-top fryer unit called an Autofry. Each is fully self-contained with its own three-layer fume filtering system comprising a steel baffle, mesh filter and carbon filter. The units can operate in a ventless area with clean air coming out of the machine.
"They prevent the smell of oil getting into the bars," says Catherine Felgate, Corney and Barrow's operations manager. "Quite simply, we would not be able to do any frying without them."
The Autofry units cost about £5,000 each, many more times the price of a conventional deep-fryer of comparable output - but Felgate says they have an "extremely user-friendly" design.
Staff simply pour a pre-measured portion of food through a chute into the fry-basket and set a timer switch. After cooking, the portion is tipped out automatically from the fry basket on to a plate and served.
Cleaning involves passing the oil in the tank through a Miroil filter every three days or so. The two metal air filters are put in the dishwasher each day after the fryer is switched off and stripped for cleaning. The carbon filter is checked every month as part of six-month service carried out by supplier Servequip.
Demands on staff
The Autofry, which is sold in staff-operated and customer-operated versions, is one of several new enclosed fryers targeted at applications where open frying tends to be difficult or impose too many demands on staff.
One stage on from this is the oil-less fryer - an enclosed counter-top unit with automatic control that dispenses with the need for a deep-frying tank.
Batches of food, preferably prepared to a par-fried specification, are placed in a mesh-sided drum that is kept constantly rotating within a stream of hot air.
The oil-less frying idea has been around in various forms since the 1970s, without notable success. But some of the latest models, such as the Rofry and the Eloma AirFrit, offer control improvements aimed at maximising energy.
