When looking at the distinction between batch fryers versus continuous fryers in potato processing lines, the arguments often revolve around the overall amount of frying oil in the entire frying system compared to yield.

“Normal continuous potato chips fryers have an Oil-Turn-Over-Rate of less than eight hours whereas, in a traditional batch fryer, it can reach 35 – 40 hours. The Oil-Turn-Over-Rate is defined in hours and calculated as the weight of the vegetable oil in the frying system divided by the weight of oil pick-up in the chips per hour. The longer Turn-Over-Rate, the higher risk for the frying oil to get rancid,” Rosenqvists experts explained.

Protecting the vegetable oil in a batch fryer is more difficult because it will not be covered by a steam protection layer during the final two minutes of frying. After all, the frying time is typically five to seven minutes and the water inside the potato slices is evaporated during the first two minutes.

“Most batch fryers are heated by gas. The gas is fired in tubes placed inside the frying pan. The open flames inside the tubes are heating the oil. The flame temperature from the gas can be very high, perhaps even as high as 800–900 degrees Celsius. If the tube system is not properly designed, the heat penetration onto the oil will be too high, resulting in hot-spots film and uneven temperatures causing the vegetable oil to break down faster,” the engineers added.

Direct gas-heated fryers are suitable for capacities of up to 150-160 kg/h of finished potato chips. However, for higher capacities (250-300 kg/h), an alternative heating source is recommended to minimize total oil volume and allow for additional technical solutions to the aforementioned issues. This is because the total amount of vegetable oil in the batch fryer system is critical.

One of Rosenqvists Food Technologies’ solutions is the patented dual-function fryer. A fryer for true batch fried chips and normal potato chips. All in the same pan.

According to company experts, the market has seen a growing interest in batch-fried chips over the last 7-8 years. So the company designed a pan that has two different systems inside its hood, which can be switched. Each one has the required elements needed to transform the fryer between continuous and batch-style production.

You can read the rest of this article in your complimentary e-copy of Issue 2 of Potato Business Dossier 2023, which you can access by clicking here.