The increasing appetite for Greek yogurt among consumers worldwide has made the product one of the fastest-growing trends in the food industry. In 2017, the world market for this taste-intensive strained yogurt was worth around US $ 50 billion – and growing. People love the thick and creamy texture, which is achieved by straining and ensures less water and more protein content. Greek yogurt and its Greek-style counterpart are conquering refrigerated food shelves around the globe. However, Greek and Greek-style are two different products, not just in terms of geography, but also the recipe and production method. Inspired by the thriving export business for Greek yogurt, Greek dairy Kri Kri has invested heavily in increasing production to meet demand. The company was building a new production line at its Serres site and required two heat exchangers – one to heat up coagulated milk from storage temperature to straining temperature and the second to cool it back down to storage temperature.
Nikos Safis from contractor European Food Systems Ltd proposed using a separator, instead of the ultrafiltration method, for straining the yogurt. However, the challenge was that the product coming out of the separator needed very careful handling, with minimum stress to achieve the desired smooth texture. Too much mechanical stress causes whey to collect on the yogurt surface. The answer was a heat exchange solution that combined low velocity with low pressure. Kelvion’s extensive know-how in food applications meant we had the ideal candidate in the NL80 heat exchanger. With conventional plates, low velocity reduces the performance, leading to a build-up of deposits on the surface. But the NL series, with its OptiWave plate design, developed by our R&D team, offers an outstanding interaction of the plate profile and corrugation depth. It ensures high heat transfer rates by means of uniform distribution of the product over the entire width of the plate. Originally Kri Kri was going to acquire heat exchange equipment from a competitor but Nikos was able to demonstrate the superior performance of the NL80. Following tests on the product line we added extra plates to ensure the optimum low velocity and pressure drop. Our units have been operating successfully since they were installed in 2016. Kri Kri is so satisfied with the result that it is expanding production and has ordered two more heat exchangers.
Dimitris Barmpoutis, Head of Production at Kri Kri, says: “One of the main reasons we chose the Kelvion heat exchangers is that they were proposed by GEA as a complete solution, along with the new separator line. Obviously their specialized design would improve and ensure gentle product handling during heat treatment. Hygienic standards of the PHE were also carefully assessed and evaluated as the whole straining process can be very sensitive. Finally we decided to follow the same ‘recipe’ for our second GEA straining line as aftersales support from GEA Hellas and Kelvion were up to the Dairy Business high standards.” The combination of separators and Kelvion NL80 heat exchangers is now becoming the benchmark for Greek yogurt production. “It is a complete approach that guarantees as smooth a process as possible,” says Nikos. “Other dairies are now following our recommendations.” So far 18 installations have been completed in other Greek yogurt production sites in Greece and also a Greek-style yogurt plant in Romania.
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