Steam Water Spray retorts: 30 years of U.S. sterilization excellence

Developed in Spain in the 1980s and later introduced to America for military purposes, Surdry SWS batch retorts remain the top choice for efficient and sustainable operations. 

Most food and beverage manufacturers are familiar with the benefits of Steam Water Spray (SWS) retorts in the sterilization process. SWS technology combines bottom heating by direct steam injection with superheated water spray from the top and sides, ensuring uniform heat distribution in a short time. It also allows the water used in heating to be reused in the cooling process, making it a sustainable and cost-effective option for manufacturers. 

How was this solution created?   

In the 1980s, new food packaging alternatives to traditional metal and glass containers emerged, including flexible pouches made from multilayer plastic and aluminum films.  However, processing these new pouches in standard retorts was challenging: the technology designed for cans did not suit the flexible nature of pouches. Saturated Steam (SST) retorts couldn’t handle the pressure generated inside the pouches, causing them to swell and burst.  Water immersion also proved unsuitable due to issues with pressure, temperature balance and excessive water and steam consumption. To overcome these challenges, Surdry developed the SWS retorts, a system that remains the optimal solution for flexible packaging today.   
 

How did these Spanish retorts make their way to the U.S.?  
 
During the Gulf War, there was an urgent need to increase military rations for troops in conflict areas. In 1991, Surdry produced the first SWS retorts for the U.S., specifically for a copacker tasked with producing military rations. The retort process ensured that the food shipped had an extended shelf life. Surdry’s retorts were essential for sterilizing the rations in flexible packaging, which were lighter and more space-efficient than conventional glass or metal cans, making them easier to transport worldwide.   

Thirty-three years later, many of those pioneering retorts are still in operation, with several hundred more having followed in their footsteps.  

To learn more about Surdry SWS retorts, click here or contact us at sna@surdry.com.