The Challenges Facing Low-Acid Beverages

In response to more competition for retail space, many beverage entrepreneurs are considering bringing low-acid, shelf stable, ready-to-drink (RTD) beverages to the market. Starting a beverage company is challenging enough, but if you’re considering launching a low-acid, shelf-stable beverage like a RTD coffee, canned protein beverage, or some canned teas, it’s vital to understand the added challenges you could face when it comes to preservation. 

The Importance of Preservation

Preservation is the process of treating a beverage to stop or slow down spoilage and loss of quality, and to extend shelf life. There are certain microorganisms that may cause spoilage or illness that can survive in a low acid environment that are less likely to survive in a high-acid environment, alcohol, or carbonated beverages. All of those factors are accounted for in the required processes and preservation methods for beverages. 

The goal when preserving your beverage is to find the best possible way to prevent the growth of bacteria and other microorganisms while maintaining the quality and nutritional value of the beverage. The preservation method required for your beverage will depend on multiple factors including desired ingredients, pH, packaging, and the co-packer’s capabilities. During the commercial formulation process, your formulator will work with you to determine the best method for your beverage. It is also important to consult with a processing authority, who has expert knowledge of thermal processing requirements for low-acid foods and beverages packaged in hermetically sealed containers. Some popular beverage preservation methods include tunnel pasteurization, hot filling, flash pasteurization, aseptic filling, high pressure processing, chemical compounds and velcorin. 

Thermal Processing

Temperature is the most common method to control bacteria, and a variety of time/temperature combinations are used. Preserving low-acid beverages, with a pH greater than 4.6, and a water activity greater than 0.85 (as defined by the FDA), without refrigeration is especially difficult as these beverages are subject to special legislation requiring them to undergo processes that are certified to kill all viable forms of microorganisms of public health significance, as well as any microorganisms of non-health significance capable of reproducing under normal storage conditions. Hot fill, retort, tunnel pasteurization, and UHT beverages that are aseptically filled  are examples of thermal processes that sterilize the product and allow it to be shelf-stable at room temperature. 

Retort processing can make a low-acid beverage shelf-stable, but it carries some significant challenges that need to be addressed in the early stages of planning and development. 

Retort 101

Retort processing is not new. It was Invented in 1874 by A. K. Shriver, who worked in a Baltimore oyster and produce plant. Although there have been advances in technology and equipment, the process has essentially remained the same. The goal of the retort process is to preserve the quality and safety of low-acid products with pH levels between 4.0 and 7.0 without using preservatives. Retort sterilizes beverages after they are sealed in a container by steam or other heating methods. Sterilization temperatures typically range from 245°F (118°C) to 255°F (124°C) and depend on the slowest heating part of the beverage, known as the cold spot. 

Products with a high risk for pathogens and microorganisms require retort. The thermal process kills microorganisms, like clostridium botulinum, that cause spoilage and pose a public health risk under normal storage conditions.  The longer and hotter the treatment, the more shelf-stable the beverage becomes. Beverages sold in the United States are required to comply with Federal regulations relating to the processing of low-acid foods packaged in hermetically sealed containers. 

Retort can be applied in a batch sterilization process, making it faster and less costly than other methods of sterilization, such as aseptic filling. While retort is a proven, effective method for preserving shelf-stable beverages, there are a few important considerations to keep in mind when pursuing a beverage idea that requires retort. 

Question 1: Can your product, process, and package stand the heat?  

Retorting requires that your beverage and packaging undergo a required temperature for an adequate amount of time to sterilize them. Heat affects the quality of the finished product and puts constraints on your processes. Product safety comes first and will impact options for your product formulation, equipment, and packaging. 

Achieving safety and quality throughout the retort process requires knowledge, skill, and usually some trial and error. You have to determine not only the right amount of heat needed to kill specific organisms, but also how different stabilizers and ingredients will react individually and together to maintain the desired flavor, color, consistency, and shelf-life of the end product. 

Liquids and packages conduct heat differently depending on various qualities like viscosity, shape, size, and headspace. Some gums and stabilizers might change consistency over time after being exposed to heat. The added complexity of retort processing makes the already challenging beverage formulation process even more tedious and time-consuming. It is essential to work with formulators who understand retort and to build in the time and budget you need for development. 

Question 2: Can you find a contract packer?

Retort processing equipment is expensive and in increasingly high demand. Large companies like Pepsi (which owns Starbucks RTD Beverages) have taken over much of the available retort processing capacity. Consolidation in the co-packing market means there are fewer independent facilities, and larger contracts with higher minimums are winning out over smaller projects. 

You have to be prepared to sell yourself and your idea to be in the running for retort line time. Co-packers want to maximize their capacity and would rather increase production with existing or high-potential customers than incur the cost and risk of working with new, unproven entrants. There are only a few facilities at any given time that are accepting new retort customers, and the competition for those spots is fierce. 

A Realistic Approach To Retort 

These considerations shouldn’t steer you away from pursuing a project that would potentially involve retort. Instead, these questions will help you approach the opportunity with more clarity and control.  Knowledge is power in the world of beverage development and production. The goal is to maximize your resources, using knowledge and data to make the best decision at every stage of the process.