Steam is used in food processing for a variety of reasons — from preparing product to cleaning equipment. Common uses of steam in food and beverage facilities include:
- Blanching product
- Rehydrating product
- Sterilizing equipment
- Steam-in-Place (SIP) to clean pipes
But not all steam is created equal.
The 3 Types of Steam in Food Processing
Steam used by food processors commonly falls into three broad categories:
- Plant steam — Sometimes called utility steam, this type of steam is typically produced by a boiler and can be used in applications that do not involve contact with food product or with surfaces that contact food products (e.g., indirect heating).
- Culinary steam — This is steam used for direct injection into product or to clean or sterilize product contact surfaces. Culinary steam typically contains additives that prevent corrosion and scaling within boilers, so it is often filtered before coming into contact with food product. Any additives in culinary steam must meet all applicable FDA and USDA requirements for human consumption.
- Pure (or hygienic) steam — Pure steam does not contain any additives and is created by heating untreated water that is stored separately. Pure steam is often used to produce organic products that restrict usage of chemicals and additives.
It’s pretty clear when and how you should use ordinary plant steam, but when it comes to food contact, what steam should you use: culinary or pure? The majority of the steam used in the food industry is culinary steam, but there are instances in which pure steam is preferred or required.
Let’s examine the benefits and considerations that come with each.
Culinary Steam Vs. Pure Steam: Benefits and Considerations
Culinary steam is the standard in most food plants. It is food safe and can be used to blanch, rehydrate and sterilize food product. More than likely, culinary steam is the appropriate choice for your facility, but there are some considerations to keep in mind.
Benefits of culinary steam
- More economical in the long-term — Compared to producing pure steam, culinary steam requires less energy and water, meaning lower utility bills in the long run.
- Less costly upfront — Opting for culinary steam doesn’t require the big initial investment in a steam generator, saving you money upfront.
Considerations with culinary steam
- Not as hygienic — While culinary steam is food safe, it’s simply not going to be as hygienic as pure steam that doesn’t contain any chemicals or additives.
- Ongoing cost and maintenance — Since culinary steam is made from water containing additives, the steam is run through strainers and filters to remove as many of the impurities as possible before it is introduced to the product. These filters must be changed on a regular schedule; if they are neglected, an inspector can judge your steam quality below the requirements to be classified as culinary steam.
Pure steam — sometimes called hygienic or “clean” steam — is the most food-safe option available to food processors. Typically, processors who use pure steam are doing so to meet organic food standards.
There are two ways to produce pure steam:
- Steam heating coil — This method involves utilizing steam from the plant boiler to heat coils that in turn heat the water they are submerged in. Much like boiling a pot of water on a stove, this container of water is heated until it changes phases and creates steam. Since the container is exposed to the atmosphere, not all of the steam can be contained, making this method somewhat inefficient. Plus, excess steam that escapes will eventually raise the humidity level in the building, which can create other issues like mold or bacterial growth and/or equipment rusting. This can be mitigated by properly venting the space where the system is located.
- Steam generator — This method also involves heating a container with coils, but the water is contained in a sealed, pressurized tank rather than being open to the air. This is more efficient than a steam heating coil since the steam is contained and can’t escape.
Benefits of pure steam
- Increased food safety — Using pure steam improves the hygienic quality of your products and is as food safe as you can get when it comes to blanching and other steam-related processes. There is no risk of any chemical contamination because there are no additives in the water to begin with.
- Meet organic food standards — The majority of food processors that utilize pure steam do so to meet certain standards in order to label their products as “organic.” There are various ways to define and label food as organic, and each definition comes with its own standards. Since most organic foods require no introduction of chemicals or additives in processing, this almost always means pure steam must be used.
Considerations with pure steam
- Less efficient — Generating pure steam requires additional water and more electricity to heat the coils and power the process. This means increased usage and higher utility costs long-term.
- More expensive upfront — Complex equipment like steam generators are a big investment. While traditional culinary systems come with startup costs (pipes, strainers, valves, filters), it’s usually not as expensive as opting for a pure steam system.
Something else to consider is that choosing pure steam it isn’t an “all-or-nothing” decision. A facility can have several blanchers but only elect for a few to be equipped with pure steam capabilities. This allows plant owners to have flexibility in deciding how much money to invest based on their needs and organic SKU percentage.
How much pure steam capability you need — or whether you utilize pure steam at all — really depends on how much organic product you produce, if any. An experienced partner can help you make the best decision and calculate the right balance for your facility’s needs.
Stellar is a fully integrated firm focused on planning, design, pre-construction, construction, refrigeration, mechanical & utility, building envelope, and total operations & maintenance services worldwide. Visit the company's blog at www.stellarfoodforthought.net or learn about its projects at stellar.net.