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Ray Bittikofer

Cooking Water Treatment: Maximize the Life and Performance of Commercial Steamers and Combi Ovens

Maximize the Life of your Commercial Steam Equipment

Steamers and combi ovens are some of the most versatile and effective tools in a commercial kitchen. They allow for the preparation of meals using multiple techniques, save on time and deliver dishes that delight customers at every turn.

Yet there are unique challenges to working with steam that have the potential to wreak havoc on your equipment – leading to costly repairs or replacements if the damage is too great. The culprit? The very water that is used to give these devices the characteristics so appreciated in the restaurant industry.

The U.S. Department of the Interior’s geological survey defines water hardness simply as the calcium and magnesium dissolved into water. Hard water, also known as limescale, has high levels of dissolved minerals – which ultimately impacts steam equipment at every level. Based on your water source, the experience with hard water could range from a major issue with water hardness to a minor inconvenience. In any case, it’s important to address water hardness to prevent unnecessary expenses and impact on food production.

Damage to equipment due to poor water quality, inadequate water filtration and lack of proactive operator preventative maintenance are the most common sources of repair to commercial steamers and combi ovens.

Water Hardness Basics

Water hardness or limescale is a common issue, regardless of whether you’re using public water supplies or private well water. Limescale is the chalky white residue found at the bottom of pots, pans and inside steamers and their components after water has boiled off.

This residue is typically composed of calcium carbonate and magnesium that is left behind after the water evaporates. They are almost always present in the potable water and are generally not dangerous to consume.

However, because steamers in your kitchen use steam to cook food, inadequately treated water can become a menace. Typically tucked away from the naked eye, limescale can cause real damage to your equipment. In severe cases, the mineral deposits can form rock-like compounds in your steamer – impacting performance.

Impact on Equipment

The impact on your equipment is significant. These impacts can result in inefficient production from your steamers and combi ovens, leading to costly repairs – causing downtime for much-needed equipment. Worst of all, it only takes a few months for limescale to build up and damage your steam equipment.

Here’s a look at some of the major impacts limescale can have on your steam equipment.

For steam equipment with generators, limescale and other deposits can accumulate when the water exits the tank - leaving hardened mineral deposits behind in the generator. These deposits can coat the probes and elements, causing them to build up, forming a rock-like coating. In addition, these water treatment agents and minerals can corrode stainless steel, especially when it’s heated to high temperatures. Additionally, if left untreated – limescale can clog drains, restricting their use.

On heating elements, the limescale buildup creates insulation that both reduces the efficacy and shortens the lifespan of the parts.

Boilerless steamers and combi ovens can also be affected. The spray jets that play a vital part in creating the steam can become clogged and the heating plate or wheel can become coated with limescale. If left untreated, the unit can be extremely difficult to clean.

Fortunately, it’s easy to measure the hardness levels of your water to determine which preventative steps to take.

Water hardness is measured in grains. One grain per gallon equals 17.1 parts per million. Water hardness varies across the United States and is often characterized as follows:

  • Slightly Hard Water – 1-3.5 grains per gallon
  • Moderately Hard Water – 3.5-7 grains per gallon
  • Hard Water – 7-10.5 grains per gallon
  • Very Hard Water – More than 10.5 grains per gallon

Chemicals and Water Purity

Water hardness is just one factor to consider when it comes to keeping your restaurant systems protected. The other is the use of chemicals that cities and towns add to their water supplies to purify the water.

These chemicals can also add to the deposits that cause scale and make commercial water filters for restaurants a must-have. Here’s a closer look at these chemical additives and other naturally occurring elements that can impact your commercial equipment.


Chloride is a naturally occurring element present in water supplies. However, the compound becomes very corrosive when it’s heated above 140 degrees. That corrosion can penetrate the protective film that’s present on stainless steel, leading to destructive and swift damage to your critical food equipment. Even low levels of chloride can damage a combi-oven or steamer. They cannot be removed through basic filtration or softening processes.

Chlorine and Chloramine

Water municipalities often add a combination of chlorine and chloramine (free and total chlorine) to public water supplies to sanitize the water. The additives, however, can have multiple effects on your operation. In addition to being corrosive to stainless steel equipment in your kitchen, they produce a nasty smell and taste if used at high levels.

These sanitizing elements must be filtered out of the water being used in your steamer or combi oven. Chlorine, which is the most common water sanitizer, can be filtered out with an activated carbon filter. Chloramine, which is a mixture of chlorine and ammonia, has become more commonly used in recent years. It is a bit more challenging to filter out but can be removed using a carbon filter.


Iron deposits are common in municipal water supplies. They can leave deposits that oxidize quickly, leading to rust on the interior nooks and crannies of equipment.

The other elements at play are measured in total dissolved solids (TDS). The minerals can wreak havoc on stainless steel, reducing the lifespan and efficacy of your equipment. To maintain the integrity of the stainless steel, manufacturers increasingly publish acceptable water supply standards that can be checked to safeguard equipment investments.

Service calls to repair this equipment often are expensive. In addition, if the water supply being used does not meet the specified water supply standards, warranty service calls may not be covered or warranties may be voided altogether.

Vulcan, for example, recommends that hardness levels do not exceed 3 grains, that chlorine levels not exceed 30 parts per million and that the water’s pH level is between 7 and 8.

Water Filters for Commercial Kitchens

Fortunately, there are many kitchen water filtration system solutions available that can be used to prevent the damage from water hardness and other deposits. These solutions run the gamut and can be selected based on the severity of the water hardness levels and budget. No matter which water filtration is chosen, you want an option that will be most effective for your water composition.

Here is a look at three of the most common types of commercial water filters.

Template Assisted Crystallization Systems

This new form of water softening takes hard water and passes it through a small tank, converting calcium and magnesium minerals present into their crystallized forms. In crystal forms, the minerals cannot damage equipment. This process can be done quickly and requires little to no maintenance of the tanks where the process occurs. It also is a chemical-free procedure that inhibits the formation of damaging scale. The main disadvantage is that the crystallized minerals need to be removed.

Carbon Filter Systems

Carbon is a porous material that can absorb impurities as water passes through it. In these point-of-entry systems, water runs through the carbon filter, which can remove chlorine and chlorine byproducts, along with lead, PCBs, radon, pesticides and herbicides, other types of bacteria and traces of pharmaceuticals. Carbon filters, which are used in manufacturing and medicine, are an effective way to remove not only the minerals and elements that cause buildup, but other nasty components of your water.

Reverse Osmosis Systems

A common solution for a commercial water filtration system is to combine carbon filtration with reverse osmosis. The latter process forces water through a semipermeable membrane that acts as an extremely fine filter. These systems remove more fine impurities that may get through carbon filters, such as TDS, chlorides and other common water impurities.

Sediment and Carbon Block Filter with Scale Prevention

Vulcan's ScaleBlocker® is recommended for steamers to help minimize limescale buildup and corrosion, which can dramatically impact the operation of your steamer and result in downtime or service calls. It’s a safe and economical way to maintain your Vulcan Steam Equipment.

No matter what solution you use, the key is to know what the composition is of the water used in your kitchen and in your equipment. Then you can refer to manufacturer recommendations to identify the levels you want to achieve and purchase the right filtration solution for your establishment.

ALWAYS Remember To:

  • Test your water
  • Install an appropriate water treatment system
  • Maintain equipment with proper cleaning, deliming and preventative maintenance

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