4 Chemicals Commonly Used in a CIP Cycle

Four Chemicals Commonly Used in Clean-in-place Cycle

Clean-in-Place (CIP) is employed in hygienic processing industries where it’s essential to produce product that is pure and safe to use. Cleaning of hygienic process equipment used to be done by hand using labor-intensive practices that were difficult to repeat with precision. 

CIP technologies enable increased productivity because plants don’t have to shut down production in order to take systems apart for cleaning. Automated CIP also improves worker safety by eliminating some high-risk activities such as disassembling pressurized pipes that contain potentially harmful cleaning chemicals. 

Finally, pharmaceutical and biotechnology industries count on reliable, repeatable CIP processes that operators and auditors can validate.

In this article, we focus on the four chemicals commonly used in CIP cycles and how they achieve their results. But first, let’s start with a definition of CIP.

CIP is a method of cleaning

Clean-in-place accommodates cleaning without having to remove or disassemble piping or equipment.


Advantages of a CIP System:

  • Minimizes Mistakes: Automating cleaning reduces the chance of human error that can contribute to an unsafe product.
  • Keeps Employees Safe: Reduces chemical exposure by containing cleaning solutions within the system.
  • More Production Time: As less production time is lost to cleaning, more time is spent making product.
  • Product Quality: Reliable and repeatable cleaning means sustainable product quality and consistency. Less contamination means fewer product recalls and higher brand confidence.
  • Utility Savings: Water and energy usage is reduced through repeatable cycle control.

Importance of Using Chemicals in CIP Cycles

CIP Systems pump cleaning, rinsing, and sanitizing solutions through the same piping path as the product to eliminate product soil from all internal surfaces.

These chemicals include

  • Caustic
  • Acid
  • Sanitizer/Disinfectant
  • Sterilizer

Given the many variables that go into selecting the right chemicals for each CIP application, it is recommended you contact your CIP engineering partner to purchase chemicals that are right for your needs.

Below are more details on common CIP chemicals and general guidelines for their use. The right chemical cleaning agents in the right concentrations make a significant difference in the efficiency of your CIP system.

When used properly, CIP cleaning agents

  • Reduce surface tension of water, making it easier for the cleaning solution to penetrate soil
  • Break down bonding forces between soil and surface
  • Soften fats so they can be rinsed away
  • Dissolve soils for easier cleaning
  • Emulsify water-soluble soil in the cleaning solution for easier transport
Note: Without chemical additives most CIP systems still achieve a reasonable level of cleanliness and safety, but the time, action, and temperatures required to do it increase.

In manual CIP systems, operators often add more chemicals than needed to cleaning cycles. This overcompensating can be costly. Understanding the role chemicals play in your cleaning regimen, and adopting automation for dosing control and concentration monitoring, help to keep those costs in check.

1. Caustic

Also known as caustic soda, sodium hydroxide or NaOH. This is an alkali with a very high pH that is typically used in a concentration range of 0.5-2.0%. Concentrations as high as 4% may be used for highly soiled surfaces.

  • Typically used as the main detergent in most CIP wash cycles
  • Softens fats, making them easier to remove
  • Non-foaming formulation can help reduce pump cavitation and increase efficiency


2. Acid

Nitric acid is the most commonly used wash for scale removal and pH stabilization after a caustic wash. At a typical concentration of 0.5%, it can be used effectively at lower temperatures than caustic solutions, requiring less heating.

Phosphoric acid is sometimes used but is somewhat less common.

  • Used by dairies regularly to remove milk scale or “milk stone”
  • Excellent for brightening up discolored stainless steel by removing calcified mineral stains
  • Must be used with caution because they can attack some elastomers in the system like gaskets or valve seats causing premature degradation or failure
Tip: Acid wash should not precede a caustic wash when removing milk deposits as acid could cause protein precipitation thus making the deposits more difficult to remove

3. Sanitizer/Disinfectant

The job of a sanitizer, also referred to as a disinfectant, is to reduce microorganisms to a level where they don’t pose a risk to food safety or public health.

For many years various hypochlorite solutions (potassium, sodium or calcium), also known as “hypo,” have been used as sanitizers in many CIP cycles.

Their active ingredient is chlorine (bleach) so they

  • Are relatively inexpensive to use
  • Are very effective as a sanitizing rinse for soils that are prone to bacterial growth such as dairy products
  • Can be very harmful to stainless steel, causing staining, corrosion and pitting
  • Can cause some significant environmental problems when dissolved in wastewater streams by killing vital microorganisms in streams and waterways

Chlorine dioxide has been used as an alternative to hypochlorite solutions in cleaning applications with high organic loads such as poultry or fruit processing.

Chlorine dioxide

  • Has much more oxidizing power than bleach
  • Is less corrosive to equipment
  • Is less harmful to the environment

In recent years more sanitation managers have turned away from bleach-based sanitizers in favor of peracetic acid (PAA). A combination of hydrogen peroxide and acetic acid.

PAA is

  • A strong disinfectant even at low temperatures
  • Rinses away well leaving little or no chlorine residue to corrode stainless steel
  • Effective against all microorganisms including spoilage organisms, pathogens and bacterial spores
  • Also proven to be more eco-friendly in the wastewater stream
Peracetic acid has a strong, pungent odor, so it should only be used in well-ventilated areas.

Care should always be taken to rinse all sanitizers thoroughly from the system to reduce the risk of corroding stainless steel and potentially forming poisonous chlorine gas if mixed with acid.

It is possible to sanitize a system without using any chemicals at all with

  • Hot water (approx. 195 - 205° F for 15-20 minutes) or
  • Low-pressure steam

Both non-chemical options result in significantly higher energy costs and are relatively uncommon.

4. Sterilizer

Sterilizing a system means completely eliminating all living microorganisms. Sterilization can be done using chemicals but it is usually done with high pressure steam (approx. 250° F for 30 minutes).

While food, dairy and beverage processing plants seldom require sterilization in their CIP process, it is a common cleaning operation for pharmaceutical or extended shelf life (ESL) products.


Bonus Tips When Using Chemicals

1. Elevating the temperature of a cleaning solution increases its soil removal efficiency. The additional energy required to heat the solution adds cost to the process, but hot molecules with high kinetic energy dislodge soil faster than the slow-moving molecules in a cold solution.
2. A concentrated cleaning solution cleans a dirty surface better than a dilute solution. More chemicals mean more money, but the increased surface-binding capacity of a higher concentration cleans better and faster.
3. Longer periods of detergent contact exposure clean better than shorter periods of exposure. More time spent cleaning means less time making profitable product, but over time the chemicals dissolve hard soils from the surface.
4. Chemical solutions can lose their strength over time. Check the concentration of your wash solutions daily and adjust or replace them as needed.

Tips For Recovery and Re-Use of Chemical Solutions

Environmental impact issues and chemical costs in the 1960s and 1970s drove the move to CIP systems that could re-use caustic and acid solutions. In situations with light to moderate soiling, wash solutions can be returned to their appropriate CIP tank and re-used for subsequent cycles. The number of re-uses varies by chemical concentration and amount of soiling, but re-using some solutions for dozens of washes is not uncommon.

TIP: For heavy soiling applications, re-using the wash solution isn’t practical, so it is typically sent to drain after a single use. Also, a single-use system should always be used if your cleaning protocols demand that absolutely no cross-contamination occur between batches.

In many systems, it is common for the final rinse water to be recovered and reused as the pre-rinse solution for the next cleaning cycle. The residual heat and chemicals it retains from the final rinse helps make the following pre-rinse more effective and economical. However, the solution from the sanitizing rinse cycle should never be re-circulated under any circumstances.

Warning: Sanitizers reduce bacterial growth but don’t completely kill all pathogens in the system. Since sanitizing is the last step in the cleaning process, re-circulating sanitizing solution could risk spreading leftover contamination. Sanitizers can also be sensitive to high temperatures and can lose their effectiveness rapidly once they are in solution.

How to Calculate Proper Cleaning Temperature

Calculating accurate solution temperature is critical to effectively cleaning your system while reducing energy costs. Some studies have shown that every one-degree reduction in CIP solution temperature reduces energy needs by 1%, Which can result in significant savings over the course of a year.

We know that higher solution temperatures can increase the effectiveness of chemicals and mechanical action; they can also reduce the amount of time needed to clean properly. But considering the cost of energy to heat the solution, it is important that the temperature of each individual cleaning stage be calculated and controlled as accurately as possible.

Each stage of the cleaning process has its own optimum temperature range to balance effective cleaning with energy conservation. To the right are some typical CIP temperature ranges.

CIP StageApprox. Temperature Range
Pre-Rinse104° - 140° F
Caustic Wash140° - 185° F
Intermediate RinsesAmbient - 140° F
Acid Wash130° - 150° F
Final RinseTypically Ambient
SanitizerTypically Ambient

Clean-in-place Buying Guide

This Buying Guide for Clean-in-Place Solutions is a comprehensive resource for anyone who designs, owns, or operates processing systems and wants information about all aspects of CIP Systems.

Clean-in-place Buying Guide

Read Guide

Next Steps

Understanding the common chemicals used in CIP Cycles helps you use the right chemical cleaning agents in the right concentrations; which make a significant difference in the efficiency of your CIP system.

Purchasing and installing a CIP system for your processing facility is also a considerable undertaking, requiring analysis, planning and above all, partners.

The best first steps are

  • Create a team of knowledgeable operators
  • Create a team of managers from multiple departments
  • Connect with a trusted company that has vast experience in designing and building process and CIP systems

That’s where we come in.

CSI has the ability to engineer, design, and fabricate a custom clean-in-place system to meet your exact hygienic processing needs. CIP equipment from CSI helps you diagram, control, monitor, and document the cleaning methods that are essential to sanitary processing.

With CSI's state-of-the-art, climate-controlled fabrication shop, the quality of equipment leaving our facility is second to none. We offer in-house, Level II inspection in accordance with the latest ASNT recommended Practice No. SNT-TC-1A, so you can be certain your equipment meets industry standards.

To speak with a CIP expert, request a quote below or call 800.654.5635.


Central States Industrial Equipment (CSI) is a leader in distribution of hygienic pipe, valves, fittings, pumps, heat exchangers, and MRO supplies for hygienic industrial processors, with four distribution facilities across the U.S. CSI also provides detail design and execution for hygienic process systems in the food, dairy, beverage, pharmaceutical, biotechnology, and personal care industries. Specializing in process piping, system start-ups, and cleaning systems, CSI leverages technology, intellectual property, and industry expertise to deliver solutions to processing problems. More information can be found at www.csidesigns.com.