Key takeaways
-
Cleaning a stainless-steel brewery tank involves two distinct steps: an alkaline phase using caustic soda to remove organic residues (yeast, proteins, sugars, greasy films), followed by an acid phase when mineral deposits or beerstone are present.
- The 30% sodium hydroxide solution must be diluted to achieve the working concentration specified by the CIP protocol.
- For descaling, 75% phosphoric acid or citric acid can be used depending on the nature of the deposits, the equipment and the brewery’s protocol.
To clean a stainless steel tank effectively in a brewery, the protocol generally follows a logical sequence:
Why alternate between alkaline cleaning and acid descaling?
A brewing, fermentation, or conditioning tank can accumulate two broad types of deposits.
- The organic residues include proteins, yeast, sugars, and fats generated during brewing and fermentation. They generally require an alkaline cleaning step.
- By contrast, mineral deposits can form gradually on stainless steel surfaces. One example is beerstone, a stubborn deposit containing both mineral and organic compounds.
Cleaning with caustic soda alone may therefore be insufficient when mineral deposits have built up.
This alternating sequence treats different types of contamination in turn without directly mixing incompatible products.
| Step | Objective | Product / product category | Key precautions |
|---|---|---|---|
| 1. Pre-rinse | Remove loose residues | Water | Remove residues before chemical cleaning |
| 2. Alkaline cleaning | Remove organic soils | 30% sodium hydroxide solution used according to the established protocol | Adjust the parameters to the protocol |
| 3. Intermediate rinse | Remove alkaline residues before the acid step | Water | Never bring caustic soda and acid into direct contact |
| 4. Acid descaling | Remove mineral deposits and beerstone | 75% phosphoric acid or citric acid, depending on the protocol | Check the compatibility of seals and equipment |
| 5. Final rinse | Remove product residues before returning the tank to service | Water | Rinse thoroughly according to the facility’s protocol |
CIP protocol for a stainless steel tank in a brewery
1. Remove bulk residues
Before any chemical cleaning, completely remove the residues in the tank.
A pre-rinse removes loose material and reduces the amount of contaminants before the cleaning cycle.
2. Perform alkaline cleaning
A 30% sodium hydroxide solution can be used as a raw material to prepare an alkaline cleaning solution suited to the process.
A mistake we regularly see among professionals is trying to correct inadequate cleaning solely by increasing the product concentration.
Before increasing the dose, first check the type of deposit, the condition of the bath, and whether the solution is circulating properly throughout the system. A persistent mineral deposit may, for example, require an appropriate acid stage rather than a higher dose of caustic soda.
3. Rinse thoroughly
After alkaline cleaning, rinse thoroughly.
This step is essential before introducing any acidic product.
Never directly mix an alkaline solution containing caustic soda with an acidic solution.
Beerstone: when should you start an acid cycle?
Beerstone typically appears as whitish to grayish deposits, sometimes rough or firmly adhered, that persist after alkaline cleaning. It forms gradually as mineral compounds associated with organic residues from the brewing process accumulate.
An acid cycle should therefore be initiated based on the actual condition of the tank and the effectiveness of routine cleaning, rather than on a fixed schedule. It may be considered when deposits remain after the alkaline cycle, when surfaces become rougher, or when visual inspection reveals mineral buildup.
Phosphoric acid or citric acid: which should you choose?
The choice depends on the brewery’s cleaning process and site-specific requirements.
| Criterion | 75% phosphoric acid | Citric acid |
|---|---|---|
| Role in the protocol | Acid phase for treating mineral deposits after alkaline cleaning and an intermediate rinse. | An alternative for the acid cleaning or descaling phase after the alkaline cycle. |
| Form of use | A concentrated acidic raw material used to prepare a working solution suited to the brewery's protocol. | A raw material used to prepare an acidic cleaning or descaling solution. |
| When should it be considered? | When the brewery's protocol calls for acid treatment of persistent mineral deposits. | When citric acid is compatible with the process, equipment and chosen cleaning plan. |
| Selection criteria | Type of deposits, cleaning process, materials in the system and internal protocol. | Type of deposits, cleaning process, materials in the system and internal protocol. |
| Equipment compatibility | Check compatibility with seals, hoses, pumps, valves and other system components. | Check compatibility with seals, hoses, pumps, valves and other system components. |
| Precaution | Concentrated product: follow the handling instructions, safety data sheet and site's dilution protocol. | Do not automatically apply a protocol designed for another acid; adapt its use to the process. |
| Before returning to service | Perform a thorough final rinse in accordance with the system's cleaning plan. | Perform a thorough final rinse in accordance with the system's cleaning plan. |
The frequency of descaling depends in particular on:
- water hardness;
- the production process;
- how frequently the tank is used;
- cycle temperature;
- the effectiveness of routine cleaning.
When descaling is necessary, phosphoric acid or citric acid can be used according to the selected protocol. The concentration used, temperature, and contact time must be determined from the technical data sheets and validated based on the equipment, seals, and level of scale buildup in the system.
After treatment, check that visible deposits have disappeared and that the final rinse is satisfactory before returning the tank to service. If a deposit remains despite a properly performed acid cycle, reassess the diagnosis, the bath parameters, or the condition of the equipment's surfaces.
What role does sodium percarbonate play?
Sodium percarbonate is an oxidizing agent that can be incorporated into some cleaning protocols alongside the standard steps. Its role must, however, be distinguished from that of sodium hydroxide solution and the acids used for descaling.
It should therefore not be treated as a routine replacement. Using sodium percarbonate does not mean the sodium hydroxide alkaline phase is unnecessary, nor that acid descaling can be omitted when mineral deposits are present.
Finally, sodium percarbonate must not be added arbitrarily to a bath containing another cleaning product. Its use must be part of a defined step in the protocol, under the conditions specified in the technical data sheet and in accordance with the associated safety rules.
Sodium hydroxide and acids: check the seals before modifying a CIP process
The systems also include seals, hoses, pumps, valves, membranes, and plastic or elastomer components.
However, their resistance can vary considerably depending on the product and conditions of use.
Before changing a cleaning protocol, it is essential to check the equipment manufacturer’s recommendations and the chemical compatibility of the seals.
Mistakes to avoid when CIP-cleaning a stainless steel tank
| Mistake | Why avoid it |
|---|---|
| Using too much product | A higher dose does not necessarily improve cleaning and may place greater stress on equipment. |
| Mixing caustic soda and acid | The alkaline and acid steps must remain separate. A thorough intermediate rinse is essential. |
| Reusing a cleaning bath without checking its condition | A cleaning bath that is overloaded or degraded may become less effective and compromise cleaning quality. |
| Confusing the 30% sodium hydroxide solution with the concentration of the cleaning solution | The concentration of the commercial product is not the concentration of the cleaning solution after dilution. |
| Relying solely on sodium hydroxide for mineral deposits | Certain mineral deposits, such as beerstone, may require an appropriate acid descaling step. |
| Applying a CIP protocol to manual cleaning | Application conditions and mechanical action differ, so the parameters should not be carried over automatically. |
Cleaning performance depends more on a well-controlled protocol than on using an excessively concentrated product.
What should be done with the sodium hydroxide and acid baths after CIP?
Spent cleaning solutions must not be discharged without accounting for site-specific requirements.
Alkaline and acid cleaning solutions can significantly change the pH of wastewater.
The brewery must therefore incorporate their management into its operations:
- identification of wastewater generated by cleaning;
- separation of the different cleaning solutions, if necessary;
- pH monitoring when necessary;
- compliance with the rules governing the sewer system or on-site treatment;
- consideration of other substances present in the cleaning solution.
Discharge rules may vary by site, sewer system, and local requirements.
Can the same protocol be used in a winery?
However, the soils encountered are not exactly the same as in a brewery.
The protocol must therefore be adapted:
- to residues from winemaking;
- to the type of tank;
- to winery seals and equipment;
- to the operation’s hygiene plan.
Concentration, temperature, and contact time must not be transferred automatically from a brewing process to a winemaking process.
Which products should you use to clean stainless steel tanks professionally?
For craft breweries and wineries, Arcane Direct offers, among other products:
| Process requirements | Arcane Direct product | Function |
|---|---|---|
| Alkaline cleaning | 30% sodium hydroxide solution | Preparing the alkaline cleaning solution |
| Mineral scale removal | 75% phosphoric acid | Preparing the acidic cleaning solution |
| Alternative descaling option | Citric acid | Acid treatment according to protocol |
| Specific oxidizing action | Sodium percarbonate | Include only in suitable protocols |
Need help defining your cleaning protocol?
The choice of product and bath volume depends on your equipment and process.
The Arcane Direct team can help you choose the raw materials and packaging sizes suited to your brewery or winery.
Phone: 04 42 82 16 82
Email: contact@arcane-direct.com
REQUEST A TECHNICAL CALLBACK
