The Role of Sealing Materials in the Coffee Machine Industry

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August 2024

Key Facts at One Glance:

High quality sealing materials ensure safe, efficient, and consistent operation of coffee machines
The custom seals of Angst+Pfister meet stringent regulatory standards for the coffee machine industry
The seals resist mechanical wear, temperature changes, and chemical exposure

The Secret to Perfectly Brewed Coffee: A Deep Dive into Sealing Materials

What is the function of seals in coffee machines? The choice of the optimum material guarantees unlimited coffee enjoyment and takes into account the trends in coffee culture. High-purity silicone, EPDM or other innovative compounds provide distinct benefits when correctly applied. Angst+Pfister persistently researches the next generation of high-performance elastomers.

The coffee machine industry combines passion with perfection. Delicious coffee not only depends on quality machines and beans. The purity and durability of seals are also essential. Seals, the secret weapon of the coffee-making process, warrant a safe and unadulterated experience of the kind coffee aficionados are looking for.

Which challenges in developing high-quality seals for coffee machines need to be overcome? Which materials meet the requirements and ensure that the machines will function perfectly for many years?

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Coffee-Brewing Problems

1. Certified Purity

Task: Seals get into contact with water and coffee. Material purity is therefore essential. Many countries and markets are demanding increasingly stricter certifications. They stipulate: Which substances may be used in rubber compounds? What must not leak out under any circumstances?

Effect: Coffee machine seals must comply with strict market-specific purity standards to ensure unaffected quality and safety of the coffee. Market advantages are gained by using materials that meet the criteria of all relevant global markets.

2. Longevity

Task: Coffee machines are expected to withstand thousands of brewing processes during their operating life. Seals are exposed to constant mechanical stress, different temperatures, aggressive media or steam.

Effect: Seals should withstand abrasion and degradation and the loss of their material properties. Using high-performance materials with exceptional durability that are in no way impaired by complying with a wide range of requirements provides an advantage - otherwise there is a risk of cost-intensive maintenance.

3. Chemical Resistance

Task: Many substances in coffee machines, from greasy milk to acidic coffee and alkaline detergents, are aggressive to seals and chemically attack them.

Effect: Sealing materials have to withstand different chemical processes to ensure that the seals will retain their function for a long time. Manufacturers who want to stand out in their markets by providing quality - without leaks and contamination - are dependent on high-performance materials.

4. Temperature Changes

Task: Heating and cooling require sealing materials to be used in coffee machines that will retain their properties within a wide temperature range.

Effect: The materials must remain flexible and functional - even with constant brewing and cooling. This requires seal suppliers with profound expertise in materials to ensure the best coffee experience.

5. Expected Regulations (PFAS)

Task: The replacement of non-biodegradable PFAS is being discussed in many markets - regulatory constraints, some of which being unpredictable, are still in preparation. In sealing technology, fluorine-containing materials such as FKM are affected. Their combined resistance to heat and chemicals will leave a gap.

Effect: Many coffee machine manufacturers already want to exclude the usage of PFAS. This can negatively affect operating life and durability of coffee machines. Angst+Pfister has been researching alternative materials and will be launching them shortly.

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Engineering Solutions for Coffee Machines: Materials up to the Challenge

The choice of material depends primarily on where the seals are placed inside the coffee machine: What temperatures are prevailing there? The sealing specialists also consider the material's contact surfaces and the mechanical loads to which it is exposed. Finally, a number of approvals determine which compounds are suitable. These include, for example

1. Silicones (VMQ)

Advantages: Silicone is known for its purity and compliance with food safety standards. It can be used in a wide temperature range and does not react with coffee or cleaning agents. Owing to its flexibility and elasticity, silicone is ideal for permanent sealing applications in coffee machines.

When to use: Silicone seals are used in water ducts, filter baskets and wherever direct contact with food occurs. However, there are better materials available for contact with hot water or steam as well as for mechanical loads - for example in dynamic applications.

Examples: Angst+Pfister's high-purity silicone compounds also provide outstanding mechanical properties, and they are available in two degrees of hardness: PERTEC® UP VMQ 70.501-0, PERTEC® UP VMQ 50.501-02.

2. Ethylene Propylene Diene Monomers (EPDM)

Advantages: The advantage of EPDM is its exceptional resistance to hot water and steam. Its temperature stability and durability are outstanding, and it fulfills many food standards

When to use: Typically, it is used as O-rings and seals in the brewing chamber and in water-heating systems. EPDM is preferable at water temperatures of 100 degrees centigrade and above. However, it does not like fats (milk, coffee).

Examples: Angst+Pfister provides innovative materials available in two degrees of hardness that meet all globally relevant food approvals: PERTEC® UP EPDM 70.503-04, PERTEC® UP EPDM 80.503-01.

3. Fluorocarbon Elastomers (FKM)

Advantages: FKM provides excellent chemical resistance. Suitable for environments exposed to aggressive cleaning and decalcifying agents. The mechanical properties at high temperatures contribute to its durability.

When to use: Ideal for dynamic seals used in equipment parts that are frequently exposed to chemicals and high temperatures, such as pump seals and steam nozzles.

Angst+Pfister is now developing a high-purity HNBR to replace FKM in anticipation of expected regulatory constraints. FKM may no longer be permitted to use in a few years' time.

Innovative Sealing Partner Providing Expertise in Materials

By skillfully using these special materials, coffee machine manufacturers can master the dual task of providing both high material purity and long service life. Each seal material has a range of properties that are particularly suitable for different requirements within the coffee-preparation process - from resistance to high temperatures or aggressive chemicals to the certainty that every cup of coffee will be free from contamination.

The complex interplay of technology and material science supports the journey from bean to cup of coffee. The design of sealing solutions is developing in step with the advancing coffee culture. The following applies to seals: With constant innovation and careful material selection, the coffee machine industry is meeting the modern demands of coffee aficionados around the world. The right seals ensure that their beloved machines will brew perfect coffee, cup after cup, year after year.

Angst+Pfister is a reliable partner for coffee machine manufacturers. Thanks to our know-how in materials science, we are committed to excellence. Customized solutions ensure the perfect coffee experience.

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