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Espresso Machine Water Systems: Plumbing-in vs. Reservoir Models

Espresso Machine Water Systems: Plumbing-in vs. Reservoir Models

The choice between plumbing-in or using a reservoir water system in an espresso machine is more than a matter of convenience—it's a decision that impacts everything from the flavor of the coffee to the functionality of the machine. In this blog, I’ll delve into the nuances of both systems, exploring how they operate, their benefits and limitations, and the influence they have on the espresso brewing process. Whether you're setting up a cozy home coffee corner or running a bustling cafe, understanding the differences between these water systems is essential for optimizing your espresso experience and ensuring your machine's efficiency and longevity.

Understanding Water Systems in Espresso Machines

Water systems in espresso machines are pivotal, as they directly affect both the espresso extraction process and the overall health of the machine. Here’s how these systems function and the importance of water quality:

  • Functioning of Water Systems:
        • In espresso machines, the water system is responsible for supplying water to the boiler, where it is heated to the optimal temperature for espresso extraction. In reservoir models, water is stored in a built-in tank that needs to be manually filled, while plumbing-in models connect directly to a water line, offering a continuous supply.
        • The pump in the machine then pressurizes the hot water and forces it through the coffee grounds in the portafilter, extracting the coffee's flavors, oils, and essences to create espresso.
  • Role of Water Quality:
      • Water quality is crucial in espresso making, as it can significantly influence the taste of the coffee and the longevity of the machine. Impurities or excessive minerals in water can lead to scale buildup, affecting the machine's internal parts and leading to potential malfunctions.
      • For the espresso itself, the mineral content of the water can alter the extraction process, impacting the flavor profile of the coffee. Ideally, water used in espresso machines should be clean and balanced in mineral content to ensure the best tasting espresso and to prevent scale accumulation that can damage the machine.

    Reservoir (Tank) Models

    Reservoir (Tank) Models espresso machine

    Reservoir-based espresso machines, also known as tank models, have an inbuilt water tank that needs to be manually filled with water. Here's a look at how they operate and their pros and cons:

  • Operation:
        • These machines draw water from the built-in reservoir to heat and use for espresso extraction. The reservoir is typically accessible from the top or side of the machine, allowing for easy filling and monitoring of water levels.
        • The water is then heated in the machine’s boiler before being pushed through the coffee grounds at high pressure to brew espresso.
  • Advantages:
        • Portability: One of the significant advantages of reservoir models is their portability. Since they are not tied to a water line, they can be placed anywhere and moved easily, which is ideal for home use or in settings where a direct water connection is not feasible.
        • Ease of Setup: These machines generally require less setup compared to plumbing-in models, as there’s no need for a water line connection. Setting up involves simply filling the reservoir and powering on the machine.
  • Limitations:
      • Regular Refilling: The water tank needs to be refilled manually, which can be a drawback in high-usage environments, as it requires frequent monitoring to ensure the machine doesn’t run out of water.
      • Potential for Stagnant Water: If the machine is not used regularly, water in the reservoir can become stagnant, which might affect the taste of the coffee and the cleanliness of the machine. Regular changing of the water is recommended to maintain freshness.

    Plumbing-in (Direct Connect) Models

    Plumbing-in espresso machine

    Plumbed-in espresso machines, also known as direct connect models, are designed to be hooked up to a water line, providing a continuous and automatic water supply. Here's an overview of their mechanism and the advantages and drawbacks:

  • Mechanism:
        • In these models, the machine is connected directly to a water source, eliminating the need for a reservoir. This setup allows for an uninterrupted water supply, with the machine drawing water as needed for heating and brewing.
        • The plumbing system typically includes a water softener or filter to ensure the water quality is optimal for coffee brewing and to protect the machine from scale buildup.
  • Benefits:
        • Constant Water Supply: The most significant advantage is the continuous water supply, which is particularly beneficial in high-volume settings like cafes and restaurants, as it reduces downtime for refilling.
        • Automatic Refilling: With a direct water connection, the machine automatically refills itself, ensuring a consistent water level for brewing at all times, which enhances operational efficiency. Many commercial espresso machines have this facility.
  • Drawbacks:
      • Installation Complexity: Setting up a plumbing-in model can be more complex than a reservoir machine, requiring a compatible water source and possibly professional installation to ensure the plumbing is correctly configured.
      • Potential Plumbing Issues: The reliance on a water line can lead to potential challenges, such as water pressure fluctuations or leaks, which may require additional maintenance or repairs.

    Comparing Plumbing-in vs. Reservoir Models

    When evaluating plumbing-in and reservoir espresso machine models, the comparison across convenience, water quality, maintenance, and suitability for various settings is crucial:

  • Convenience:
        • Plumbing-in Models: Offer high convenience in busy environments due to their automatic water refilling capability, eliminating the need for manual intervention to maintain water levels.
        • Reservoir Models: Provide the convenience of mobility and simpler installation, as they can be placed anywhere without the need for a water line.
  • Water Quality:
        • Plumbing-in Models: Can be directly connected to a water filtration system, ensuring consistent water quality and taste. However, they require a stable and clean water source to prevent machine issues.
        • Reservoir Models: Allow for the use of bottled or filtered water, giving more control over water quality, but they rely on regular manual refills and monitoring to maintain freshness.
  • Maintenance:
        • Plumbing-in Models: May require more complex installation and maintenance, including potential plumbing and water pressure adjustments, but they benefit from consistent water supply and integrated filtration systems.
        • Reservoir Models: Generally easier to maintain from a water system perspective, needing regular cleaning and refilling. However, stagnant water can be a concern if not refreshed regularly. Have a look at our blog on the maintenance and troubleshooting tips for espresso machine.
  • Suitability for Different Settings:
      • Plumbing-in Models: Best suited for high-volume environments like cafes and restaurants where the demand for coffee is continuous and high.
      • Reservoir Models: Ideal for home users, small offices, or locations where plumbing access is limited or non-existent, offering flexibility in machine placement and easier setup.

    Choosing the Right Model for Your Needs

    Selecting the appropriate water system for an espresso machine involves considering various factors, such as the location, expected usage volume, and available maintenance capabilities. Here's how to determine the best fit for different settings:

  • Location Considerations:
        • Assess the availability of a water connection and the quality of the water in your location. Plumbing-in models require a direct water line and may benefit from areas with high-quality tap water, while reservoir models are more flexible regarding placement and can use filtered or bottled water.
  • Usage Volume:
        • High-volume environments like coffee shops or busy offices should consider plumbing-in models for their efficiency and ability to handle continuous use without the need for frequent refills.
        • For home users or small offices with lower coffee consumption, reservoir models are often sufficient and more convenient due to their portability and ease of use.
  • Maintenance Capabilities:
      • If regular and professional maintenance is feasible, a plumbing-in model can be a good choice, as it may require more complex installation and upkeep.
      • Reservoir models, while easier to install and maintain on a daily basis, still need regular cleaning and water changes to ensure optimal machine performance and coffee quality.


    • Home Users: Typically, reservoir models are more suitable due to their ease of use, minimal installation requirements, and the flexibility to use preferred water types.
    • Offices: Depending on the size and coffee demand, smaller offices might opt for reservoir models, while larger offices with high usage might benefit more from plumbing-in models for their convenience and efficiency.
    • Coffee Shops: Plumbing-in models are generally recommended for coffee shops due to the consistent demand for coffee, needing a reliable machine that can handle high volume and quick refills. If you are a coffee shop owner then I’d suggest you to have a look at our Rancilio Commercial Espresso Machines.

    Choosing the right espresso machine water system hinges on balancing these considerations to match the specific needs and constraints of your environment. This ensures not only the best coffee experience but also the most practical and sustainable use of the machine over time.

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