Q&A｜Common Questions for Beginners with Home Espresso Machines
Many beginners using semi-automatic espresso machines encounter various issues such as:
- How to choose the right setup?
- What's the difference between different types of machines?
- Should I pick a vibration pump or a rotary pump for my home machine?
- How do I adjust extraction parameters?
- How to clean the brew head? ...
We have gathered answers to six of the most common questions to help you understand.
Q1: How to choose a heating system?
The structure of a coffee machine is complex, but the boiler and the pump are the two most important components: one provides stable temperature, and the other provides stable pressure. The most common heating systems on the market are:
Instant heating block:
○ Heats up quickly.
○ Ready for extraction soon after turning on.
Water storage boiler
○ More stable, better steam frothing ability.
○ Supports continuous brewing.
○ Comes in single-boiler, dual-boiler, or heat-exchanger models.
Tips: Instant heating blocks are suitable for those who want a quick cup in the morning, like office workers. If you care about flavor and want stable, continuous brewing, go for a water storage boiler, dual boilers are recommended for the best results.
Q2: Should I choose a vibration pump or a rotary pump for a home machine?
The type of pump affects extraction stability, and the pressure affects the amount of crema in the coffee. Generally:
Vibration pump:○ Smaller and cheaper.
○ Ideal for beginners using home machines.
Rotary pump:
○ Quieter, more stable pressure, and more durable.
○ If budget allows, consider a rotary pump.
Q3: What are the differences between various brew heads?
The brew head connects the machine, boiler, and portafilter, controlling the flavor extraction. Taking Gemilai as an example, the main types of brew heads currently available are:
The brew head and extraction boiler are integrated in an up-down structure with zero distance between the water path and the boiler, reducing temperature loss during extraction. The water circulation heat exchange design ensures stable and precise temperature control.
Features four major characteristics: heat exchange, siphon insulation, mechanical pre-infusion, and high thermal conductivity from pure copper. The clever heat siphon effect uses the boiler’s heat to warm the brew head, ensuring long-lasting heat retention and more stable extraction.
Connected horizontally to a 300ml PID temperature-controlled water storage boiler. The boiler is integrated with the brew head, ensuring zero distance between them, for precise temperature control. The extraction temperature is visible and adjustable.
Equipped with a PTC heating element, this design effectively reduces temperature loss from the water as it travels through the pipes to the brew head, minimizing extraction temperature differences and ensuring stable coffee extraction.
Gemilai has long been committed to bringing commercial standards and technology into home machines. This system features a 58mm commercial portafilter size and a metal brew head with a high-density single-layer dispersion screen, making it a signature feature of Gemilai’s product design.
Q4: Why choose the 58mm size?
With the same amount of coffee grounds and extraction time, the coffee puck in a 58mm portafilter is relatively thinner, meaning the surface area of the coffee that comes in contact with water is larger, allowing for better water penetration and more efficient extraction. The 58mm portafilter is a commercial configuration and, when paired with the 58mm commercial extraction system, results in more thorough extraction, providing a professional, café-level coffee experience.
Q5: How to adjust extraction parameters?
Extraction status can be easily observed by the flow rate. Generally, over-extraction leads to a slower flow rate, while under-extraction results in a faster flow rate. However, the ultimate judgment comes from the flavor. The typical extraction parameters are:
Coffee dose- Single espresso coffee grounds: 9-12g
- Double Espresso coffee grounds: 17-20g
- Water Temperature: 194-205°F
- Grouphead Pressure: 9-12 bar
- Extraction Time：25±5s
- Powder-to-liquid Ratio: 1:2~2.5
These are standard extraction references. Specific adjustments should be made based on the machine, coffee type, and personal taste preferences to find the right parameters for you.
Q6: How to clean the brew head?
Regular cleaning and maintenance of the brew head can extend the machine’s lifespan and ensure the coffee's flavor quality. Prepare the following tools: a clean brush, a clean cloth, and a cleaning mat.
Gemilai's product line for home and commercial use
Bringing commercial standards and technology into the home,
Gemilai continuously upgrades the design to enhance the user experience.
