Diagnosis
This issue is caused by a lack of "puck resistance." In an espresso machine like the Bambino Plus, the pump pushes water through the coffee grounds at a specific pressure. If the water flows through the basket too quickly (known as "channeling" or "under-extraction"), it means the water has found the path of least resistance. Instead of saturating the coffee and extracting the oils and flavors, the water rushes through gaps in the coffee bed, resulting in a thin, watery liquid with a pale crema. This typically happens due to one of three variables: the grind size is too coarse, the dose of coffee is too low for the specific basket size, or the tamping pressure is inconsistent. If you are using the single-wall (non-pressurized) baskets, the machine relies entirely on your technique to create the resistance. If you are using the double-wall (pressurized) baskets and still seeing this, you likely have a clog or a leak in the basket seal, but 90% of the time, it is a grind and dose mismatch.
How to Fix It
To achieve a syrupy, rich extraction, follow these precise calibration steps:
- Verify Your Dose: Use a digital scale. For the double-shot single-wall basket, weigh out exactly 18 grams of fresh espresso beans. If you are using the single-shot basket, use 9-11 grams. Do not guess by "filling to the top," as bean density varies.
- Adjust the Grind: Move your grinder setting to a finer notch. The coffee should feel like fine table salt or powdered sugar. If the water still gushes out in less than 20 seconds, go two notches finer.
- Distribute and Tamp: Level the grounds with your finger or a distribution tool to ensure there are no mounds. Place the portafilter on a flat surface and press the tamper straight down with firm, even pressure (approximately 30 lbs of force) until the coffee resists further.
- The Razor Trim: Insert the Breville Razor™ tool into the portafilter. If the tool doesn't touch the coffee, you haven't added enough. If it removes a large chunk of coffee, you've overfilled. The tool should just barely skim the surface of the puck.
- Timing the Shot: Start the extraction. You are looking for a "mouse tail" stream. The goal is to get 36-40g of liquid espresso in approximately 25-30 seconds.
If That Didn't Work
- Switch to Pressurized Baskets: If you are using pre-ground coffee from a grocery store, it is often too coarse for the single-wall baskets. Swap to the double-wall (pressurized) filter basket. These have a tiny hole at the bottom that artificially creates the pressure needed to produce crema even with coarse grinds.
- Check for Channeling: Look at the bottom of the portafilter after the shot. If you see small holes or "craters" in the coffee puck, water is tunneling through. This is solved by using a WDT tool (a thin needle) to stir the grounds before tamping to remove clumps.
- Increase Temperature: If the coffee tastes watery/sour despite a slow flow, your beans might be too light. Ensure the machine is fully preheated by running a "blank" shot (water only) through the portafilter into your cup before pulling the actual espresso.
- Freshness Check: If your beans were roasted more than 4 weeks ago, they lose the CO2 gases required to create resistance and crema. Try a bag of beans roasted within the last 14 days.
Heads Up
- Avoid Over-Tamping: Pressing harder than 30 lbs won't make the shot slower; once the coffee is compressed, additional force does nothing but tire your arm. Focus on the grind size instead.
- Purge the Group Head: Always run the pump for 2 seconds before inserting the portafilter to clear any old grounds and stabilize the temperature of the brew head.
- Clean the Shower Screen: Use the provided cleaning tablet every 200 shots. A clogged shower screen can cause uneven water distribution, leading to "fast paths" and watery coffee.
- Water Quality: Use filtered water. Mineral buildup in the thermocoil can cause temperature fluctuations, which affects how the coffee extracts and tastes.