The short answer: If an espresso only drips, Sage, Gaggia and Lelit list grind size, coffee quantity and tamping as causes in their troubleshooting tables, alongside the tank, temperature, limescale and blocked baskets. The order differs by manufacturer: Gaggia UP and Lelit start with the coffee, Sage and Gaggia E24 with the tank and temperature. How often you backflush, descale or replace the gasket is set by each manufacturer itself: for the Classic E24, Gaggia requires descaling every 2 months, and Sage every 90 days at hardness level 4. An annual interval for the group gasket appears in no manual of a home machine that we checked; only La Marzocco counts the replacement as part of annual maintenance on its professional-grade home machines.
All the information below comes from manuals, authorities and studies, with the source given in the text. The order of the checking steps is our own logic, and where we make an assessment, it says so.
Which causes manufacturers name first
A portafilter machine has few stages: tank, pump, heater, brew group with shower screen, portafilter with basket. For one symptom, the manufacturers’ tables usually list several causes and do not weight them. So it is not true that every fault points to exactly one stage. The table reproduces what the manuals say and applies only to the models named.
| Symptom | Causes according to the manufacturer | Source |
|---|---|---|
| Espresso only drips or does not run at all | Sage: machine not up to temperature, tank empty or not seated, descaling needed, coffee too fine, too much coffee, tamped too hard, basket blocked. Gaggia UP: grind too fine, compressed too much, too much coffee, filter blocked. Lelit Victoria: grind too fine, too much coffee, pressed too hard, brew group blocked | Sage Barista Express p. 20; Gaggia Classic UP pp. 57 and 58; Lelit Victoria p. 25 |
| Coffee runs too fast | Gaggia UP: too little coffee, ground too coarse, pressed too lightly | Gaggia Classic UP pp. 57 and 58 |
| Coffee puck too wet | Gaggia UP: coffee too coarse, too little coffee in the filter holder | Gaggia Classic UP pp. 57 and 58 |
| Water escapes at the portafilter | Gaggia E24: portafilter not inserted properly, gasket dirty, residue on the rim. Sage: also tamped too lightly, too much coffee, silicone gasket of the shower. De’Longhi Dedica: boiler gasket has lost elasticity, holes or basket blocked | Gaggia Classic E24 p. 29; Sage p. 21; De’Longhi Dedica p. 13 |
| Portafilter does not lock in | De’Longhi Dedica: too much coffee in the basket | De’Longhi Dedica pp. 13 and 14 |
| No water, pump loud | Gaggia E24: water in the tank, pump not activated (fill the circuit), coffee quantity. Sage: a pulsating noise is normal, otherwise tank empty or not seated. De’Longhi: tank not inserted properly | Gaggia E24 pp. 22 and 29; Sage p. 22; De’Longhi Dedica p. 13 |
| Drip tray fills quickly | Sage: normal automatic flush after steam and hot water, otherwise tank not seated | Sage pp. 21 and 22 |
| No steam, milk does not froth | Gaggia E24: steam nozzle blocked, nozzle too deep, milk too hot. Sage: operating temperature not reached, tank, limescale, nozzle blocked. Lelit: hole at the end of the wand blocked | Gaggia E24 p. 29; Sage pp. 21 and 22; Lelit Victoria pp. 25 and 26 |
| Espresso too cool | Gaggia E24: machine still heating up, grind too coarse, cold cups, portafilter not preheated. Sage: also milk, limescale. Lelit: operating temperature not reached, portafilter not heated | Gaggia E24 p. 29; Sage pp. 21 and 22; Lelit Victoria p. 25 |
Our assessment on the order: start with the coffee in the basket, because it is the cheapest step and because Gaggia UP and Lelit start there (Sage and Gaggia E24 ask about the tank and temperature first), then the basket and shower screen, then the water path, and finally the gasket and valves. Change one thing per attempt, otherwise you will not know afterwards what worked.
Espresso drips or gushes through: grind size, quantity, basket
For an espresso that only drips, Gaggia UP and Lelit Victoria start with the coffee in the basket: too fine, too much, pressed too hard. Sage and Gaggia E24 name temperature and the tank respectively first, and list grind size, quantity and tamping afterwards. If it runs too fast, the causes reverse. Cameron and colleagues described the mechanics in 2020 in the journal Matter: a slower flow is achieved with less water pressure, a finer grind, a more densely packed bed or more coffee, also in combination. The shower screen and the holes in the basket come only after that.
Sage gives as guide values an output time of 25 to 30 seconds, 8 to 11 g of coffee for one cup and 16 to 19 g for two. Over 35 seconds counts as too fine at Sage (bitter, astringent), under 20 seconds as too coarse (underdeveloped, sour). That is one manufacturer’s rule of thumb. Gaggia and Lelit link grind size, quantity and tamping only to the speed, not to the taste. For filter coffee, Batali, Ristenpart and Guinard found in 2020, in 270 brews, that bitterness rose with brew strength and not with yield; the equation “sour is under-extracted, bitter is over-extracted” is therefore a simplification, and the study measured nothing for espresso. The taste side is covered in the guide Espresso Basics.
Our order, if the grind size seems plausible:
- Weigh the dose and the drink again. If you only estimate, you look for the fault in the machine although the quantity is what deviates.
- Wipe the basket rim and tamp level. Gaggia and Sage name residue on the rim as a reason for water at the portafilter, De’Longhi a dirty portafilter.
- Let water run from the brew group without the portafilter. If water comes out strongly, the constriction lies, by our deduction, in the portafilter or in the coffee bed; if little comes out, in the water path or in the shower screen.
- Clean the basket and portafilter according to the manual. In case of a fault in the output, Gaggia puts the filters in boiling water for 10 minutes. If holes stay blocked, Sage dissolves a cleaning tablet in hot water and soaks the basket and portafilter for about 20 minutes. For its powder, Urnex gives 6 g per litre of hot water and 30 minutes, without immersing the handle.
- Only then turn to the water path.
You often read that needles and wire do not belong near a basket and that widened holes ruin it. As a general rule, that is not correct. Sage prescribes cleaning blocked holes with the needle on the supplied cleaning tool, De’Longhi names a needle for the Dedica where needed, and Lelit clears the steam hole of the Victoria with a needle. We found no evidence that holes are permanently damaged in the process. We would work according to the manual for your machine; if it mentions no needle, leave it out.
Uneven shots despite a clean machine
If the espresso varies from day to day although the basket, shower screen and water path are fine, the cause often lies in the coffee bed itself. Cameron and colleagues call espresso the most variation-prone of the common coffee formats and list grind size, coffee quantity, water pressure, temperature, beverage quantity, tamping force and flow as the adjustable variables. In 2023, Lee, Smith and Arshad showed, in a simplified model with two flow paths, how a small difference in porosity and permeability grows through flow and extraction until one path is leached out. That is not a measurement on a real puck. Channelling, clumps and distribution are covered in the guide Espresso Basics; here the subject is the machine.
Water path, pump and pressure
If nothing flows from the brew group, the first question is the tank. Gaggia E24 and De’Longhi put it at the start of their tables; at Sage it comes after the temperature. Sage and De’Longhi explicitly require that it is inserted correctly: De’Longhi writes that you should press it down lightly so that the valves in the base open. For the Classic E24, Gaggia describes the case in which the pump temporarily does not start by itself because of an air bubble on first use or after a long standstill. The manufacturer then has you let about one cup of water run from the wand with the steam knob open, close the knob and press the coffee button again. That is the description for this one machine. Gaggia also warns against pressing the coffee button without first filling the circuit. According to our German review, Rancilio requires for the Silvia that you switch on only with a filled tank, because otherwise the heating element is damaged.
According to Sage, a pulsating pump noise is normal operation on the 15-bar pump of the Barista Express. You often read that a pump rattles hard and irregularly when there is air and that a tank valve sticks after a long standing time. We found no evidence for that in any manual.
Gaggia’s safety booklet (print date 31 August 2020, applies to the brand’s manual machines) names three water rules: never fill the tank with warm, hot or mineral water, use fresh water for every use, and do not store the machine below 0 °C, because residual water in the heating system can freeze.
On pressure: the 15 or 20 bar on boxes is not pressure at the coffee bed. In its catalogue, CEME lists an average of 20 bar for the E4 vibration pumps and 15 bar for the E5; the characteristic curve plots pressure against flow, and the maximum value applies with the outlet closed. For the coffee bed, the historical SCAA definition gives 9 to 10 atmospheres (1 atm is 1.01325 bar). A 2017 survey by the Barista Guild of America among 275 baristas gave an average extraction pressure of 8.5 bar, with 9 bar the most common answer. In 2002, Andueza and colleagues compared Arabica espressos at 7, 9 and 11 atm: at 9 atm they showed good foam consistency and many key aroma compounds, and 7 and 9 atm differed from 11 atm. More pressure was not better there. Baristas were surveyed, not home users, and the study says nothing about household machines with an overpressure valve. For the Victoria, Lelit gives 8 to 10 bar at extraction.
Whether your pressure gauge has to read in the upper, middle or lower range cannot be said without your machine’s scale. We could not substantiate the widespread claim that a needle position away from the upper range is the normal state.
Water at the portafilter and drips from the brew group
If water escapes at the portafilter during brewing, Gaggia checks three points on the Classic E24: is the portafilter seated correctly, is the gasket dirty, is there residue stuck to the rim? A worn gasket is not mentioned in that table. Sage adds tamping too lightly, too much coffee and the silicone gasket on the shower, which has to be replaced “over time”. For the Dedica, De’Longhi writes that the boiler gasket may have lost elasticity or be dirty and must then be replaced at a customer service centre. For its professional-grade home machines (post of 14 December 2023), La Marzocco describes the group gasket drying out and becoming brittle over time, being among the most frequently replaced parts, with its replacement counted as part of the machine’s annual preventive maintenance.
| Manufacturer | What it says about the gasket | Who replaces it |
|---|---|---|
| Gaggia (Classic E24, UP) | only “gasket dirty” as a checking point; repairs only by the authorised customer service (safety booklet) | Customer service |
| Sage (Barista Express) | silicone gasket of the shower “over time”, no interval | User, replacement with an Allen key described |
| De’Longhi (Dedica) | boiler gasket has lost elasticity or is dirty | Customer service centre |
| La Marzocco (professional-grade home machines) | wear, drying out, part of annual preventive maintenance, no figure in months or shots | Maintenance |
| Lelit (Victoria) | group gasket is brushed when backflushing, a replacement is not described | open |
Two widespread claims are only partly supported by the sources. Of the manufacturers checked, only La Marzocco names an annual interval, for its professional-grade home machines and as part of maintenance; for the home machines there is none in the manuals, and “about once a year” otherwise comes at most from retailers. And replacement is not everywhere among the jobs you can do without a workshop: only Sage describes it for the user. For reassembly, Sage writes to turn the screw two to three times by finger and then tighten it with the Allen key until it sits without a gap in the inner spray head. That is not “hand-tight only”. Replacement gaskets are obtained from Sage through customer service.
Drips after brewing need a distinction. For the Classic E24, Gaggia writes that after removing the portafilter some water still drips from the brew group, and puts this down to the pressure in the system. The word three-way valve does not appear there. La Marzocco explains the principle: after brewing, the three-way valve diverts water into the drip tray and relieves the brew group, so that the portafilter can be removed safely. On machines without a valve, the group stays under pressure. A valve clogged with coffee residue impairs the flow, and regular backflushing keeps it clean.
That implies less than is often claimed. No document shows that permanent dripping is due to coffee grounds in the valve seat or a solenoid valve that does not close. Nor does any show that wet pucks on “simple thermoblock machines” are due to a missing valve. Gaggia puts a wet puck on the Classic UP, which according to our German review has a solenoid valve, down to a grind that is too coarse and too little coffee. For the Dedica EC685 and the Classic EM450, our German review records that De’Longhi names a three-way valve neither as present nor as absent. For the Gaggia Classic Evo Pro, Gaggia states a three-way solenoid valve for constant pressure and dry pucks, a manufacturer’s claim without a measured value.
Backflushing and descaling: what each manufacturer prescribes
The data scatter most here. A uniform “backflush weekly” is not documented.
| Machine | Backflushing | Descaling | Source |
|---|---|---|---|
| Gaggia Classic UP | monthly with a blind basket and a quartered Gaggia tablet, pump 5 seconds, wait about 30 seconds, at least 10 repetitions | no descaling programme; for limescale, water that is not too hard, a softener if necessary, otherwise the service centre | Manual Rev. 03 (2026) pp. 54, 55 and 57 |
| Gaggia Classic E24 | not recorded by us | every 2 months of use, only Gaggia descaler, 20 minutes contact time | Manual pp. 27 and 28 |
| Sage Barista Express | cleaning cycle with disc and tablet (about 5 minutes) when CLEAN ME lights up | 90 days at hardness level 4, 60 days at level 6 (Sage’s own strips, not German degrees of hardness); water filter after 90 days or 40 litres | Manual pp. 16 and 17 |
| Sage UK blog | weekly (listed under “Monthly cleaning routine”), only with a three-way valve | Sage blog | |
| De’Longhi Dedica | does not appear in the manual; every 200 coffees run about 0.5 litres of water through without powder | when the orange light flashes, only De’Longhi descaler | Manual pp. 10 to 12 |
| Lelit Victoria | monthly, blind basket, 3.5 g Lelit cleaner | only natural descaling products, resin filter as prevention | Manual pp. 22 to 24 |
| Lelit Anna | at least weekly or every 100 coffees (according to the review, following the manual, Rev. 08/2023) | according to the review, resin filter recommended | Review of the Anna |
| Lelit Elizabeth | weekly | annually by a qualified technician | Review of the Elizabeth |
| Rancilio Silvia | daily (edition 10/2019) or weekly (08/2016) | no descaling chapter in either edition | Review of the Silvia |
| Urnex (commercial machines) | every evening | Urnex FAQ |
Our assessment: what counts is the manual for your machine, not an average. If backflushing is not mentioned there, as with the Dedica, it is not mandatory. Sage UK ties it to a three-way valve; a blind basket alone is not sufficient as a condition. On the product to use, the manufacturers are clear: Gaggia prohibits vinegar and other descalers, De’Longhi and Sage require their own product, and Lelit allows only natural ones. In 2003, Stiftung Warentest called vinegar taboo for coffee and espresso machines because it can attack metal and plastic parts; bio descalers based on citric acid were mostly permitted, and the instructions for use should be followed. Citric acid is not approved by the portafilter manufacturers checked here. Neither the foundation nor any of these manufacturers names gaskets as a reason against vinegar. An interval “by water hardness instead of calendar” is given in this table only by Sage. How hard your water is is covered in the guide Water Hardness and Coffee, and the procedure in the guide Descaling and Cleaning.
After descaling, the recommendation of the BfR (German Federal Institute for Risk Assessment; as of 7 May 2025) applies: rinse well, repeat the manufacturer’s rinsing steps, and insert a rinsing step with water only before preparation during daily start-up. On the cause, it says in the subjunctive that the lead may have been dissolved from metal components by acidic descaling products.
Steam wand and milk temperature
If water comes out of the wand first, there is condensate in it. On the Classic E24, Gaggia has you open the knob slightly after 15 to 20 seconds, when the steam light is on, to let the condensate out, and then close it for frothing. Lelit advises releasing about 2 seconds of steam before frothing. If no steam comes, Gaggia names a blocked nozzle and one immersed too deep, and Sage adds an operating temperature not reached and limescale. Lelit clears the hole at the end of the wand with a needle. Afterwards: Sage wipes the nozzle immediately with a damp cloth and releases a little steam; Gaggia advises wiping the wand after every frothing, releasing one to two seconds of steam, and washing it more thoroughly under running water.
At Gaggia there is one more limit: steam delivery on the Classic E24 should last 60 seconds at most, because longer can empty the boiler. For the next coffee, you lower the boiler temperature with hot water from the brew group, otherwise the coffee may taste burnt. On De’Longhi, the boiler has to cool down after steam for espresso, and both lights flash until it is ready.
How hot milk may get is answered differently by the sources:
| Source | Figure |
|---|---|
| Sage (Barista Express) | recommended 60 to 65 °C |
| De’Longhi (Dedica) | ideal value 60 °C |
| Lelit (Victoria) | milk cannot be frothed above 65 °C, do not exceed 65 °C |
| Stiftung Warentest (test 2/2018, barista Eric Wolf) | 65 to 70 °C, otherwise the foam becomes coarse-bubbled and collapses faster |
| Sage UK blog | 60 to 65 °C, proteins denature on overheating around 70 °C |
Our assessment: we would stay with the manufacturers’ values, that is, 60 to 65 °C. You often hear that microfoam breaks down above 65 °C. In the journal Foods, Zhang and colleagues showed only that whey proteins denature progressively more as the temperature rises; that concerns the taste and sensory qualities of the milk, not the stability of foam, and the study does not support a jump at 65 °C. The practice of frothing is covered in the guide How to Froth Milk.
Why the espresso arrives too cool
The table above shows that Gaggia, Sage and Lelit name several reasons at once, not just one. What they share is a machine that is not yet up to temperature and a portafilter or cups that are cold. Gaggia advises leaving the clean portafilter clamped in between shots so that the brew group stays evenly warm. For the Rancilio Silvia, our German review stresses that the light only reports the boiler and that the group and the brass portafilter need their own time; the recommendation to leave the portafilter clamped in is, there, the review’s professional reasoning and not a manufacturer’s requirement.
How long that takes depends on the model. For the thermoblocks of the Dedica Style and Arte, De’Longhi advertises extraction temperature in just 40 seconds. In the German Lelit shop, it says “less than 15 minutes” for the Elizabeth and “less than 10 minutes” for the Anna and the Victoria; the international product page of the Victoria says only “ready in a few minutes”. For the Classic E24, Gaggia has you wait a few minutes before the first espresso, and Rancilio gives no figure at all. A quarter of an hour as a rule for all machines with a heavy metal group cannot be derived from this; it is at most the upper limit for individual models, and the figures are manufacturers’ statements without measuring conditions.
The design also determines how you work. In its Tech Talk (1 February 2021), La Marzocco describes the systems from the viewpoint of a maker of professional machines:
| Design | What La Marzocco writes | Limitation |
|---|---|---|
| Single boiler | one boiler for espresso and steam; after steam, the temperature must drop before the next espresso, flushing speeds this up; no constant temperature stability | A manufacturer’s account of a competing principle |
| Heat exchanger | brew group and steam at the same time; if left unused for too long, the machine can overheat, a cooling flush before every shot is recommended | applies to the design in general |
| Dual boiler | two boilers; for its own system, a temperature stability under 0.6 degrees with stainless steel and PID | applies to La Marzocco professional machines, not an independent measurement |
| Thermoblock | De’Longhi gives 40 seconds to extraction temperature; the Advanced Thermoblock of the Dedica Maestro Plus offers higher stability with active control | pure manufacturer advertising without a measured value |
Warranty, repair and customer service
According to its safety booklet, Gaggia has repairs carried out exclusively by an authorised customer service. Anyone who ignores regular descaling loses the warranty claim for the repair; missing cleaning and maintenance that leads to a defect likewise excludes the warranty. Third-party accessories that Gaggia does not expressly recommend void the warranty. De’Longhi writes that unsuitable products or irregular descaling could cause defects that the manufacturer’s warranty does not cover.
That is the manufacturer’s warranty. The statutory warranty for defects (Gewährleistung) runs separately from it: under German law, claims for defects on purchase normally become time-barred two years after delivery (§ 438 BGB). If a condition that deviates from the contract shows within one year, it is presumed that the goods were already defective at the transfer of risk (§ 477 BGB). That opening the housing ends the statutory warranty is not in the text of the law. It is documented only for the manufacturers’ warranty conditions. Which interventions your retailer tolerates in a dispute is a legal question that we do not answer.
We give no rule of thumb for “repair or buy new”. We found no statistics on repair costs and failures of portafilter machines.
Machines and products we link here
The statements about the machines come from our revised German reviews and the manuals behind them; the intervals are in the table above. For the Gaggia Classic Evo Pro, the review calls gaskets wear parts by design. The Gaggia Classic UP has no descaling programme, and the warranty booklet excludes limescale as wear. The Sage Barista Express separates CLEAN ME cleaning from descaling and works in the 54 mm format. Care differs by model at Lelit: Victoria, Anna and Elizabeth; the Elizabeth is a dual boiler and weighs 15.3 kg according to Lelit. According to the review, you switch on the Rancilio Silvia only with a filled tank. The De’Longhi Dedica EC685 and the Classic EM450 have a thermoblock, and for both the manual leaves open whether a three-way valve is fitted.
For the cleaning products, the manual’s reservation always applies. Urnex Cafiza is described for backflushing with a blind basket (3 g, 10 seconds of brewing, 10 seconds of pause, five times) and for soaking; the blind basket must match the portafilter diameter, and Urnex’s recommended interval applies to commercial machines. durgol swiss espresso is a sulfamic acid descaler, also for portafilter machines according to the manufacturer; for a steam boiler or heat exchanger machine, the review advises looking at the machine manufacturer’s documents first. The De’Longhi EcoDecalk is a lactic acid descaler, and 500 ml is enough for five uses of 100 ml each; “faster and more effective than citric acid” is advertising without a measurement.
Which machine suits you is covered in the guide Espresso Machine Buying Guide. The accessories you need, from tamper to scale, are described in the guide Barista Accessories Essentials.
What cannot be substantiated
We did not find: an annual interval for the group gasket in the manuals of the home machines checked, a measurement of the temperature stability of thermoblocks, evidence for the diagnosis “permanent dripping equals a clogged solenoid valve”, a measured value for the milk temperature at which microfoam breaks down, a source for limescale flakes in the intake screen or tank valves that stick after standing, and a failure statistic for deciding between repair and replacement. Statements about the Rancilio Silvia rely on our German review, because the original manual was not available to us; the backflushing intervals for the Lelit Anna and Elizabeth come from the reviews, following the manual. The details of Stiftung Warentest’s 2021 assessment of portafilter machines are behind a paywall that we did not open.