How to Descale a Coffee Machine: Guide for Every Type

The short answer: Descale according to your machine’s manual: for daily use WMF names between one month and six months depending on hardness, Moccamaster every 100 brews, but at least every three months. The product is also in the manual, because vinegar is prescribed by Severin and forbidden by Gaggia and Moccamaster. Our assessment: rinse once too often rather than once too little afterwards, as Stiftung Warentest also advises.

Before you start: five rules for every machine

1. Follow your machine’s manual. durgol writes in the instructions of its descaler that for the descaling and rinsing process the machine’s operating instructions apply first. How far this goes is shown by the Lelit Elizabeth: its 2018 manual forbids, in capital letters, putting descaling agents into the water tank, and the German 2022 manual provides for descaling once a year by a technician, after a condition check by the dealer or a specialist technician. No general recipe for espresso machines with a portafilter can be derived from this.
2. Take out what the manual lets you take out. Philips (AquaClean), Siemens (BRITA Intenza), De’Longhi (DLSC002) and Sage remove the water filter before descaling. On the LatteGo, Philips also has you take out the milk system for descaling and for hot water, and the De’Longhi Dedica wants the portafilter detached.
3. Do not mix anything. In its safety data sheet durgol states that the product should not be used together with other cleaning or descaling agents, and De’Longhi asks in the leaflet of the EcoDecalk not to use any other products not suitable for descaling. That this is more than caution is shown by chlorine. The report “Ärztliche Mitteilungen bei Vergiftungen” (medical reports on poisonings) for the year 2001 (BgVV, predecessor of the BfR, pages 54 and 55) records that chlorine gas forms when an acid is added to a hypochlorite-containing solution, in the household for example when a bleach and a toilet cleaner are used at the same time. The warning on the hypochlorite cleaner described there explicitly counts descalers among the acidic products it must not be mixed with.
4. Do not drink the solution, and wipe up splashes immediately. Philips, Saeco and Gaggia prescribe never drinking dispensed descaler solution. Jura warns of damage to sensitive surfaces such as marble, De’Longhi speaks of sensitive surfaces and durgol of acid-sensitive materials. durgol has you let used solution cool before pouring it away.
5. Rinse more than once afterwards. In 2013 the BfR examined eight brand-new coffee machines (three portafilter, three pod and two capsule machines). One portafilter machine released high amounts of lead especially after descaling, others hardly any, and because of the small number of samples the data are not representative according to the BfR. Where the lead comes from is not known to the BfR: components and possibly solder joints may contribute, and acidic descalers may have dissolved it from metal components. In 2021 Stiftung Warentest found raised lead amounts in two of seven portafilter machines (according to the BfR, with no information on descaling). The BfR advises rinsing well after descaling, repeating the rinse steps specified by the manufacturer, and, at daily start-up, running a rinse step with water only before the actual preparation. In 2013 Stiftung Warentest advised descaling only when necessary and rinsing once too often rather than too little. The yardstick is the number of rinse cycles in the manual. Of the sources we read, only Morgenheld names smell as a criterion, for its moka pot. The measured values from Stiftung Warentest are in the questions at the end.

Descaling a bean-to-cup machine: programme, quantities, rinse cycles

The machine asks you to descale, you prepare it following the five rules and start the programme. On the E6 and the E8, Jura takes three descaling tablets in 500 ml of water. The Saeco GranAroma and the Philips LatteGo 5400 want the whole bottle of Philips descaler up to the CALC CLEAN marking, plus a container of 1.5 litres. De’Longhi puts a 100 ml pack up to fill level A and water up to 1 litre into the tank, for the Dinamica Plus ECAM 370.70 over a container of at least 2 litres. On the Nivona NICR 790, water goes in first up to the 0.5 litre mark and then the descaler, never the other way round, and the programme must not be interrupted. The drip container of the Siemens EQ600 should hold at least 1 litre; for the Melitta CI Touch the manual names 0.7 litres.

The rinse cycles are also up to the manufacturer. Philips and Tchibo run an automatic rinse phase. For the portafilter machine Dedica EC685 and the bean-to-cup machine Magnifica S, De’Longhi prescribes two rinse cycles with the tank filled to MAX, and for the Magnifica a third if the tank was not filled to MAX. Melitta requires two for the AromaFresh X, Moccamaster two to three. On machines with an automatic rinse phase we would additionally run water through once afterwards, because from the outside you cannot tell how often the phase rinses.

First set the water hardness on the machine, because on many machines the prompt depends on it. The scales are not the same: Jura offers 1 to 30 °dH (German degrees of hardness), Philips five levels with the default 4 (hard), Ninja hd 0 to hd 5 with the factory setting hd 5. Philips and Ninja include a water hardness strip. De’Longhi switches the indicator light on after a preset operating time that depends on the hardness. Our conclusion from this: if you enter more hardness than your water has, you get the prompt earlier than necessary.

Descaling a portafilter machine and backflushing

Owners of portafilter machines look after two things: they descale, and they backflush the brew group. Sage separates the two in its own manuals. On the Barista Pro, the FLUSH alarm for the cleaning procedure is expressly not the same as the DESCALE alarm; on the Barista Express Impress, the backflush cycle with cleaning disc of about 5 minutes is not part of descaling.

Descaling: no common recipe

According to the manual (E24), the Gaggia Classic Evo Pro wants to be descaled every 2 months of machine use, with no grading by hardness, and only with Gaggia descaler. The procedure: half a bottle of descaler into the tank, top up with drinking water to MAX, dispense two cups of water each from the steam wand and the brew group, let it act for about 20 minutes with the machine switched off, then continue dispensing and rinsing.

Sage works with its own descaling mode. During this the water tank may be neither removed nor emptied completely; the Express Impress wants the powder in one litre of tap water and rules out bottled water. The Dedica EC685 signals via an indicator light, an interval in weeks is missing, and only De’Longhi descaler is permitted. For the Victoria and the Anna PL41TEM, Lelit provides only natural descaler in the tank, and for the Elizabeth none at all. In the editions of the Rancilio Silvia manual we checked, a chapter on descaling is missing; our German review advises asking customer service for the approved product before the first descaling. For the Gaggia Classic Up, the manufacturer refers to the service centre or dealer if softeners are not enough.

Where the manual is silent on descaling, we would first ask the manufacturer or dealer before putting acid into the boiler (our assessment). Simply ignoring the limescale does not help either: in a safety note (Barista Pro and Express Impress), Sage warns that limescale deposits or a blocked steam wand can cause the portafilter to turn or loosen and release under pressure.

Backflushing: rhythm and quantity

For backflushing, a blind basket sits in the portafilter, cleaner is added, and the pump runs in bursts. According to Urnex, this keeps shower screens and filters free for even extraction.

For household machines the information ranges from daily (Rancilio) through weekly to monthly. On rhythm, three patterns stand side by side: Urnex and Lelit Anna share one, Gaggia and Rancilio have one each (table). On quantity, the range runs from a quarter tablet to a teaspoon. As our own rule for a portafilter machine with no specification: every 100 servings or at the latest monthly, whichever comes first. For soaking the baskets, Urnex names 6 g of powder per litre of hot water for 30 minutes (do not immerse the portafilter handle), Lelit Anna 7 g in hot water for at least 15 minutes.

For its portafilter machines, Lelit (Victoria, Elizabeth) lists a 3-way solenoid valve, Gaggia on the Classic Up a solenoid valve with no information on the type. All three describe backflushing with a blind basket. Our German review of the Urnex Cafiza names such a valve as a precondition.

Descaling a drip coffee machine

For drip machines, too, the specifications are inconsistent. The WMF Stelio Aroma wants a paper filter inserted during descaling, because limescale residues collect in it. The jug is emptied beforehand, after descaling the machine cools down for 5 minutes, and then the tank is rinsed up to the 8-cup mark. On the Severin KA 4810 you first switch off the grinder with GRIND OFF, fill the tank with cold tap water up to marking 10 for the jug and add 80 ml of vinegar essence, and the machine is rinsed afterwards. The Emerio CME 122933 has 400 ml of water with descaler, per the dosing instructions, act for about an hour, then run through, and then water is run through several times; removable parts are rinsed off. The Melitta AromaFresh X shows the need with a permanently red CALC LED, the programme must not be aborted, and afterwards it is rinsed twice with the maximum amount of water without coffee. On the Moccamaster KBG Select, two to three runs with clean water follow the descaler run.

The products diverge just as much. Moccamaster forbids vinegar and biological descalers and recommends Durgol Universal descaler, Melitta recommends its own Anti Calc Liquid for Filter Coffee & Aqua Machines, and for the Textures+ Russell Hobbs requires a descaler from the manufacturer. The Severin has neither an adjustable hardness level nor a limescale filter; the manual only says to descale regularly. A scheme for all drip machines would be invented given such contradictory specifications.

Descaling a moka pot

For moka pots, too, the manufacturers’ leaflets apply, and they are short. The Bialetti Moka Express in aluminium: fill the boiler with water to just below the valve, add two teaspoons of citric acid or vinegar, assemble the pot completely, make espresso without coffee grounds, pour away the liquid and rinse the pot under running water. Against limescale at the valve, Bialetti advises moving the piston along its axis during normal washing. For the stainless steel Venus, the Brikka and the Moka Induction, too, Bialetti names two teaspoons of citric acid or vinegar.

In a blog post of 12 August 2026, Nevo advises, for the stainless steel pot with 6 cups, not descaling to a rigid calendar but according to water hardness and visible need (the signs are in the table of fault patterns). The procedure: check the seal and filter disc, fill the base to just below the valve, add two teaspoons of food-grade citric acid, leave the funnel empty, let it run through on low to medium heat, let it cool, dispose of the solution, rinse thoroughly and do one run with water only. Morgenheld advises against vinegar for its own stainless steel pot: it could make limescale flake, clog the riser tube or attack the stainless steel. Afterwards rinse thoroughly until no smell remains, and dry. Groenenberg and the Rommelsbacher EKO 364 E, an electric moka pot with its own heating element, on the other hand allow citric acid or vinegar. Rommelsbacher advises hot water with citric acid or vinegar in the water container, left to stand for a while, then wiped out and rinsed with clear water.

The manual of the Milu contains no note on descaling. For such cases the Bialetti instructions, with two teaspoons and one run without powder, are the nearest guide (our assessment). For stainless steel, citric acid rather than vinegar would be the more cautious choice, because Morgenheld advises against vinegar there. How to use the stovetop pot otherwise is described in the guide Moka pot guide. Whether it may go in the dishwasher depends on the manufacturer and the material; more on this in the questions at the end.

Descaling capsule and pod machines

In the manuals we read, the manufacturer here mostly sets the procedure including its own product. For the Senseo Original Plus, Versuni prescribes: every 3 months, only a citric acid based descaler for Senseo, no white vinegar and no mineral acids (sulfuric, hydrochloric, sulfamic, acetic acid). The procedure: half a bottle of Senseo descaler to one litre of tap water, two descaling cycles, then two rinse cycles. If the machine stood idle for 12 hours after descaling, one additional rinse cycle is added. For the Senseo Switch, the Philips product page warns that vinegar could cause damage and a loss of taste. The manual likewise excludes mineral-acid based descalers, with vinegar given there as an example, plus sodium-containing water softeners.

Tassimo forbids descaling agents with phosphoric acid. The Tassimo Happy names original descaling tablets TCZ6004; four tablets are enough for two descalings. On the My Way 2, water up to the calc marking and descaling tablets go into the tank (the pictorial instructions show two), and the solution runs into a vessel of 500 ml or more. The tank is then rinsed and the rinse cycle is run four times; it has no weekly interval and no hardness setting. Nespresso counts in cups: in the Krups manual, the Essenza Mini names intervals by hardness and warns that other products such as vinegar could impair the taste. The Vertuo Next descales only on indication, with the Nespresso descaling kit: 0.5 l of water plus one unit of descaling liquid in a container of 1 l.

Why limescale precipitates, and what it does

Total hardness is the sum of the alkaline earth ions in the water, mainly calcium and magnesium (Lexikon der Chemie, Spektrum). For coffee machines, the part that the encyclopaedia calls carbonate hardness (also spelled karbonathärte in German) or temporary hardness counts: on boiling, the hydrogen carbonates of calcium and magnesium decompose, the free carbonic acid escapes, and sparingly soluble carbonates settle as scale. The non-carbonate hardness, bound to sulfate, chloride and nitrate, does not precipitate this way. Both together make up the total hardness. The Lexikon der Geowissenschaften says briefly that carbonate hardness can be removed by boiling.

From this follows, as our own deduction from this chemistry: two waters with the same total hardness can leave different amounts of limescale at the heater, depending on how large the carbonate share is. The range label soft, medium or hard does not reveal the share.

What the layer does is described tersely and without figures by the Umweltbundesamt: limescaled heating elements hinder heat transfer or lead to appliance failure (Umwelttipps, as of 9 April 2024), and a limescale layer raises electricity consumption through hindered heat transfer (leaflet of 2011). The manufacturers are more specific, but also only qualitatively. WMF names longer brewing time, lower coffee quality, energy losses and a reduced service life. Sage lists water flow, brewing temperature, machine performance and the taste of the espresso, Lelit clogged channels and a lower outlet temperature. Tchibo writes that descaling as soon as it is indicated extends service life and saves energy.

Which temperature a drip machine should deliver is set by SCA standard 310-2021 for home drip machines: 90 to 96 °C should be reached in the coffee bed before 33 percent of the water mass has been applied, and afterwards the temperature should stay in the range (section 6.2). It only requires the manufacturer to supply cleaning instructions (6.7). The reference water of the standard has a calcium hardness corresponding to 50 to 175 ppm CaCO3 (0.5 to 1.75 mmol/l, by our own conversion roughly 2.8 to 9.8 °dH), an alkalinity of 40 to 70 ppm CaCO3 and a pH value of 6 to 8 (7.1.4). The reference water serves for appliance assessment; for tap water at home the standard contains no specification.

How much electricity this costs is open. The durgol figure belongs in no calculation: 8.1 percent higher consumption per millimetre of limescale, from internal trials whose measurement conditions are unknown.

Cleaning and descaling are two different processes

Anyone who takes a descaler for a cleaning agent expects something that does not happen. Urnex separates the tasks like this: cleaning removes coffee oils, descaling mineral deposits from the heating elements. durgol gives a chemical reason: grease dissolves with alkaline and limescale with acidic ingredients, the two are not compatible in one product, and a descaler does not remove coffee oils. Conversely, according to Coffeeano, cleaning tablets have no descaling function.

The safety data sheets confirm the alkaline side. According to the data sheet (version 5.0 of 2 February 2026), the Jura 3-phase cleaning tablets contain 25 to under 50 percent sodium carbonate, 10 to under 17 percent sodium percarbonate and 2.5 to under 10 percent each of citric acid and adipic acid; the pH value is 10.2 (5 percent solution, 20 °C). The Coffeeano cleaning tablets name in the data sheet (as of 28 November 2022) sodium carbonate 25 to 50 percent, sodium percarbonate 10 to 20 percent and citric acid 5 to 10 percent. So citric acid is in both, the Jura solution stays alkaline anyway, and both manufacturers list the tablets as cleaners.

On bean-to-cup machines these are separate programmes with separate products. The GranAroma manual lists, among others, three maintenance products from Philips and Saeco: descaler CA6700, coffee oil remover tablets CA6704 and milk circuit cleaner CA6705. The brew group of the Philips LatteGo 5500 gets a coffee oil remover tablet monthly. Jura separates the cleaning programme with a cleaning tablet from the descaling programme, and the Ninja Luxe Pro distinguishes CLEAN with cleaning disc and tablet from DESCALE. Which indicator comes first and what runs afterwards is in the manual of the respective machine; an order for all machines cannot be derived from the sources.

Vinegar, citric acid or branded descaler: what the sources say

The answer depends on the machine, and the manufacturers are split.

The manufacturers give different reasons for the ban. Nespresso and the Philips page on the Senseo Switch name taste; Urnex adds that vinegar is an effective descaler but hard to rinse out, takes longer and leaves smell and aftertaste. Morgenheld names flakes and a clogged riser tube, Nivona sealing rings, though there expressly also for citric acid. In 2003 Stiftung Warentest gave as the reason that vinegar could attack metal and plastic parts. None of the sources we read documents damage to rubber seals or aluminium from household vinegar, and Bialetti expressly names vinegar alongside citric acid for its aluminium pots. Also, “pure vinegar” is not a fixed quantity: vinegar essence contains 25 percent acetic acid, household or table vinegar five to ten percent, edible vinegar typically two to eight (ÖKO-TEST, 4 October 2024, a consumer magazine).

The acids themselves also differ. The dissociation constants (PubChem) give a pKa of around 1 for amidosulfonic acid, 2.79 for citric acid (other tables list 3.13 for the first stage), 3.75 for formic acid, 3.86 for lactic acid and 4.76 for acetic acid. Amidosulfonic acid is thus the strongest and acetic acid the weakest of these acids. How strong the finished solution acts additionally depends on the concentration. For citric acid, Bialetti and Nevo name two teaspoons per boiler. For ready-made products, calculations from our German reviews are available: De’Longhi EcoDecalk, 100 ml with 30 to 50 percent lactic acid to 1 litre, gives roughly 3.6 to 6 percent; durgol, 125 ml with 10 to 15 percent amidosulfonic acid to 1 litre, 1.4 to 2 percent.

One reservation about citric acid concerns its calcium salt, and it weighs little. Calcium citrate exists as a tetrahydrate and as a hexahydrate. Liu et al. (2020, Food Research International) measured in pure water, as total calcium, for the tetrahydrate, which is the stable form above about 52 °C, 3.46 mmol/l at 70 °C and 2.77 mmol/l at 90 °C. The hexahydrate, stable below that, dissolves at 25 °C with 3.14 mmol/l and better with rising temperature (4.25 mmol/l at 90 °C). The difference between hot and cold is thus small, and the direction depends on the hydrate. The calcium salt of acetic acid, calcium acetate, on the other hand, dissolves well: 37.4 g in 100 ml of water at 0 °C and 29.7 g at 100 °C (HSDB via PubChem). This does not document any machine damage. On temperature, the manuals go separate ways anyway: Sage has the tank filled with hot tap water, Severin requires cold water (drip machine, see above), Rommelsbacher hot water with citric acid (water container, see above).

On branded descalers, WMF writes that suitable products contain inhibitors that protect seals and surfaces, cause no other deposits and are neutral in taste. A comparison comes from the Swiss consumer magazine Saldo, reported by test.de on 21 October 2020: all ten universal descalers removed limescale, but to different degrees, the strongest about 5,600 mg in 10 minutes, the weakest 2,200 mg. Silicone survived 24 hours in undiluted descaler undamaged, chromium steel mostly changed colour after contact with undiluted descaler. A coffee machine does not need an expensive special descaler, cheap universal products are enough. Citric acid and vinegar do not appear in the visible test.de text. In the 2013 chat, Stiftung Warentest said that inexpensive standard commercial descalers are usually enough.

The active ingredients of ready-made products also contradict each other. Philips and Senseo exclude sulfamic acid based descalers in their manuals, whereas durgol swiss espresso contains 10 to 15 percent amidosulfonic acid (pH below 1) and, according to test.de, Jura, Nivona and Siemens base their products on it. De’Longhi relies on lactic acid for the EcoDecalk, 30 to 50 percent according to the US safety data sheet. Sulfamic acid and amidosulfonic acid are the same substance, so Philips and Senseo exclude what other manufacturers base their products on.

Our assessment: the machine’s manual comes first. Where there is no specification, for example with a stovetop pot without a leaflet, we consider diluted citric acid the defensible household remedy, because the Verbraucherzentrale calls it no problem for coffee machines, and Stiftung Warentest called organic descalers on this basis mostly allowed back in 2003. We would use vinegar only where the manual permits it.

How often you descale: hardness, manufacturer values, assessment

Your water hardness is known to your supplier. According to the Umweltbundesamt, it tells the household one of the three ranges soft, medium or hard and supplies the analysis on request; the Verbraucherzentrale likewise refers to the supply company. According to the UBA, the hardness of local drinking water practically never changes, so a range once determined continues to apply. Some machines include a water hardness strip (Philips, Jura, Ninja, De’Longhi, Siemens).

The German Detergents and Cleaning Products Act (Wasch- und Reinigungsmittelgesetz, § 9, applies in Germany) knows three ranges and calculates in mmol calcium carbonate per litre, not in degrees of German hardness. With 1 °dH equal to 10 mg/l calcium oxide, i.e. 0.1783 mmol/l (own calculation with the molar mass 56.08 g/mol, according to the Lexikon der Chemie), the limits are 8.4 and 14.0 °dH. In its manual WMF gives 1 °dH as about 0.18 mmol/l. Others divide differently: WMF has four levels with the limits 7, 14 and 21 °dH, the Verbraucherzentrale names soft as 0 to 7 °dH (hardness range I) and hard as 14 to 21 °dH (hardness range III), the Lexikon der Chemie names limits at 4.2, 8.4, 16.8 and 28 °dH. Which scale your machine uses is in its manual. On this page the law applies.

The last column has no source: these are our own settings for a machine without a counter and without an interval in the manual. Where an indicator or the manual gives an interval, it takes precedence. Compared with the manufacturer values below, they are chosen rather short. More often is not automatically better, as the fifth rule above shows.

The range runs from monthly to six months, and the way of counting differs just as much. Jura and Ninja prompt based on the set hardness, De’Longhi after a hardness-dependent operating time, Sage Creatista after servings, Nespresso after cups. Brewed litres are thus only one of several counting units. With hard water around 20 °dH, Nespresso (12 litres) and Sage Creatista (60 litres from 14 to under 21 °dH, 40 litres from 21 °dH) are three to five times apart (our conversion): the manufacturers vary more than the hardness ranges explain. Besides the quantity, a time limit can apply, as the Moccamaster row shows, and filters bring their own deadlines (section on water filters). Programme-controlled bean-to-cup machines calculate themselves, so on them the indicator usually sets the pace. Exceptions are the Melitta CI Touch without water filter (every 3 months) and the Tchibo Esperto mini with long heating (see the table of fault patterns).

Fault patterns: how to recognise limescale, and what is something else

For steam at the valve, we would start with the water level and the amount of powder, because both can be changed immediately and at no cost (our assessment).

The milk system: hygiene instead of limescale

Stiftung Warentest (27 July 2026, freely visible part) advises rinsing the milk system after every cappuccino or latte macchiato and, despite automatic programmes, taking the individual parts apart by hand according to the operating instructions and cleaning them thoroughly, otherwise germs may form. According to Stiftung Warentest, many providers recommend rinsing the removable brew group under running water about once a week; with a fixed brew group a cleaning programme takes over. Warentest counts emptying the coffee grounds container and the drip tray as part of daily care.

How often it is taken apart is regulated by the manufacturers per model. The De’Longhi Dinamica Plus ECAM 370.70 wants the milk container taken apart and cleaned every two days, the 380.95 reminds you weekly of the thorough milk jug cleaning: soak for at least 30 minutes in water of at least 40 °C with detergent, or put it in the upper basket of the dishwasher. The De’Longhi safety booklet names for the carafe for hot milk a maximum of 2 days, for cold milk a maximum of 1 day in the fridge, after which it is emptied, taken apart and cleaned. There you clean the water tank every 30 days, and you change the water for hot drinks at least every 3 days.

On the LatteGo, Philips offers no automatic cleaning of the milk system. According to the Philips product page it consists of two parts without tubes and, according to the manufacturer, is dishwasher safe. As cleaning time under running water Philips names less than 10 seconds for the LatteGo of the 5500 series and, on the product page, 15 seconds for the 5400. According to Philips, a defect or mould can occur without cleaning and maintenance, the repair is then excluded from the guarantee, and in case of mould it should be cleaned more often. On the steam wand of a portafilter machine, according to Sage you wipe the nozzle immediately with a damp cloth and free it of milk residues with a few bursts of steam. Rancilio has the steam tap immersed in milk cleaning solution, heated up and left to act for at least 10 minutes. How the wand is guided when frothing is in the guide How to froth milk.

Water filter instead of descaling?

The manufacturers’ promises are not comparable. For the AquaClean CA6903/22, Philips advertises “up to 5,000 cups without descaling”, but only after eight filter changes and only with the AquaClean sticker on the tank, and you should change at least every 3 months or on prompt. Jura writes that with the CLARIS Smart+ cartridge the prompt to descale does not apply on the E6 and E8 (on the E8 the manual no longer prescribes descaling at all; on the E6 it additionally names a tank descaling with tablets from time to time); the capacity is 65 litres for 1 to 5 °dH and 40 litres for 26 to 30 °dH. The Siemens BRITA Intenza should be changed after 50 litres or after 2 months at the latest; with the filter, descaling is needed less often, without a figure, and “five times less often” appears only on Amazon. For the De’Longhi DLSC002, the manufacturer names about 2 months, with idle periods at most 3 weeks, and the US page says that each fresh filter means descaling about 20 percent less often. Sage names for the Barista Touch every 3 months or 40 litres (at hardness 2 up to 60 litres), for the Barista Pro, Barista Express Impress and Bambino Plus only every 3 months, and Lelit recommends the resin filter in the tank.

Between “does not apply” at Jura and “about 20 percent less often” at De’Longhi there is too much to extend the calendar across the board. Our assessment: follow your machine’s indicator and look up the filter in the manual.

Guarantee and third-party products

Several guarantee terms tie the claim to care and products. In point 3 of its guarantee terms, Jura writes: if operating or maintenance instructions are not followed or care products other than JURA water filters, JURA cleaning or descaling tablets are used that do not meet the original specifications, any guarantee lapses. At De’Longhi, unsuitable descalers or irregular descaling can cause defects that are not covered by the manufacturer’s guarantee (Dedica EC685, La Specialista, Classic EM450, Dinamica, Rivelia). Melitta lets the guarantee lapse for consumables outside the original specification, WMF denies the claim in the case of an unsuitable product or disregard of the descaling instructions, Moccamaster excludes damage from unsuitable cleaning or descaling agents.

Philips does not let the guarantee apply in case of poor maintenance; on the LatteGo 5400 you also risk it, according to the manual, by omitting descaling (the German sentence is ambiguously worded). Gaggia excludes repairs after neglected cleaning and descaling. Bialetti (Moka Express, Brikka, Moka Induction) and Milu list limescale deposits among the exclusions, and Russell Hobbs requires a repair fee for returns within the guarantee period whose defect is due to limescale deposits. Anyone who wants to use a third-party product during the guarantee period should first read their manufacturer’s terms.

What cannot be documented

Several answers one expects from a descaling guide are not supported by the sources.

• How accurate water hardness strips are, we found no source from an authority, standard or consumer organisation. Only the route via the supplier is documented.
• Whether the supplier’s analysis states the carbonate hardness, we have not checked.
• A dosage for citric acid in grams per litre is given by none of the manufacturers we read. There is also no primary source for the price per use, so we name none.
• A comparison of citric acid, vinegar and amidosulfonic acid on coffee machines (limescale-dissolving capacity, rinsability, materials) is not available to us, nor is a measurement of the inhibitors that WMF attributes to suitable descalers, or a measurement of whether calcium citrate precipitates in a descaler solution in the machine.
• On the service life of machines with and without regular descaling, on heating time and extra consumption due to limescale, and on how many households descale too rarely or with the wrong products, we found no independent data. That descaling extends service life is therefore stated in the text only as a manufacturer claim (Tchibo, WMF).
• Whether backflushing harms or does nothing on a portafilter machine without a 3-way solenoid valve is stated by no manufacturer source we read.
• The standard DIN/IEC 60661 for electric household coffee machines and the SCA Water Standard (a different document from the SCA standard 310-2021 for home drip machines cited above) are not available to us in full text. Standard 310 contains no descaling rule and does not document that limescale shifts the temperature window of 90 to 96 °C.

Which products from our catalogue come into question

Prices according to the price box of each German review, as of September 2026, on Amazon.de; for Urnex and EcoDecalk the review gives no date of its own. The rating is our editorial assessment and not a measurement result.

Calculated per use from the prices in our German reviews: EcoDecalk about €1.60 (500 ml for five uses), durgol about €3.45 with one bottle per descaling (four bottles of 125 ml) and double that for a tank over 1 litre, the Jura tablet about €1.67, the Coffeeano tablet about €0.16. The maximum amount of 3 g of Urnex powder gives, from 566 g, a calculated good 188 backflushes, so about 7 cents per procedure.

According to our German review, the durgol swiss espresso is not intended for drip machines and kettles and, by editorial assessment, is unsuitable for aluminium moka pots. How hardness influences taste is covered in the guide Water hardness and coffee, and which machine suits you at all is covered by the buying guides for bean-to-cup machines and portafilter machines. A price calculation is worthwhile only where the manual leaves the choice, for example with Bialetti, Groenenberg and Rommelsbacher with citric acid or vinegar.