Breville Dual Boiler (BES920XL) Review

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#1: Post by RapidCoffee »

The Breville BES920XL is a feature-laden, attractively-priced double boiler espresso machine designed for the prosumer market. Like most Breville products, the BES920XL is an aesthetically pleasing home appliance, with a high SO acceptance factor. It is sized appropriately for most kitchens, and fits neatly under standard countertops. Those with overhead cabinets who wish to use the cup warmer will have to make other arrangements.

Breville was kind enough to furnish a loaner espresso machine to Home-Barista for review purposes. The loaner machine was completely stock, other than the inclusion of a bottomless portafilter. The BES920XL (along with its predecessor, the BES900XL) are often referred to by the BDB (Breville Dual Boiler) acronym.

BDB ergonomics are, quite simply, outstanding. There is an impressive attention to detail at all levels. For example, rather than legs, the espresso machine sits on retracted wheels. Under the drip tray is a lever than allows you to lock the front wheels up, so the machine stays in place. For minor adjustments, tilt the machine back slightly, and you can roll it on the back wheels. Little touches like this make a big difference in user friendliness.

Unlike most espresso machines, the BDB provides the ability to easily drain the boilers. This is a great feature for descaling and shipping. At the lower right of the front panel are two screws (normally hidden under a rubber cover) which, when loosened, drain the boilers into the drip tray. Kudos to Breville for implementing a feature that really should be available on all espresso machines.

Other welcome ergonomic touches include a small storage area under the drip tray, the ability to refill the water reservoir from either the front or back of the machine, and a cute popup float that warns you when the drip tray should be emptied.


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#2: Post by RapidCoffee (original poster) »

Unpacking and setup

The BDB was double boxed, shipped FedEx, and arrived in new condition. The machine was well packaged, cradled in fitted styrofoam padding. Unpacking and initial setup took under half an hour. Kudos again to Breville on the excellent packing and easy-to-follow setup instructions.

Setting up the machine is straightforward: clean the water reservoir, portafilter, baskets, tamper, and milk pitcher. Rinse and install the water filter in the water tank. Fill the tank and turn on the machine. Set the water hardness level. Breville includes a water hardness test strip, and my bottled water measured at the default hardness setting of 3. Turn on the machine, and allow the vibratory pump to run for about one minute to prime the system. The boilers come up to temperature in under 10 minutes. Flush the machine by running water through the brew group, the hot water tap, and the steam wand a couple of times. That's it; you're ready to pull a shot.


Catering to both the experienced and beginner espresso enthusiast, Breville includes two pairs of single/double baskets. One pair are standard baskets, the other are restricted (pressurized) baskets. The latter type of basket make the best of stale or too coarsely ground coffee and are eschewed by more experienced baristas; Is it possible to pull a real espresso from a pressurized portafilter? elaborates on this point. Breville also includes a tamper that conveniently stows in a slot next to the grouphead via a magnet in the top of the tamper handle. Unique among espresso machines manufacturers, Breville truly includes all the accessories you'll need to get started.

Pitcher, single & double baskets, tamper, standard and bottomless portafilter (optional)

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#3: Post by RapidCoffee (original poster) »

Brew temperature

At the heart of any espresso machine is the ability to deliver water to a puck of coffee grounds at 9 bars of pressure at a consistent, relatively stable temperature. For cappuccino lovers, the ability to produce latte-art quality microfoam is equally important. The Breville Dual Boiler delivers on all counts.

As shown in the following diagram (courtesy of Breville), there are three distinct heating systems in the BDB: a 100W grouphead heater (#3), a 700W brew boiler heater (#2), and a 900W steam boiler heater (#1). Water is heated to steam temperature in the steam boiler. This temperature is adjustable via the digital menu. In order to avoid temperature fluctuations from cold water injection, brew water is preheated by passing a portion of its inlet tubing through the (stainless steel) steam boiler before arriving at the (stainless steel) brew boiler. The grouphead itself has a heating coil (#3), further improving temperature stability.

Heating elements in grouphead (#3), brew boiler (#2), and steam boiler (#1)

This "hat trick" of heating systems yields excellent brew temperature stability and very rapid warmup times. Electronic temperature controllers on the brew boiler and grouphead heater deliver the desired brew temperature with precision. Breville suggests waiting 15 minutes for the system to come up to temperature from a cold start; I found this to be more than adequate.

The BDB features dual vibe pumps: a 15 bar Ulka (for brewing) and a 4.5 bar Ceme (for filling the steam boiler). These pumps are reasonably quiet (for vibe pumps) and appear to function properly. The additional low pressure pump allows the steam boiler to be refilled without affecting brew pressure during an extraction.

Brew pressure

Unfortunately, there is no easy way to adjust brew pressure. This is clearly a deliberate design decision by Breville. My BDB arrived with the brew pressure set to 10 bars, a bit on the high side. Rather than fiddling it down to 9 bars, I chose to live with it.

Interested hobbyists may consult this web site ( for instructions on how to adjust the OPV.

Digital Menu

The BDB has a well-laid-out digital menu system that allows the user to monitor and modify various machine settings. These settings include brew boiler temperature, steam boiler temperature, and preinfusion time.

The default machine settings work reasonably well across the board. The brew temperature of 200F is a good starting point for most espresso blends. The steam temperature of 175F produced slightly anemic steam velocity, so I eventually bumped it up to 180F for faster milk steaming. The default settings for preinfusion (6 seconds, 60% pump pressure) and brew time (30 seconds) are also good generic choices. All these settings (and more) can be changed via the menu.


As seen in the opening photo, the BDB controls include:
  • Power button (left front panel).
  • Brew buttons on right front panel (MANUAL, 1 CUP, 2 CUP). The single and double cup buttons are programmable.
  • Steam dial/lever on upper right side of machine (LED on front panel).
  • Hot water dial on upper left side of machine (LED on front panel).
  • Brew boiler pressure gauge in center of front panel.
  • Digital display with four control buttons on front panel.
The digital display is used for programming the machine (brew temperature, shot duration, preinfusion, auto start, etc.). There are a wide range of options - far too many to list in this review - but the menu system is nicely laid out and easy to use, and the options are adequately described in the manual.

The digital display presents the various settings (brew temperature, shot timer, etc.). It informs you when the water reservoir needs refilling, and when it is time for maintenance.

Friendly maintenance reminder

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#4: Post by RapidCoffee (original poster) »

Espresso Machine Comparisons

I compared the BDB with two other espresso machines: Gaggia Baby and La Spaziale Vivaldi S1. The dual boiler BES920XL currently retails for $1300, similar in price to several low-end HX machines. The Gaggia Baby is a mid-level single boiler espresso machine with a list price of $600 (street price $350), and is distinguished from entry-level Gaggia models by a three-way solenoid valve. The Spaziale S1 is a fully plumbed, rotary pump, dual boiler, single group commercial machine with a list price of $3000 (street price $2300).

The grinder used in all tests was a Mazzer Robur (doser model). Coffees for testing were generously supplied by Counter Culture Coffee (Apollo, Rustico, and #46) and Bodka (Main Squeeze). Other coffees included Mountain Air African Espresso blend and Metropolis Ethiopian Gelana Abaya SO. Coffees were ground with a bean load in the hopper, and doses were weighed to the nearest 0.1g. WDT was employed to ensure good grinds distribution.

I experimented with a wide range of doses, brew ratios, temperature settings, and shot times on the BDB. For comparison purposes, I used the same grind on different machines, with a "normalized" dose (~18g for 58mm double baskets and ~15g for 53mm double baskets), target brew ratio (67%), and shot times (25-30 seconds).

Forty-Six espresso blend by Counter Culture Coffee, pulled on BDB

A bottomless portafilter was used exclusively on the BDB and S1. I do not have a Gaggia BPF, so a spouted portafilter was used on the Baby. The unpressurized (single wall) 58mm BDB double basket was used for all extractions on the BDB and Gaggia, and the 53mm Spaziale double basket was used on S1 extractions.

Manipulating extraction parameters

All three machines are capable of extracting an excellent shot of espresso. However, there are obvious differences in usability, consistency, and ability to tweak extraction parameters. As you might expect, the Gaggia comes up short in this comparison test. Other than dose and grind, you can only manipulate shot duration. There is no direct method for manipulating brew temperature, although experienced users may experiment with temperature surfing.

The S1 allows you to adjust brew boiler temperature in 1C increments. The S1V1 controls were designed by a sadistic alien, bent on sapping the will of Earthlings by creating the most confusing user interface possible. (Fortunately this has been improved in the S1V2.) An aftermarket mechanical progressive preinfusion chamber adds E61-style preinfusion. You must open the machine and physically install this aftermarket device, a nontrivial procedure.

The BDB menu system allows easy and intuitive adjustments to brew temperature in 1F increments. You can adjust the duration of preinfusion, and even adjust the amount of preinfusion pressure (as a percentage of full pump pressure).


The Gaggia Baby, although capable of excellent extractions, clearly shows its limitations when compared to the double boiler machines. The small boiler (3.5oz) and lack of brew temperature adjustment resulted in one-dimensional flavor profiles and the least interesting shots. Milk-based espresso beverages are always problematic with single boiler dual use (SBDU) machines, and the Baby is no exception.

The BDB and S1 offer stable brew temperatures, plus the ability to manipulate brew temperature precisely and reproducibly. This translates into a full range of flavors in the cup, and a greater realization of the potential of a given roast. Dual boiler machines generally excel at milk-based espresso beverages, allowing you to pull the shot and froth the milk simultaneously.

Comparison tasting between the BDB and S1 generally resulted in small but discernable differences in the cup. This may be attributed to basket size (58mm vs. 53mm) and shape differences. In general, the BDB extractions showed slightly more sweetness, clarity, and separation of flavors than the S1 pours. The S1 extractions were thicker, richer, with better mouthfeel. Neither was demonstrably superior. Both machines clearly highlighted the varietal characteristics of the coffee.

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#5: Post by RapidCoffee (original poster) »

Preinfusion sidebar

Preinfusion is generally considered to provide a positive contribution to espresso extractions. Starting the shot at lower pressure (preinfusion) allows the puck to saturate evenly with water, thereby reducing channeling and other factors that can lead to a poor extraction.

My feelings towards preinfusion have changed since acquiring a very high-end grinder (Mazzer Robur) and the La Spaziale S1. The S1, unlike ubiquitous E61 espresso machines, does not preinfuse the puck. On the contrary: the rotary pump ramps up to full pressure very quickly. Nonetheless, it produces excellent shots. In fact, based on visual appearance, it is easier to get a "pretty" bottomless pour from the S1 than the BDB. (This may be due to differences in baskets.)

Chris Coffee Service sells an aftermarket manual preinfusion device for the S1 that I installed for this review, providing progressive preinfusion similar to an E61 group. This preinfusion device changes the pour characteristics, but does not necessarily improve the taste of the extractions. In keeping with Occam's Razor (simpler is better), I generally run my S1 without the preinfusion device installed.

Back to the Breville dual boiler, which has programmable preinfusion. The menu system allows you to adjust both duration of preinfuson, and pump power during preinfusion (down to 55% of the peak power). Manual control over preinfusion is simple: press and holding the MANUAL button to preinfuse, and release the button to begin full pump pressure. This permits easy experimentation with preinfusion. Again - and I know this goes against the established norm - I did not find that preinfusion improved extraction quality, either visually or in the cup.

Steaming milk
Because latte art quality microfoam is easy to obtain from the BDB, but somewhat slow, it gets mixed reviews from cappuccino and latte lovers. As noted earlier, all three comparison espresso machines (Gaggia Baby, Breville Dual Boiler, La Spaziale S1) can produce good espresso shots. But there is a big difference between the machines when it comes to milk-based espresso beverages.

The Gaggia Baby, like all single boiler espresso machines, is marginal for making even one milk-based espresso beverage. You must decide whether to pull the shot first, and then let it sit while the boiler heats up to steam temperature for milk frothing; or steam the milk first, and let it sit while the boiler stabilizes at brew temperature so you can pull the shot. This results in a classic "damned if you do, damned if you don't" situation, which rapidly becomes unmanageable when making multiple beverages.

The S1, on the other hand, is a steam demon. Frothing 4 ounces of milk takes under 10 seconds; smaller quantities of milk are a challenge. Multiple milk drinks are no problem; you can bang out one latte after another, steaming up to 8 ounces of milk while you pull the shot.

The BDB takes 25-30 seconds to steam 4 ounces of milk. Even after bumping up the steam boiler temperature (the menu allows adjustments from 265-285F), the BDB always took over twice as long as the S1 to steam equivalent volumes of milk. The steam wand itself is nicely designed, the lever/dial allows good control over steam, and it is easy to produce good, latte art-quality steamed milk. However, due to the somewhat anemic steam power, I would hesitate to recommend this machine to "big gulp" latte lovers.

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#6: Post by RapidCoffee (original poster) »

  • appearance, size, weight
  • ergonomics, ease of use
  • multitude of features, good default settings
  • fast warmup time (usable in under 10 minutes)
  • double boiler => brew and steam simultaneously
  • 3-way valve (no portafilter "sneeze")
  • 58mm group head
  • accessories included: 4 baskets (plus blind insert), decent tamper, milk pitcher
  • convenient water reservoir (fill in back or front) with integrated water filter
  • digital temperature display, shot timer, etc.
  • brew pressure gauge
  • "intuitive" digital menu to set brew temp, shot time, preinfusion, etc.
  • easily adjustable preinfusion
  • good manual
  • warning when water reservoir needs to be refilled, drip tray needs to be emptied, cleaning (backflushing), descaling, etc.
  • built-in cleaning/descaling protocols
  • hot water comes from brew boiler, not steam boiler
  • easy to clean and maintain
  • 2 year warranty
  • lack of easy brew pressure adjustment
  • steam pressure on the weak side
  • unknown reliability
Wish list (this reflects my personal biases)
  • brew pressure adjustment
  • more powerful steam boiler
  • rotary pump option
  • direct water line/plumb in option
  • bottomless portafilter
  • "standard" 58mm portafilter (Breville group head requires proprietary lugs)
  • extra unpressurized double basket (single baskets are used seldom, pressurized baskets never)
  • digital scale (instead of semi-useless "Razor" tool)
  • several hardness test strips (one is nowhere near enough)
  • Dimensions: 16W X 15D X 15H (in) = 41W X 38D X 38H (cm)
  • Weight: 30lb = 13.6kg
  • Power: 1700W
  • Cup Clearance: 4in = 10cm
  • Brew Boiler: 10oz = 0.30L (700W)
  • Steam Boiler: 32oz = 0.95L (900W)
  • Reservoir Volume: 84oz = 2.50L
  • Warm Up Time: 8m 20s
  • Boiler Material: Stainless Steel
  • Case Material: Plastic with Metal Finish

The Breville 920XL is an impressive new offering in the prosumer espresso market niche, providing an attractive, ergonomic, feature-laden double boiler machine at an unprecedented price point. The BDB is a pleasure to use, and delivers excellent performance where it counts the most: in the cup. The only negative factors are slightly anemic steam power, lack of brew pressure adjustment, and unknown reliability (largely mitigated by an excellent two year warranty).

Am I ready to part with my S1, in favor of the BDB? No - I would miss the powerful, quiet rotary pump, the convenience of a fully plumbed machine, and the generous steam power of a commercial machine. Would I be happy with the BDB? Absolutely.

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#7: Post by uscfroadie »


Great job on the review. I just wish you would have kept it longer to play with pressure profiling so you could re-evaluate your thoughts on it versus the big plumbed-in Vivaldi with line-pressure pre-infusion. A more fair espresso comparison would have been a Mini Vivaldi versus the Breville double boiler.

Here is a demonstration of the profiling capability. This is just a demo of how you control the pressure, not how to pull the best shot.


#8: Post by estern »

uscfroadie wrote:Here is a demonstration of the profiling capability.
Very cool video. Looks like it is with a 900xl? Unfortunately, this seems not to work on the 920xl. I could be missing something, but I think they've added an auto shut off to the shot when the hot water dial is turned on.
RapidCoffee wrote:The Breville 920XL is an impressive new offering in the prosumer espresso market niche, providing an attractive, ergonomic, feature-laden double boiler machine at an unprecedented price point.
RapidCoffee, thanks for the review. I've been waffling between a lot of options for a machine upgrade. Your post made me take another look at the Breville, and I ended up pulling the trigger. Very happy so far. I'm getting tastier shots than I was on my Gaggia Pure and better quality milk. Significant ease of use improvement also.

In terms of steam power, in my limited experience thus far, I notice a big difference based on warm up time. I haven't found a way to monitor steam boiler temp, but suspect it takes a decent amount longer than the main boiler. Huge difference in quality and speed setting the machine to turn on 30+ minutes before I wake up versus turning it on as I start making breakfast, even though the main boiler temp gets to 200 within minutes.

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#9: Post by old442 »

estern wrote:Very cool video. Looks like it is with a 900xl? Unfortunately, this seems not to work on the 920xl. I could be missing something, but I think they've added an auto shut off to the shot when the hot water dial is turned on.
The 900 stops the shot when the water tap is opened. The key is to not open it far enough to trip the microswitch. Watch the video and you'll see the water tap LED never comes on.

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#10: Post by samuellaw178 »

It's cool to be able to pressure profile, but wouldn't it be sucking off the heat and affecting the temperature stability?