Lever (Leva) Extraction
LLever espresso extraction was a technology pioneered by Achilles Gaggia in 1938. The technological advance saw only a 12 year span of production (various manufacturers ) until the pump was introduced in the 50s.
Many companies followed suit and most of those companies would design their lever machines to draw water directly from the boiler in order to extract coffee. Subsequent technologies saw the introduction of the pump and in later years (60’s) took coffee machine technology one step further with the development of heat exchanger systems that would draw freshwater (for brewing coffee) independent of the primary boiler. The notion of freshwater and greater oxygen content in the water developing better coffee extraction has always been challenged and whether or not more oxygen in the brew water yields different brewing results. There still exists no conclusive evidence of this theory.
Despite the LEVA’s 12 year initial production span and the introduction of modern pump driven technology in espresso extraction, many southern Italian republics (provinces) continue to prefer the use of lever extraction espresso machines for a number of reasons. One, is the fact that it has a low cost of maintenance. Secondly, lever technology brews a particular style of coffee that has become synonymous with those regions for the following reasons.
- Lever Extraction does yield far more rich and deeper espresso flavour.
- It’s well understood, that lever extraction generally derives a sweeter and softer extraction.
Why does lever extraction deliver a richer, deeper, sweeter and softer espresso extraction?
To understand why lever extraction delivers these results, one must first understand some key fundamentals to espresso coffee extraction and how they impact the lever group throughout the brewing cycle. Let’s Consider these three fundamental aspects of espresso coffee extraction: Pre-Infusion. Temperature. Brewing & Water Flow.
Pre-Infusion. Lever Espresso machines have a preset amount of water delivery that can be moved through a
typical bed of coffee when The portafilter is locked in to the LEVA group.
The action of drawing the lever down opens up a valve in the group that allows water kept up
between 112°C up to 118°C to be drawn into the brewing chamber from the boiler. ( Some
residential machines do use a Heat Exchanger and those temperatures are going to run closer
to 95°C and in those cases the brewing chamber receives thermal assistance with the
introduction of a small heating element. ) It’s this initial downward action in the first part of the
brewing process when operating a lever that actually provides the pre-infusion to the coffee
bed. There are Varying thoughts of how long the pre-infusion process should be allowed to
endure before the counter action of releasing the lever moves the cycle in to the actual brewing
process where downward pressure is exerted on the coffee bed. Certainly the longer that the
pre-infusion cycle is allowed to stay in contact, the more that you run the risk of over extracting
At CaffeTech Canada We sell a variety of commercial and residential lever extraction machines, but we do have a philosophy on minimizing the pre-infusion cycle so to stay away from over extraction. We consulted coffee Roasting professionals ( ACE ) that Also concurred the same philosophy.
Remember that when we are brewing coffee at a much higher temperature it is therefore, very critical not to keep pre-infusion with such high temperatures for prolonged periods of times as there is a greater risk of burning the espresso coffee.
The counter action and release of the lever is then going to move us to the next stage of extraction and pending what you did in the pre-infusion cycle is it going to significantly vary the final outcomes of coffee once the extraction process begins.
Temperature. And so we know that coffee entering the brewing chamber on a lever extraction machine, will enter between 112°C to 118°C. when the pre-infusion starts. So then what exactly is occurring after the stage when we release the Lever to set the calibrated spring off to create the brew pressure ?
Firstly, it’s important to note that lever extraction coffee uses massive forged brass groups with extreme thermal stability in order to maintain temperature. We’ve seen the introduction of massive groups like the E61 group In order to maintain temperature stability and in some cases like the LaMarzocco Brewgroup we see the introduction of saturated brew group technology to achieve similar results. Therefore, we know that temperature stability throughout the brewing extraction is common knowledge for great brewing results.
Lever groups need to consider temperature stability even far more than there more contemporary espresso machine designs- and this is because we need to hold the coffee water in the brew cylinder for at least 38- 45seconds. This is generally the amount of time required to extract the coffee on a lever machine and during that period of time there exists no assistance of heat to the group brew chamber. Therefore, during that brewing interval the coffee will need to brew and extract in the chamber and yet maintain an adequate level of temperature stability to derive a decent espresso shot.
Although the brew water initially sent into the brewing piston chamber care of the prison fusion process will range between 112°C to 118°C, The temperature of the water through the brewing process is closer to between 92°C and 96°C, A temperature more consistent with what we can expect in conventional machines with more modern brew groups and rotary pumps . This brewing temperature is further maintained because of the Lever groups mass and construction. Furthermore it’s getting heat assistance from the boiler , counteracting steam pressure (1.2-1.5 Bar) onto the brewing water throughout the process.
In summary, temperature throughout a lever extraction begins at a higher temperature in the pre-infusion stage(112°C to 118°C ) and a continual lowering of temperature ( 96°C to 92°C) during the brewing process - truly a perfect environment for espresso brewing.
Brewing & Water Flow. So once the spring lever is released and the brewing extraction starts, the dispersion screen releases water from the piston chamber into the portafilter. It’s important to note that most high quality lever extraction machines come with a deeper portafilter handle ; generally at 53 mm versus the standard 58 mm group on a pump driven machine. Generally speaking the air chamber above the coffee bed is much larger allowing for the excess pressure from the spring release to be absorbed and additional water flow to be received as the coffee becomes agitated in the portafilter and starts the brewing process . It’s this design to get maximum flow rate and initially higher pressure ( say between 12-13.5 Bar) That differentiates Leva extraction and delivers a very heavy body espresso. This initial stage of brewing is where we see more bitter components of the espresso brew develop.
What then occurs through the next stage of the extraction process ( between 38-43 seconds) is a counter-play of water temperature slowly decreasing as the spring lever decompresses ( elongates ) and subsequently lowers the pressure exerted on the coffee bed towards the end of the brewing cycle. All along as the infusion valve remains open and the lever spring is counteracting with a decreasing water column action (1.2 - 1.5 Bar) forcing the water down onto the coffee bed as the lever group returns to its resting position.
The Assertion, at least by CaffeTech Canada estimations is that it’s this initial ramping of pressure when the coffee is less saturated coupled with the initial higher temperature during and shortly after the pre-infusion cycle that develops a stronger and deeper extraction within the first 10 seconds. Such extraction would never occur on a basic pump driven espresso machines. What’s also occurring at this time while the infusion valve Is still open during the extraction process, is that the boiler pressure is also assisting to drive the water pressure/ flow /temperature in a downward force care of the steam pressure in the boiler - forcing it in the direction of the coffee bed.
Continuing through the extraction process, and as the temperature lowers and the pressure decreases you end up with a much Sweeter, thicker and richer cup of espresso coffee. The last components of the extraction would be much sweeter ( potentially more acidic ) amalgamating the early components of the extraction for a much more harmonious espresso. At Caffetech Canada , We further assert that the softening of temperature and pressure at the end of the cycle when the coffee bed is more agitated would result in a gentler extraction minimizing astringent flavour compounds during this stage.
Once the final extraction has concluded and the lever has returned back to its resting position then the the infusion valve would have closed leaving the remaining coffee bed compacted back into the handle Leaving behind a dry puck. The portafilter at this point could then be removed.
Unlike pump driven machines, where the interruption of the pump finishes the cycle, lever extraction machines require the user to interact with the volume of coffee required. If volume accuracy is required then we recommend the use of a weight scale in order to determine the exact weight desired in your final outcome of coffee. Obviously, this is less important for the home user and certainly paramount for a commercial coffee bar operation.
Advantages Of Lever Espresso Machines
- Less Expensive To Maintain
- Less Group Maintenance
- Better deeper flavour espresso extraction
Disadvantages Of Lever Espresso Machines
- Initial Learning curve on use can be challenging
- Some models do draw water from primary boiler ( see comments above)
Caffe Tech Canada Lever Machine Recommendations
With the above information giving us a good overview of Lever machines, Caffe Tech Canada highly recommend that those considering a lever machine, look at one of the following products as excellent choices for producing top quality espresso shots. We have thousands of espresso machines, and hundreds of lever machines, and the choices below never disappoint.
PROFITEC PRO 800 LEVER ESPRESSO MACHINE $4249
Coming in at Number One as Our Top Lever Espresso Machine is the Profitec Pro 800. True to the quality expected from a German Manufacturer, the Profitec Pro 800 uses a 58 mm Brewing group and Stainless Steel construction as well as a massive 3.5 Ltr Insulated Copper Boiler for impressive Steam capacity and uncompromising Temperature Stability. The Pro 800 uses convection and a Dipper Tube to deliver water to the group chamber in preparation for Lever Extraction. The Pro 800 Lever utilizes a vibratory pump simply to fill from the optional Water reservoir and operates with the conventional Lever design from the 1940’s. It’is the most reliable lever machine on the market as Tested by CaffeTech Canada. Price, quality and consistent brewing yields put the Pro 800 at Caffetech Canada’s Top choice for lever espresso machines in 2022.
- Solid Construction & Craftsmanship
- Well designed working
- Pour Over Or Plumb Option
- PID Temperature Controlled
- High Quality Steam & Water Valves
- Accessory Kit Includes Bottomless Portafilter
The Profitec Pro 800 Lever (Leva) Espresso Machine: Prosumer Perfection For Espresso
KEY FEATURES: PROFITEC PRO 800 LEVER ESPRESSO MACHINE
- Advanced PID: The PID controller in the Profitec 800 is hidden behind the drip tray. It allows you to adjust the boiler temperature.
- Professional gauge: The Profitec Pro 800 features a professional gauge that indicates pressure in the boiler. It is a great feedback tool which lets you better understand your machine and improve your final results.
- No Burn Steam & Hot Water Wands: The machine is equipped with no burn steam and hot water wands that can be manipulated without worrying about scolding your hands. Also, milk doesn't stick to a dual-walled steam wand as much as to a regular.
- Water Sensor: Level control cuts the power circuit if water is low, with a microprocessor that automatically controls the level of the water tank and boiler. A low water level warning will tell you when you need to refill. Please note: for proper operation, it is a must to use water with mineral content.
- Plumbed in or Pour over: The Pro 800 can be run as a pour-over machine using the included 3 liter water tank or it can be directly plumbed into your water main.
- Stainless Steel Housing: The Profitec Pro 800 is housed in a highly durable and very beautiful AISI 304 stainless steel case.