Our Thoughts on Spring Lever Machine 2014 Feburary

IMG_4294Matthias Suchert and I have been using a two group spring lever machine made by Bosco Espresso from Naples since we started out in Sep 2011, with the idea of starting from basic in both machinery and bean’s choice in serving two single origin beans as espresso at any time for espresso base drinks.  We read as much as we could on line and has been tasting coffee from modern pump machine and spring lever machine (Prufrock at Leatherlane vs at Present) and pulled shots in tasting beans we know at Londinium Espresso before we made the choice base on the cup to embark on this journey.

With our limited knowledge and experience,  the more we look into the history and construction of vintage spring lever machines and some amazing machine restoration engineers had done and designed, the more we realize how little we know.

Our experience is limited to using machines we can get our hands on and pulling shots from beans that are not too dark in showcasing the origins or particular terrior/ process. So if you have other thoughts and ideas please help us expand our ways in approaching the creation of better coffee. The following are some of the questions we had during the process of choosing machine and also from speaking to customers and visiting baristas to our bar:

Why do we choose spring lever machine over modern machines?

We thought, if we start, we should start from the ground up: Use single origin beans and a machine that could make decent shots of them. If it needs going back to the engineering of the beginning of modern espresso (with crema) then let it.


Moreover, both of us are, on one hand are rather visual based, there is nothing better if the process is reflected in the working of the machine, on the other we are rather hands-on, we love the physical aspect of literally pulling the lever and get to control the shot during the process of extraction to just pressing a button or a paddle that relays to electronic controls (we frankly have limited budget as well)

What’s the difference of a Spring Lever Machine to most other espresso machine we see in coffee shops?

Spring Lever Machine uses spring to achieve the required pressure while modern machine uses pumps.

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As a result, operation wise, it lacks any push buttons or paddles to produce shots because there is no pump to turn on. One has to pull a lever with force (approx 10kg, in some case more depending on spring) to load a spring to start the process of genuinely pulling espresso.

Spring Lever Machine’s engineering predates any pump driven machines dating back to development from Gaggia’s invention of piston driven espresso machine in 1938.  Instead of a pump, pressure is applied by spring/(s) pushing water down through the coffee bed.

When a barista pulls a shot, this literally means they pull down the lever; it loads a spring by elevating a piston into the cocking position. This allows water to enter the brew chamber to pre-infuse the ground at either boiler or line pressure. When it is released, which is manually controlled, the tensioned spring then pushes the piston down, forcing water through the coffee bed at high pressure which then decreases gradually to zero pressure.

How does the different mean in producing pressure in Spring lever machine differ to modern pump machine reflect in the cup?

Our experience in using modern pump machine is limited, but we can probably look at the steps in pulling a shot and its properties to speculate on the difference:

First, on pulling down the lever and into cocking position, it is the pre-infusion stage: water enters the brew chamber through 4 holes and pressure is at boiler pressure/line pressure, which the barista has full control on length of time. Some machine has an adjustable restrictor in controlling flow rater of water as well. This is different to most pump machine, pre-infusion is preset. (except in Synesso, Strada, Slayer). It is believed pre-infusion enables one to reduce chances of channeling so it is much favored.

Second, on releasing the piston, the pressure reaches as high a static pressure of 12bar or higher in some machine. This forces an even column of water through the coffee bed, where as in a pump machine, water exit from a couple of small holes at the dispersion plate. This even yet gentle column of water enables you to have any headroom in the coffee pluck without affecting extraction, which is something pump machine cannot do.

Third, as the piston is pushing down, the pressure naturally decrease to zero very smoothly due to physicality of the spring. The barista can at any time increase or reduce the pressure by manipulating the lever, which is exactly what some of the most advance machines are trying to imitate electronically through the pump. These machines generally double the cost and one has to deal with electronic components, while most of the other pump machine has either line in preinfusion or full pressure to 9bar only.

Forth, the temperature of water in the group drops very slightly in relation to time where as in pump machine they are often fairly stable. We didn’t find any dramatic issues with this but somehow it has less chance of a bitter cup.

All these attributes of spring lever machine results in a slight different cup to most pump machine: often fuller body more velvety mouth feel and easier drinking cup with single or blends. Somehow with our little experience it wasn’t that difficult to repeat decent cups, which never surprise us.

Despise all these controls and properties, from talking to a lot of barista before we start and also when barista first visited us, it seems in general they don’t like spring lever machine at all and think they are very difficult to use, fluctuates in temperature and don’t produce a clean cup.

I guess most baristas learn to operate an espresso machine by pressing a button to turn on and off, or a paddle. Some works with volumetric control so anything different makes them skeptical, adding on top a max resistant of 10kg pull it may not be so desirable if they have to pull hundreds of shots a day.  Moreover, in the old days, there isn’t automatic refill of water, so the barista has to watch water level, look at the shots (on how it pulls), work on milk, it may just be too much, not to mention if it is gas control.

Furthermore, from previous experience of tasting coffee from spring lever machines, they normally don’t serve very tasty drinks due to location or cultural difference. It was only until Gwilym and Matthias started Prufrock at Presents I was surprised at the difference.


On the issue of temperature fluctuation and control, there are several design on how spring lever machine are engineered which gives different degree of consistency and ease of control. We had to learn the behavior of our machine(a hybrid dipper) when it is on idle and in use (busy or quiet period) but after that, there seems to be a repeatable pattern that is not too difficult to manage. In a very odd way, we speculate whether the machine is designed to have ‘uniform’ temperature or just a range, so that on brewing, it drops, extracting less towards to end to reduce bitterness.

It is worth looking into how typically spring lever machine are designed to understand the character in temperature control. We looked into several design but they have similar group head design: it is very heavy brass, internally there is a colar, enables a space between the outer wall and inside allowing water to either circulate or sit in.

First, most Spring lever machine are typically dipper system: a very heavy brass group head directly mounted onto the boiler conducting heat to keep exposed group warm. Internally there is a tubing connecting the group to the bottom of the boiler (cooler temperature). So brew water and steam uses the same boiler. Although this keeps the group at higher temperature for group to be ready to use, but after succession of  shots the group might overheat even it is engineered to be a heatsink with heavy brass. So barista typically switch between groups or use a cold towel.

Second type is a hybrid dipper: the group is mounted onto the structural carcass, the large tubing that connects boiler to group has a secondary chamber for brew water before entering group. Although the group is cooler on standby and needs warming up after idle for over 5min, yet the temperature of brew water is very consistent on consequence of shots (93.2-5c, using SCACE2), unless the pressure stat is set very high.


Third type has group mounted onto structural carcass but water is feed by an open loop thermo syphon: the group has an inlet and outlet. A circuit of water is moving continuously into and out of the group from the boiler directly to keep it up to a constant temperature. Hot water will escape into the brew chamber only when lever is pulled. This system keeps the groups up to a fairly good standby temp without overheating and provides a reasonably stable shot temperature.


Forth type has groups mounted directly onto boiler to conduct heat and water is heated by heat exchange before entering group. Using heat exchange method to heat brew water separating from the steam boiler is a way to give an extra control of temperature stability (one can control flow inside to optimize temperature)

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The fifth type that we know of is with groups mounted off the boiler, heated by thermosyphon from a heat exchange. . This machine is equipped with the optional adjustable needle-type restrictors, so one can adjust temperature separately per group. Also the optional switch activated automatic temperature purge system is installed. No need to flush the group to get to the optimal temperature after being idle for a while. In theory this provides the best control of standby temperature and also shot temperature as both can be controlled without much effort. (photo from Kees van der Westen)


All these are engineered base on thermodynamic theory using some heavy duty material, like the group head weights over 5kg to act as heat sink rather than delicate electronic controls. So it lacks the modern numerical display nor PID temperature selection down to one tenth of a degree which one might like to adjust for different roast level or origins. Using spring lever has to rely on manipulating preinfusion time to micro manage temperature.

Is there anything else that makes Spring Lever Machine stands apart to modern pump machines?

The theatrical visual aspect of pulling a shot that is actually coherent to the design of the machine: From pulling down the lever, lifting it then seeing levers rising up as the shot brew, I don’t know how pressing a button or pushing paddles can replace that. It is particular dramatic when there is multiple groups with levers moving up and down.

The physical tactility on the pulling the lever somehow makes one connects a little more to the working of the machine. I guess from the customer point of view, it is also a performance aspect of the barista.070

Furthermore, if a barista wants the customer to focus on the senses particularly visual and taste, the sound of pump humming in the background may not be so desirable. The silent spring is really a bless.

Coming back to cleaning, because there is no back flow of water, the shower screen and brass block of the piston is much cleaner, cuts hours of the after hours cleaning daily.

Of course, there are issues one needs to be careful. The levers can break jaws if there is no resistance in the portafilter and contrary if too much coffee clogging basket, one cannot just unlock the portafilter, otherwise the pressure of hot water could make some damage.

Would you recommend coffee shop owners to consider spring levers?

If one looks for simple elegant solution in offering quality drinks then definitely, it makes espresso an enjoyable experience, not to mention it is an amazing conversational point. However, if it is about numbers then maybe not, particularly it will put a lot of not so keen barista off with reasons mentioned.

You can see spring lever use in some world renowned coffee shops, such as Blue Bottle Coffee, for their single origin. Prufrock at Present always wins preference than their Leatherlane shop!

On the development of modern machines goes, we respect very much the effort being put into perfecting the condition in pulling espresso such as utilizing the pump to reduce physical constrain, precision PID temp control for consistency in both quiet and busy hours; refine temperature control down to 0.1c  for different roast levels and origin of beans; programmable volumetric/ weight controls, pressure profiling, etc are very obvious. While some of these spring lever machine lacks but quite a few of the sort after characters and quality were inspired by Spring Lever Machine.

I guess it is like what the head engineer at Simoneli has said, spring lever is like driving a Ducatti, where as the modern machines are Honda. One cannot replace another but it is good to have the opportunity to clarify any misunderstanding. A roaster friend was really dubious on spring lever machine, after he had a cup from us and pull quite a few shots, he got his roastery one and simply enjoyed the process and more importantly, the cup.

How about for home barista?

If one consider buying an espresso machine as a long term investment and also include the long term cost of beans use in dialing in on pump machines, spring lever machines often come as a revelation from lots of users. Look up voices in forums as evidence, but make sure you get a proper one with commercial group head.

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Water again

We have been continuously interested in how water changes the taste in coffee we brew.
After seeing the performance and reading paper of UKBC Maxwell’s and his chemistry collaborator Chris Hendon we wish to understanding more as we have experienced TDS reading of water is only the tip of an iceberg.
Now we have an elaborate report and also a link in how we can do similar test to add to the discovery and debate by Jeremy Hartley


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HOI CHI NG  has written an article on the Spring Lever Machines – go and check the Caffeine Magazine February and March issue when it comes out and tell us what you think.

Way to go, keep pulling these shots, Hoi Chi!


Merry Christmas 2013

Following much debates on grind size distribution and testing lots of grinders for Espresso earlier on
,we conclude fine grinds can be brilliant at times!
Have a great festive seasons!!
Matthias + Hoi Chi


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Six grinders one coffee with a spring lever espresso machine and heavenly donuts

One coffee:
Workshop Coffee Co
Cult of Done Espresso
La Ilusion Santa Ana Region, El Salvador;
Fully washed process;
95%Bourbon, 5% Pacamara
Roasted on 2013 July 30th

Six Grinders:
1: Mazzer Robur E, 71mm conical, 420rpm
2: Eureka Olympus KR, 68mm conical, 330rpm
3: Compak K10, 68mm conical, 420rpm
4: Eureka Olympus 75, 75mm flat, 920rpm
5: Anfirm Super Caimano, 75mm flat, 800rpm
6: mahlkonig EK43T, 98mm flat, 1480rpm

Spring Lever machine:
Bosco Espresso 2 groups,
pressurestat set at 1.1bar; hybrid direct dipper (groups not direct mount to boiler); spring pressure: static 11bar, dynamic on SCACE2: max 6.55bar then drops; brew water temp in SCACE2: max 93.2c then drops 3c during extraction

Brew Recipe: 18g dry on VST basket, then as close as possible to 10s preinfusion, add 25s on first drop, +-30g brew.
We don’t have a refractometer to measure extraction %, so if anyone like to know and has the instrument we are happy for them to come and measure.
Another note is that we try to dial in to get the flavour as close to the dry grind fragrance as possible.

Tamping: we nutate and tamp flat the grind so it is as similar as possible for all the 6 grinders.

Scale: 0.1g increment

Water: Everpure Claris filter set at 2

It is with naked portafilter, so we can observe buttom of basket to see how coffee exit the basket and the changes through out the brew.

On the EK43T, we have no experience like Jeremy had and his updates was not published yet when we were testing,  so we did not have any sieves, VST refractometer, etc. http://www.prufrockcoffee.com/2013/08/the-kaminsky-report/
What we did was weight beans, drop into grinder, cup to collect and had knocked the chute, drop grind into portafilter with paper cup funnel, shake to break clumps and make it as uniform as possible, then tamp.

We had about 6-7 rounds of test for those who thankfully came but lost count of dialling in and repeated test in between.

But I have to say, although the intention is to have as close a dry weight, tamp method/ weight, group temperature, shot time and brew weight as possible, due to my ‘skill’ there is unfortunately a fair amount of inconsistency particularly in serving them to taste. So I am more than grateful for those who came and took part!

At the end of the day, I did the whole set again, 2 cups per grinder to understand inconsistencies and have the following thoughts, with reference and  feed backs I had from those who came:

1. Robur: a powerful punch of flavours; baker chocolate/almond bitterness then red stone fruit acidity/ sweetness with lingering baker choc/ almond
The layers/ sequence are packed really tight. Most taster said they didn’t like the cup: “bitter, sour ….”. Some comment the lever machine temperature is inconsistence ( not according to SCAE2 test), but somehow corresponded to taste description above, too punchy/ intense and tight.

2. Eureka Olympus KR: softer delicate experience: clean red stone fruit acidity follows by sudden spike of fresh lemonade acidity/ stone fruit sweetness / very tiny almost undetectable hint of baker choc/among bitter-sweet. Layers/ sequence of flavours are clear and distinct yet joints up one after another softly distinctively with clarity. General taster comment was this was rather acidic, not the unpleasant one. After being at Ben Kaminsky workshop, I wonder whether this sudden peak of acidity is ‘sour’ note by underextract of larger grinds or not…

Perhaps the smaller burr with different geometry in the burr’s cutting design and low rpm made it tasting rather unique among the espresso grinders.
This is a DIY doser less with timer, I am suspecting if we has the doser chamber it might even made extraction ‘better’?

3. Compak K10 on demand: distinctive but not overwhelming (unlike Robur) strength. Soft Red stone fruit acidity / sweet red stone fruit dominant than acidity, intertwine with hint of baker chocolate/almond bittersweet. It felt rounded big sweet juicy that is balance easy to drink cup without delicate details, similar to 5. Anfirm. Most taster like the taste from this grinder.

It will be nteresting to investigate further the burr geometry difference vs Eureka KR (same size) Yet with the speed it has (same as Robur in rpm but different size is slightly slower) it is perfect for busy coffee shop yet more pleasant in taste.

4. Eureka Olympus 75: weighted intensity, red stone fruit acidity then a short peak of preserved lemon (in salt) with clear presence of baker choc/almond bittersweetness/ red stone fruit sweetness. Aroma has hint of vanilla/ mash mellow. Intensity and tasting notes made this drink just slightly less aggressive than Robur E but not as easy drinking as other.
(Will clean out grinder to re-evaluate) Most taster dislike the cup with similar tasting note as the Robur E.

The new on demand feature is very simple to set and quick access to manual over ride. Dosing is neat and clean with LED lights at perfect location. Yet, we ran out of time to check dose acquiesce and repeat ability ( we did manual on all machine)

5. Anfirm 75mm flat burr: it is well rounded Red stone fruit acidity/sweetness and a hint of the baker chocolate/ almond bittersweet at the end. Sweetness is more dominant than acidity here. It is similar to the K10. Most taster also like the taste from this machine as well, the sweetness seems the best seller.

We have not yet check the geometry of burr vs Eureka’s 75mm but suspecting the taste difference could be the rpm is lower and doser chamber helps to ‘even out ‘ grinds. ( update on burrs: the Eureka has a slight (1-2mm) wider burr cut area to the Anfirm)

6. Mahlkonig EK43T: soft uniform taste of mild baker chocolate/ almond bitterness, second soft of all behind Eureka KR/bright light red stone fruit acidity/ red stone fruit sweetness. They are all softly evenly layered without one dominating others similar to the KR. Most taster like the cup, saying it is more variety of flavors in there yet not overpowering/ unpleasant.

Evenness of how coffee exit filter basket depends a lot on whether the grinds are shaken/ tossed inside the funnelling cup before tamping, hopefully I will get better insights in the technique after Tuesday’s workshop.

It was extremely satisfying that one can weight 18.2g and get 18.1/2g out so quick (grind time 3-4sec) in dialling in espresso easily. It is similar with Versalab M3 or the new HG One hand grind in the process, with little to no retention. (Not comparing grind quality/time, just retention amount)
Perhaps shortening the legs/ lowering into the bar helps visually, and perhaps using a hopper with dosing device like the Versalab could work in shop environment ( then post sieving/ weighting again) where as now is perfect when one has small amount of sample to taste.

We did not have the chance yet to measure grind temperature, it felt like a +5c increase but will do more later in the week.

We were aware of the difference of the two conical grinders at the bar in Exhibit Golden Lane but never had a chance to taste side by side with the ones we have today. So even though it was not that scientific, with doubtful level of consistency, it was still insightful to be able to do it and get an impression of it all.

It is the beginning in trying to understand something very complex, I hope this hands in study can continue ! ( need helps to get more grinders, measuring device for grind size, sieves, microscope to see grind shapes, accurate scales (0.01 accuracy?), thermometer, humidity checks, pump base espresso machines, different roast style of coffee, more tasters….. Anyone? )

Of course, hopefully we will have another chance to do more insightful espresso tasting in addition to Coffeeshots after Ben Kaminsky class on Tuesday night.

Thank you to those that came and super support from the team at Dunnfrankowski and super tasty donuts from Chloe!

Note: cups of coffee are in order of the grinders….











Loustic, a wonderful addition to Paris growing coffee shop

When you are at it near Pompidou and would like some delicious coffee, do make a little effort and walk north to 40 Rue Chapon.
You will find a beautiful red Cafe sign with bulbs.
Loustic serves coffee roasted by Caffenation from Antwerp, as espresso and brew.
We will let photo speak and let you taste the delicious coffee!








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Beyond delicious coffee: Telescope Cafe, where style is

When you are able to taste good coffee everytime you visit a coffee shop it is simply a delight.
This is Telescope Cafe in Paris.
Not only that but somehow they attract as stylist customers
Thank you Telescope for bringing them.








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Coming Soon Coffee at Wallpaper* Handmade at Leclettico

In just about a weeks time we will be in Milan setting up a ‘bar-raising (and pulse-raising) coffee stop for Wallpaper magazine Handmade at Leclettico.

If you are around for the Milan Furniture Week, please come around for a coffee from April 9-13th.

We are super excited to be invited by Wallpaper Magazine to bring a customised espresso machine, set up a brew bar and of course run it during the fair. Imagine how difficult it was to keep it quiet until now.

For espresso, we will be serving, as we always have, a choice of two single origin beans.
We have grinder sponsor from our favourite Eureka and the new Brewtal Grinder by Alex Maclntyre.
Coffee will be pulled from our beloved 2 group Bosco spring lever machine from Naples.

For the brew bar, we have two different filtered water of different TDS levels to see how the public would taste the difference with one SO bean.
It was an idea that came about when we did coffee cupping with Chloe using water of different TDS levels, that there is no one best TDS, as they bring out different quality of beans from different origin, so why can’t coffee bar has bespoke water for different beans?
Chloe of Bespoke Water System is making it possible with supplying us 2 set of Reverse Osmosis system and Marco for kind understanding and generous support with 2 Uber boilers and an Uber grinder.

We really wish we can afford to keep all the equipment for anyone interested to work in and experiment with us than just for 5 days….

With beans you might like to come and taste the amazing line up of roasters:
Hasbean Coffee Roaster (UK)
Coffee Collective (Denmark)
Tim Wendelboe (Norway)
Fresh (Hong Kong)
Knockbox Coffee Company (HK)

Apart from coffee we have to design the bar as well, focusing in the hope of creating a different kind of coffee experience.
We use Kebony timber for its dark heavier but calm and tactile quality as the base for all the actions and Architectural Titanium fins cut with soft shapes to form an ephemeral form in disguising the heavy form of bar.
The geometry is the bar has a bend to make clear distinction of brew and espresso. It also helps to enable one to see behind the machine in action of pulling shots.

On the customisation of our machine, will will have our transparent case so the instrument for the cup is naked to the eye and there is also new cut out drip tray and cup warmer by architectural titanium with an unique pattern.

Lastly, we have Kwin Studio making a one off sugar bowl spoon holder set for us.

For now we just needs to be there, hope a shipments arrives, set up the bar with power and water and able to make tasty coffee!

Come and see us! We will update our progress.




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Coffee Cupping with water of different TDS value

John Gordon and James Bailey has been experimenting and exploring in details how water affect the taste of coffee. With Chloe on Sunday we started by looking into how most of us might get water from: main and Brita filters and see how it tasted comparing to water from two different RO system with different Total Dissolve Solids( TDS) value and composition of water.
So they are as follows:
1. Main Water from London Lower Sydnham, TDS 325
2. Brita Filter TDS 245
3. RO TDS 80
4. RO TDS 120
5. RO TDS 150

We picked three different coffee roasted by Hasbean Coffee Roasters to see how various water affect the taste:

1. El Salvador Miravelle Washed COE2012
2. Ethiopia Kebel Konga Washed
3. Sumatra Raja Betak Honey Process

On the table we divided the cupping bowls into 4 groups: 3 coffee origins and 1 pure boiled water as control. They were all randomly labelled and orders were mixed within the group so no fix pattern of sequence can be matched.

We then simply cupped all the coffee based on similar routine to the SCAA cupping protocols and encourage al participants to write down tasting notes, of what they like or not and what it is that make that decision.

It is thought provoking that 6 of us identified clearly and agreed on which we dislike most: mains water and Brita water, even Brita actually is very soft (see photo).
When it comes to what we like most, it seems it is more personal and also changes according to the origin of the coffee beans. For example, the Sumatra only taste bitter and roasty with high TDS water and changes to sweet fruit and layered with lower TDS. Furthermore, the same TDS water works for Sumatra would make another coffee (El Salvador here) be a bit too bright even all the tasting notes are there, just too punchy !

What we would like to know next is how water composition affect taste as TDS value is only a generalisation value. It will be interesting to know how other content in water, chlorides, magnesium, bicarbonate, nitrates, potassium, sulphate, sodium, calcium and silica might affect taste and mouth feel of brew.

Chloe is likely to provide you with more information on her blog soon
http://www.faerietalefoodie.com/but this is a little preview and some thoughts after attending James’ workshop and this test.

Thank you to Chloe in organising it and her colleague that joined with Kate and Mike.

For us, we will definitely have a system (one day) where we have different water for different origin/ character of beans!

Please note, the last two pictures are taken at classes conducted by James and Gwilym last year.









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Not here but here

As most of you might have know already, we are no longer at Exhibit Goldenlane Estate but it does not mean we are gone completely.

Please check the blog for our activities in coffee and things we like.

Furthermore, we will soon has some very exciting news for you all, something rather unexpected coming soon ….