La San Marco single group lever

Posted on January 7th, 2016

converted La San Marco single group lever

Dual boiler, dual PID commercial lever beast!

This beast started out life as a La San Marco 85 series, single group volumetric heat exchanger. I bought it last year as a fixer upper, the boiler was over filling and it needed a general going over. 9 months or so later and it’s a very different machine to the one that came in!

Turns out the over filling problem was a fractured heat exchanger, so that ruled out keeping the machine conventional – the heat exchanger would have to be decommissioned, capped off and become part of the steam boiler volume – I didn’t like the chances of a successful repair.

At that point it became a total strip down, and while I had the bare chassis on the bench, I started playing around with the possibility of fitting a lever group that I had spare. With an extra cross member in the chassis, it would totally work! So, off to see my mate Gonz who worked his magic and welded in a cross piece to take half the group flange. The group was already fitted with cartridge heaters, from back in the days of the Quick Mill Achille testing with Talk Coffee, so why not take advantage of that? Then, why not add some extra precision with a dedicated brew boiler as well? Yep, it would fit with a bit of wrangling. I also adapted a small volume heat exchanger into the existing steam boiler to provide pre-heated water to the brew boiler. Serious overkill at this point but why the heck not?!

So, this ended up being the most advanced lever machine I’ve built to date, with a PID controlling the group and a PID controlling a dedicated brew boiler just behind it, temperature control is phenomenal. By tweaking the two set points, you can even control the shape of the traditional lever temperature profile.

The original boiler is slightly under-specced at 1700W, but it allows the total machine wattage to stay at approx. 10 amp draw, with 600W in the brew boiler and 200 in the group. It takes a while to reach 1.5 bar, the group is hot well before then – but is ready to go after 25 min approx. and steam pressure is never an issue due to the huge volume for a single group, and added insulation.

It’s plumbed in only, as the line pressure primes the brewing circuit and is used for pre-infusion. The spring installed in the group (new of course) generates 10 bar peak pressure. It’s a delight to use and pulls wonderful shots. I’m mad to sell it, but that’s the reality of running a business, I can’t hang on to everything!

Summary of work done:

solved issue with heat exchanger crack
entirely new brewing system – group, boiler, pre-heater, PID control X2.
new autofill controller, SSRs, wiring as required.
rebuilt all existing valves, plumbing.
powdercoat exterior panels in electric blue hammertone (bold, I know, but it looks stunning!)

It’s probably the most advanced lever machine in the world, in terms of temperature control (at the time of writing – 2016). Offers will be considered. I am in the process of finalising fitment of the front panel, as it was never intended to cover a lever group. Once that’s done she’s ready to go, will not take me long!

Andy’s Londinium

Posted on August 9th, 2013

Andy’s Londinium

Domestic lever dual boiler conversion

The Londinium Espresso L1 is a new addition to the market for single group lever machines intended for domestic use. There has been a recent resurgence of interest in lever espresso machines, as we are finding out more about the subject of ‘pressure profiling’, or controlling the water pressure applied to the coffee puck at different stages of the extraction.

Andy was a little disappointed with both the fit and finish and the temperature stability of the machine, so we decided to see what we could do to take it to the next level. Without going into too much detail, the Londinium uses a fairly uncommon thermosyphon arrangement to get enough heat into the massive group. After gathering some data on how the thermosyphon functions and comparing this with other user’s data from around the world, it appears that there are conditions that can alter it’s performance, resulting in low group temperatures and sour shots.

We considered a few options, one of which was reconfiguring the thermosyphon into a true heat exchanger that operated from mains water pressure instead of the built-in tank, but Andy was keen to retain the ability to run from tank. This meant a drastic alteration of how the group was heated, and the fabrication of a separate brewing boiler to tightly control the water temperature at the group. Luckily, the internal construction meant that the original boiler could be retained and minimal alterations to the layout were required.

The end result is a traditional lever machine that has all the inherent temperature controls of a modern dual boiler machine. Changing the set temperature of the brew boiler controller results in a quick change in the idle temperature of the group itself, which governs the temperature profile of the shot.

We were also able to address a few of the annoyances with machine fit and finish, such as ease of emptying the drip tray, placement of switches and internal venting of the anti-vacuum valve.

Andy is stoked, and the proud owner of what may be the most technically advanced lever machine in the world.

Microcimbali restoration

Posted on September 21st, 2012

Microcimbali restoration

Vintage domestic lever machine

This was a good example of the sort of horrible condition that many vintage domestic machines imported from Italy are in. Plentiful rust, corrosion, scale, damaged chrome, perished insulation, seals, etc etc. Beware the optimistic eBay description! However, the appeal of these vintage lever machines is justified – once restored, they really are functioning design icons of a bygone era.

Luckily, the most important parts of the machine were fixable. The worst case scenario is that the element filament or insulation is damaged, meaning a costly one-off custom element has to be made. Luckily this was not the case and repairing the element just involved re-sealing the terminals with high-temperature insulation compound.

Further work included:

Repairing hole in cast aluminium boiler by drilling out and plugging internally with new material
Drilling out and re-threading damaged mounting points on boiler casting
Re-wiring with modern silicone insulated cable
Replacing all perished seals with OEM or custom made versions
Polishing exterior surfaces and fittings

These old lever machines fascinate me, and I love working on them. They are always a challenge, but there’s nothing more satisfying than getting a perfect shot out of a machine you’ve restored, and it’s now an asset the new owner will enjoy for many years to come.

Nic’s Bo-Ema

Posted on September 21st, 2012

Nic’s Bo-Ema

Vintage two-group lever machine

This beautiful lever dates from 1964, and represents both Australia’s manufacturing and cultural history as it was in Sydney in the 60’s. Espresso bars were gaining popularity, and at that stage the only commercial machines available had to be individually imported from Italy, or brought over as cargo by emigrating families. The story goes that two enterprising continental chaps named Bordignon and Emer got together in their Revesby factory, which at that time churned out terrazzo polishing machines, and decided to have a go at producing a machine locally. The result found it’s way into a few choice locations, and Bo-Ema still produce espresso machines in Sydney, though the company has changed hands a few times, and modern bo-ema’s are not exactly a thing of beauty.

The current owner wanted to give it a thorough restoration to working condition while preserving the patina of a lifetime of hard work.

With most restorations, the machine is completely stripped down to it’s component parts, everything is meticulously cleaned, polished and reassembled with new parts where necessary, then tested and tested some more. In some cases there are hundreds of hours of labour involved, particularly if parts that are no longer available have to be made – in this case the seals for all the valves had to be custom wound from a mixture of oldschool hemp fibre and modern PTFE.

Other major jobs included:

Custom made powdercoated chassis brace including new feet to replace the missing originals
Drilling out rusted steel studs from boiler flange and replacing with stainless/brass hardware
Replacing rusted group springs to achieve full 10 bar pressure
Complete re-wire with modern pressurestat and thermal cutout for safety and reliability
Hand polishing valve bodies, lever handles, fittings

The result was a machine that is working better than when it left the factory 50 years ago – there’s nothing quite like a commercial lever machine and Nic is lucky enough to have one that is a significant part of Australian espresso history.