Home manual lever dual boiler

#1: Post by **walr00s** » March 3rd, 2021, 2:29 pm

Just casually browsing lever espresso machine options and noticing there doesn't seem to be a dual boiler option under 5k. Is there something about manual lever machine engineering that makes a dual boiler unnecessary or is this purely market driven?

#2: Post by **baldheadracing** » March 3rd, 2021, 3:04 pm

Both.

#3: Post by **drH** » March 3rd, 2021, 3:41 pm

I don't know if I'd conclude that it's unnecessary. Sure, most folks will point out that the big heavy groups are built to dissipate heat and bring the super hot water from the steam boiler down to the right temperature. Most do this reasonably well but everyone's palate is different and some people feel like certain spring lever models still overheat or are fussy with temperature. For example, there is a thread here about possible overheating on the Pro800, and while the Londinium is very stable, they sell a flow restrictor for their HX to cool the group for better results on dark roasts.

I think all of this is why Odyssey Espresso is making a PID espresso-first lever and why ACS is experimenting with a PID dual boiler, cartridge-heated single group lever.

I think experts and aficionados know how to make magic with their lever machines, but in my opinion a very home friendly, newbie-friendly and easily adjustable lever hasn't been cracked yet. Maybe the Bezzera Strega is closest with the super fast heat up.
I'd love to hear other points of view on this- I'm still running on a manual lever and haven't ever used a spring version.

#4: Post by **pizzaman383** » March 3rd, 2021, 8:36 pm

There are very few double boiler levers. Paul Pratt built a beautiful one. I built a serviceable one. Both were made with commercial spring lever groups. I recently converted mine to a manual lever.

Having a double boiler lets you separate the brew boiler temperature from the steam boiler temperature whether it is a lever group or pump-driven machine. Separately heating the group head adds additional controllability.

#5: Post by **drgary** » March 4th, 2021, 2:03 am

For my small, vintage commercial Conti Prestina lever, steaming is very powerful with a single 4.5l boiler, no matter what temperature I set on my self-installed PID. The Prestina has a dipper tube and is a spring lever. The Prestina's size is comparable to some home spring levers with commercial groups. I haven't tried to use the Prestina for many back-to-back shots and have heard that group temperature can climb, but we're talking about 18 lbs of metal that sinks heat, so this isn't comparable to a home lever, spring or otherwise, with a smaller group. I haven't owned a larger commercial lever and expect that its steam power is also a matter of boiler capacity. But then maybe when you get to home machines with a commercial spring group, you need enough boiler capacity to maintain stability. For a home spring lever like the Elektra Microcasa a Leva, the boiler is large enough that steaming is quite capable. When I had one, I didn't feel the need for more tuning of its steam capacity. When I tried a Ponte Vecchio Export, again the steam power was more than enough for home needs.

Another small commercial lever that should be temperature stable with powerful steaming is the Lapera DS, where production is only beginning. It's a reproduction and modernization of the Brugnetti Aurora with a single group, cartridge heating and a PID.

Lapera DS lever first look.