Spring Levers for Light-Roast Coffee Fans - Page 2

A haven dedicated to manual espresso machine aficionados.
shotwell

#11: Post by shotwell »

This is not my experience, but I'll admit to only using the max, a p100, my Kinu, and a Q2 hand grinder (similar to a commandante) with the dipper. I don't see that changing with virtually any competent grinder but I'm also open to being wrong here.

RyanP

#12: Post by RyanP » replying to shotwell »

When I was using a Mahlgut conical grinder I found that using the default (at the time) 3 bar PI with the LR made a significant impact on the end result with light roast SOs. That was less the case with the monolith flat. With the flat max I have the PI set to 1.5 bar and never bother to change it. Just my experience.

Cerini Coffee & Gifts: official US importer for Olympia Express
Sponsored by Cerini Coffee & Gifts
shotwell

#13: Post by shotwell »

It's a bit tough to tease these things out on the lr because, as I understand from reiss, the pi pressure controls the shot temp in that setup. That's a significant confounding factor that you'd just dial by changing temp in a different machine.

baldheadracing
Supporter ♡

#14: Post by baldheadracing »

I am reminded of a quote:
"... You can't make a race horse of a pig."
"No," said Samuel, "but you can make a very fast pig."
-John Steinbeck, East of Eden

Used as-is, spring lever machines typically:
- start with an upwards draw of air through the puck;
- followed by a variable time of pre-infusion at very high temperature, very high flow, low pressure, and variable volume; and then a
- quick rise to peak pressure, followed by a linearly-declining pressure; combined with a
- linearly-declining puck temperature during the pull.

I see three classes of spring lever machines for light roasts:
First: Machines with spring lever groups that were designed for a low-grown Brazil-dominated coffee landscape where everything was roasted to at least to the beginning of second crack;
Second: Machine(s) that by happenstance are great at light roasts; and
Third: A "pump machine with a lever group bolted on" (Reiss Gunson quote).

The first class of machines can only get hot enough for light roasts by increasing boiler pressure. This upsets the thermal equilibrium of such machines. Thermal equilibrium meaning walk-up-and-pull anytime and keep pulling shot after shot (given a reasonable minimum rebound time) and always getting the same brew temperature profile. Most(all?) vintage one-group machines designed for commercial use are like this. You can make these machines hotter and they'll work, but I think that they might not make a light roast shine as much as the next two classes of machines.

The second class of machines has groups that over-heat - the brew temperature climbs after consecutive pulls/longer warm-up times. Coincidentally, this leads to not having a declining temperature profile during a pull. These are usually small groups - the Elektra Micro Casa a Leva is the most well-known example, enabling tea-like long brew ratios with amazing clarity and separation of flavours when pulling nose-bleed-light roasts. However, allonges are not happening at 17g doses, or even half that - my typical long pull is 6.5g-7g in, 30-ish second pre-infusion, to get around a 1:6 brew ratio.

The third class are fast pigs - Strega, Londiniums with pumps, LM Leva X, ACS Leva's(?). A pump lets the group be pre-infused at various pressures and/or be filled with more water during pre-infusion. While directly controlling available water volume, this also controls extraction pressure profile (due to differing compression of the spring at different engagement/catch-points) and also the temperature profile behaviour during the shot. As these machines have significant technological differences, exact behaviour will vary. (As an aside, I think that a Strega pulling these kinds of roasts strongly benefits from a pre-infusion pressure gauge. Also, an additional switch on the pump is convenient. A PID on the grouphead heaters is probably also a good idea, but I use flushes instead to (only) lower brew temperatures.)
Jeff wrote: I'm not interested in fancy double-pull rituals to get the ratio. Prep, lock, infuse, let the spring work its magic, enjoy...
Finally, I'm not sure if you would classify this as a "fancy ... ritual," but in all three types, manual retardation of the spring can be used to lower extraction pressure, as adeptly demonstrated in another_jim's famous video review of the Strega where he pulls a light-roast Geisha (http://www.youtube.com/watch?v=T9OUNXVLY_o , go to 3:50-7:55). This takes some practice to do, and, at least in my experience, is nowhere near as easy as it appears in the video :-).

Just my opinion; I'm sure others will disagree. FWIW, my guess is that the Leva X would be the best spring lever machine for light roasts.
★ Helpful

LObin

#15: Post by LObin »

baldheadracing wrote:I am reminded of a quote:

-John Steinbeck, East of Eden

Used as-is, spring lever machines typically:
- start with an upwards draw of air through the puck;
- followed by a variable time of pre-infusion at very high temperature, very high flow, low pressure, and variable volume; and then a
- quick rise to peak pressure, followed by a linearly-declining pressure; combined with a
- linearly-declining puck temperature during the pull.

I see three classes of spring lever machines for light roasts:
First: Machines with spring lever groups that were designed for a low-grown Brazil-dominated coffee landscape where everything was roasted to at least to the beginning of second crack;
Second: Machine(s) that by happenstance are great at light roasts; and
Third: A "pump machine with a lever group bolted on" (Reiss Gunson quote).

The first class of machines can only get hot enough for light roasts by increasing boiler pressure. This upsets the thermal equilibrium of such machines. Thermal equilibrium meaning walk-up-and-pull anytime and keep pulling shot after shot (given a reasonable minimum rebound time) and always getting the same brew temperature profile. Most(all?) vintage one-group machines designed for commercial use are like this. You can make these machines hotter and they'll work, but I think that they might not make a light roast shine as much as the next two classes of machines.

The second class of machines has groups that over-heat - the brew temperature climbs after consecutive pulls/longer warm-up times. Coincidentally, this leads to not having a declining temperature profile during a pull. These are usually small groups - the Elektra Micro Casa a Leva is the most well-known example, enabling tea-like long brew ratios with amazing clarity and separation of flavours when pulling nose-bleed-light roasts. However, allonges are not happening at 17g doses, or even half that - my typical long pull is 6.5g-7g in, 30-ish second pre-infusion, to get around a 1:6 brew ratio.

The third class are fast pigs - Strega, Londiniums with pumps, LM Leva X, ACS Leva's(?). A pump lets the group be pre-infused at various pressures and/or be filled with more water during pre-infusion. While directly controlling available water volume, this also controls extraction pressure profile (due to differing compression of the spring at different engagement/catch-points) and also the temperature profile behaviour during the shot. As these machines have significant technological differences, exact behaviour will vary. (As an aside, I think that a Strega pulling these kinds of roasts strongly benefits from a pre-infusion pressure gauge. Also, an additional switch on the pump is convenient. A PID on the grouphead heaters is probably also a good idea, but I use flushes instead to (only) lower brew temperatures.)

Finally, I'm not sure if you would classify this as a "fancy ... ritual," but in all three types, manual retardation of the spring can be used to lower extraction pressure, as adeptly demonstrated in another_jim's famous video review of the Strega where he pulls a light-roast Geisha (video , go to 3:50-7:55). This takes some practice to do, and, at least in my experience, is nowhere near as easy as it appears in the video :-).

Just my opinion; I'm sure others will disagree. FWIW, my guess is that the Leva X would be the best spring lever machine for light roasts.
Great contribution! Very well written!

I have a question about the 2nd category in which you classify the Mcal. You wrote that the levers in this category don't have the same declining temperature as other levers in the 1st and 3rd categories. Isn't the drop of temperature happening instead during preinfusion since the group is unable to maintain the sudden rise of temperature from the water entering inside the group?

From my experience, smaller groups like the LPE (assuming it would fall in this category) have quite a pronounced temperature curve during a pull. However, the most drastic change happens when raising the lever as I typically observe a +13, +14c at first. During preinfusion though, the group quickly looses temperature, sometimes up to 6-7c depending on PI duration. During the pull, the group raises again by a few degrees and is quite stable from there.

On my L1, the group only raises by a couple of degrees when the water enters the group. It's pretty stable from there, with a very minimal drop in temp.

Of course, these observations are related to group temperature, not extraction temp, and based on my own prob locations. They don't translate, in extraction temperature the same way for the LPE and the bigger Londinium group since there's a huge difference in heft as well as water temperature before it enters the group.

* My 78 Europiccola is moded to behave like a millenium group.

I know I'm deviating a bit from the initial subject but I like how you classified levers instead of simply referring to the size of the group and the way the water is fed to the group (dippers and HX). Again, well done!

Cheers
LMWDP #592

baldheadracing
Supporter ♡

#16: Post by baldheadracing »

I have no experience with the La Pavoni so I can't comment except to say that your temperature readings sound reasonable.

On the Elektra, mine has no gasket between the boiler and group; just an o-ring. I let the machine warm up for over an hour when pulling light roasts - the group gets hot! (1.2 bar boiler pressure) A long time ago I had a temp strip on the group but I can't remember what it read.

In addition, the machine is old enough that the portafilter has no spring. The portafilter can be removed from the group just long enough to put in the filled (single) basket. This helps a little in keeping things hot.

User avatar
TomC
Team HB

#17: Post by TomC »

Jeff wrote: With that in mind, what would those more familiar with the machines, both old and new, suggest for someone that:

* Generally pulls at 1:2.5 or even 1:3 with 17 g of grinds (around 42-51 g in the cup)
* Would consider a machine that could pull those longer ratios with a basket-appropriate dose, if not a 58 mm basket
* Doesn't mind a bit of temperature management
* Doesn't mind dealing with a FloJet or the like
* Doesn't mind getting their hands dirty keeping it running smoothly

I'm not interested in fancy double-pull rituals to get the ratio. Prep, lock, infuse, let the spring work its magic, enjoy...

Price range is relatively open.
You might need to play with my San Marco (Izzo) Leva for a month or more. I'll be taking it off bar soon and I wouldn't mind sharing it with someone close by who I already have good rapport with. Jim King did a lot of work on altering the LSM Leva group to micro-adjust pre-infusion flow. I haven't dove into this yet. But it's an interesting frontier for lighter roasted coffee pulled as espresso. Esprecially when we have the option to run the machine as a single spring at a lower total bar pressure (closer to 8 rather than 11 peak). And get great shots.

Simmer on it, and if you're ever interested, we can set up a coffee play date and I'll bring it down. I'm fully vaccinated x 1000. It would be great to finally have face time.

I'm getting another vintage lever (58mm group) that I will try to deploy before the holidays end this year.