Initial Impressions of the Ponte Vecchio Lusso - Page 5

[Adrock]

I have a somewhat tangential question, and I apologize if it has been answered on another spring vs. manual thread. Is a Europiccola more forgiving with the grind than an Export/Lusso? I'm thinking about purchasing one, and I believe I read that manual levers are more forgiving because one can add/subtract force to somewhat compensate for problems with the grind. I would probably take Timo's advice from a previous thread and spring for a manual grinder- how would a Lusso/Export perform with that type of grinder? Thank you. Great thread and great review, by the way!

[timo888]

With a manual lever the barista can increase the pressure or reduce the pressure, but with a spring-lever one can only reduce the pressure, pace peacecup's acrobatic maneuver with his Ponte Vecchio Export where he presses down on the piston rod directly. The ability to make ad hoc adjustments might save the shot from going down the sink, but such adjusments are not going to produce coffee nectar. So I would not base the selection on this difference. If faced with a choice between a domestic spring lever like the Ponte Vecchio Lusso or the Export, and a manual lever such as the Europiccola, I would focus on these differences:

difference between ~6 bars (spring) and ~9 bars (manual)

The non-expert barista interested in forgiveness factors will find it easier to avoid channeling and overextraction with the spring lever's 6 bars and taller basket, IMO. 9 bars with 51mm basket can produce a more robust shot and more mousselike crema. The spring's 6 bars with 45mm basket produces a more syrupy crema and a consistently smooth shot. Greater crema volume is not an indication of a superior or better-tasting espresso; sometimes it indicates that the roast is still very gassy and needs a few more days rest

convenience of steaming while the shot is completing (spring-lever can do this)

My wife is impressed by the ease and speed of preparation with the Lusso. The spring allows ones hands to be free much more. Making espresso is less work with a spring. The more espresso drinkers the barista is preparing coffee for, the greater the benefit of this leisurely aspect of the spring lever.

aesthetics

boxy or belle ?

GRINDER
A manual grinder (KYM, Trosser, Zassenhaus) with new sharp burrs would certainly be fine. It is difficult to know when buying a used manual grinder on eBay how worn the burrs are.

Regards
Timo

[hbuchtel]

difference between ~6 bars (spring) and ~9 bars (manual)
Timo

Hey Timo, why do you think the PV produces 6 bar? (Did I miss a post somewhere?)

Henry

[timo888]

If you define the end of the shot as the point at which it begins to blonde, then I maintain that with the way the PV group under-extracts, there is no way you can get a brew ratio near 60%. If you can show me how to brew a shot on the PV that ends at the point of blonding and where the shot weighs significantly less than 170% of the dose weight, I would love to see it (and try it).

Certainly one wants to pull the cup if the flow blondes. But I don't define the shot as the point at which it begins to blonde. What if my shots don't blonde? What if I am happy (as I am) with an extraction that gives me a 1-oz shot after two full pulls, even if I might have given another semi-pull and gotten a few additional milliliters of good espresso from the dose in the basket? Who cares if I leave a half-gram of unspent coffee in the basket? That is how a 6 bar machine "under-extracts" -- it wastes a smidgen of coffee. The espresso itself is not 'underextracted'.

The until-the-flow-blondes definition might make practical economic sense for an espresso chain concerned about wastage of fractional grams of coffee adding up to real money after tens or hundreds of thousands of shots pulled, but I see no compelling reason to impose it upon the home espresso enthusiast.

Regards
Timo

[Dogshot]

The until-the-flow-blondes definition might make practical economic sense for an espresso chain concerned about wastage of fractional grams of coffee adding up to real money after tens or hundreds of thousands of shots pulled, but I see no compelling reason to impose it upon the home espresso enthusiast.

Nor do I. However, the blonding point is a frame of reference that allows us to share the concept of brew ratios, and therefore to discuss shots that share certain qualities. By working from the same point of reference, we can provide each other with dis/confirmatory perceptions. This can help to build our knowledge of the PV group, and how to get the most from our machines. For example, I am trying to answer the following question - can the PV group user produce a shot with a brew ratio as high as or greater than 60% (Andy's definition of the starting point of a ristretto)?

Mark

[hbuchtel]

Certainly one wants to pull the cup if the flow blondes. But I don't define the shot as the point at which it begins to blonde. What if my shots don't blonde? What if I am happy (as I am) with an extraction that gives me a 1-oz shot after two full pulls, even if I might have given another semi-pull and gotten a few additional milliliters of good espresso from the dose in the basket? Who cares if I leave a half-gram of unspent coffee in the basket? That is how a 6 bar machine "under-extracts" -- it wastes a smidgen of coffee. The espresso itself is not 'underextracted'.

The until-the-flow-blondes definition might make practical economic sense for an espresso chain concerned about wastage of fractional grams of coffee adding up to real money after tens or hundreds of thousands of shots pulled, but I see no compelling reason to impose it upon the home espresso enthusiast.

Regards
Timo

"Blonde" is not a rule or even the same color to everybody, it is only about making a connection between color and taste... and using it this knowledge to end the shot when you think it tastes best.

As far as I can tell a clear definition of when to end a shot is missing from Andy's tables, which might be contributing to the confusion here.

Henry

EDIT: here is the link for reference- http://www.home-barista.com/forum...verages-t2402.html

[timo888]

Nor do I. However, the blonding point is a frame of reference that allows us to share the concept of brew ratios, and therefore to discuss shots that share certain qualities. By working from the same point of reference, we can provide each other with dis/confirmatory perceptions. This can help to build our knowledge of the PV group, and how to get the most from our machines. For example, I am trying to answer the following question - can the PV group user produce a shot with a brew ratio as high as or greater than 60% (Andy's definition of the starting point of a ristretto)?

Yes, if you allow me to determine the dose and grind and tamp and the water volume I send through the cake and the pressure I send it through with (e.g. partial pull versus full pull), and if you do not require me to keep sending water through the cake into the cup until the flow blondes, then of course the Ponte Vecchio Lusso can pull a ristretto, i.e. a richer tasting more intense extraction whose dose-weight to beverage-weight ratio would meet or exceed Andy's range which is a 1-to-1 ratio, ±.

But the "algorithm" would vary by blend, roast depth, roast age, grind, dose, and temperature, all of which affect the extraction.

There are more opportunities for nuance and variability in a spring-lever machine with tapering brew pressure than there are in an electric pump machine with relatively constant pressure and water flow. Sharing knowledge about a spring lever is a much more nebulous affair than sharing knowledge about an electric pump machine whose performance is more easily quantified and analyzed; and yet even with an electric pump, relatively minor differences in, say, the pressure ramp up curve, can result in differences in the cup.

Regards
Timo

[peacecup]

The whole brew ratio question has been of interest to me since I started using the Ponte Vecchio, because I am using a relatively high dose (15g) to make a relatively small shot (1-1.5 oz.). For a long time I took three or even four pulls because I was accustomed to brew ratios on the order of 15g:2 oz. Two-pull shots tasted a bit too syrupy for me. I have learned to like them more, and now they tend to be the norm. I did this partly to reduce the amount of caffeine per espresso as well, so that I could have more smaller doses rather than fewer larger doses.

Even if I constrain myself to two pulls, however, there are (nearly) endless combinations of grind/dose/tamp that can play out differently in the cup.

Today's experiments are with coarser grinds, trying to see if I get sweeter shots via the more complete extraction hypothesis (which I am not convinced applies to 45 mm baskets anyway). Besides, I want to give the cotter pin a rest!

I might even try dosing less (heaven forbid).

PC

[timo888]

"Blonde" is not a rule or even the same color to everybody, it is only about making a connection between color and taste... and using it this knowledge to end the shot when you think it tastes best.

As far as I can tell a clear definition of when to end a shot is missing from Andy's tables, which might be contributing to the confusion here.

I agree with you, Henry, about the blonde gradient. A rough measure. But I think there is no need to determine when to end the shot when focusing on brew-ratios because it isn't really necessary. You need the dose and the beverage. The volume and weight of the beverage can vary according to the dose. You could pull a ristretto on that super-mini machine that was brought to our collective attention a few months ago, if'n you had a teeny grinder and miniature beans.

Regards
Timo

[Dogshot]

What if my shots don't blonde?

Well, then only 2 more miracles, and your espresso machine qualifies for canonization .

What if I am happy (as I am) with an extraction that gives me a 1-oz shot after two full pulls, even if I might have given another semi-pull and gotten a few additional milliliters of good espresso from the dose in the basket?

What decision rule to you use then to decide when to stop a shot?


Mark

[timo888]

What decision rule to you use then to decide when to stop a shot?

I try to modify the dose and grind so that each pull takes 12-15 seconds to complete, the shot doesn't blonde, and the espresso in the cup tastes good to me.

Regards
Timo

[mousetail]

Hey Timo, why do you think the PV produces 6 bar? (Did I miss a post somewhere?)

Henry

I think the Lusso does produce ~9bar and I believe I can prove it, with a bit of school physics and maths. This is not a late April Fool, although it might sound like it at times.

This is what you do:

Stand on an accurate bathroom scales (clothed is fine), and note how much the recorded weight reduces as you pull the lever. You need to be careful not to touch anything other than the lever to get an accurate reading. On my 5-year-old just-overhauled Lusso this was 9 Kg

Here's where the physics comes in. The lever handle to fulcrum distance is 200mm, and the fulcrum to piston lifter is 15mm. So..

pressure exerted by compressed spring x 15 = 9 Kg x 200 ... If my calculation is right, the spring pressure on my machine is 122 Kg

The piston diameter is 40mm which means an area (pi x radius²) of 12.57 cm²

So I think the brew pressure on my machine is 122/12.57 or 9.71 Kg/cm² which is equivalent to about 9.5 bar

Good old PV? Or is my method not scientific enough. (I got lousy grades at school)

regards
Bob

[timo888]

Hey Timo, why do you think the PV produces 6 bar? (Did I miss a post somewhere?)

Henry

I think the Lusso does produce ~9bar and I believe I can prove it, with a bit of school physics and maths. This is not a late April Fool, although it might sound like it at times.

This is what you do:

Stand on an accurate bathroom scales (clothed is fine), and note how much the recorded weight reduces as you pull the lever. You need to be careful not to touch anything other than the lever to get an accurate reading. On my 5-year-old just-overhauled Lusso this was 9 Kg

Here's where the physics comes in. The lever handle to fulcrum distance is 200mm, and the fulcrum to piston lifter is 15mm. So..

pressure exerted by compressed spring x 15 = 9 Kg x 200 ... If my calculation is right, the spring pressure on my machine is 122 Kg

The piston diameter is 40mm which means an area (pi x radius²) of 12.57 cm²

So I think the brew pressure on my machine is 122/12.57 or 9.71 Kg/cm² which is equivalent to about 9.5 bar

Good old PV? Or is my method not scientific enough. (I got lousy grades at school)

A clever approach, Bob, which makes sense in the abstract, but it has opportunities for significant real-world measurement errors which make me want to distrust it: depending upon where I position myself relative to the machine, the readings vary considerably. If I face the front of the machine, I get one set of readings hovering around 9Kg but if I face the side of the machine when I press down on the lever handle, I get a lower set of readings around 7Kg. Taking the measurement from the side is the more physically stable of the two approaches, at least for me and my digital bathroom scale.

On my Lusso, the distance on center between the pins is 1.65cm and the distance from the fulcrum to the end of the handle is 22.5cm. But we can say we are not exerting pressure at the extreme tip of the handle but near the 20cm mark, as you suggest.

The Lusso's relatively narrow diameter piston bore would produce relatively greater brew pressure, but I get the sense from the extraction that the pressure is not much different from La Peppina's. Peppina appears to have a heftier spring but also a cylinder bore that is ~10mm wider, which would offset the additional spring force and reduce brew pressure.

Regards
Timo

[timo888]

Hey Timo, why do you think the PV produces 6 bar? (Did I miss a post somewhere?)

Henry

Hi Henry,
I missed this post. I answer it in my response to Bob's lever-mechanics approach. The same caveats apply to the imaginary hydraulic pump approach you are using that Jim Schulman suggested. Either of the approaches works in the abstract, but there is uncertainty, I think, when measuring the weight required to compress the spring.
Regards
Timo

[mousetail]

.... but there is uncertainty, I think, when measuring the weight required to compress the spring.
Regards
Timo

I've just replaced the spring in my machine, so I might play around with the old one and a torque wrench to see what compression reading I get. If I can just figure out a way to do it that my life insurance company will be happy with!
Bob

[timo888]

I've just replaced the spring in my machine, so I might play around with the old one and a torque wrench to see what compression reading I get. If I can just figure out a way to do it that my life insurance company will be happy with!

May the heavens protect you on this mission.

I would be happy to know the spring measurements, to compare them with another set that H-Ber sneakymagic sent to me for a SAMA.


Outer diameter of spring
Length of spring
Thickness of wire
Number of active coils (excluding the filed down ones)
Distance between coils


Regards
Timo

[mousetail]

May the heavens protect you on this mission. It's been nice knowing you...

I would be happy to know the spring measurements, to compare them with another set that H-Ber sneakymagic sent to me for a SAMA.


Outer diameter of spring 35mm
Length of spring 73mm (although the new repacement was about 3mm longer*)
Thickness of wire 5.5mm
Number of active coils (excluding the filed down ones) 5
Distance between coils 13mm (possibly slightly more on new one*)

best wishes
Bob

[DaveC]

Wow guys, simply blew my brains away with all the science and calculations.

However, I like the principle of "keep it simple", because i'm a bit of a simple bugger really. My calculation would be (but then remember my brains are now on the ceiling):

Take the old spring, place on scales and compress it to the same amount you think it compresses on PV or about 90% of its maximum (or if it stretches use a fishing type spring balance and pull it (same principle)

Read the weight shown in lbs

Caclulate the surface area of the piston (chamber bore)

Divide that into the weight shown on the scale to get the likely max psi exerted by the spring

OK probably not going to convince the guys at CERN or Professor Richard Wolfson (my hero) they may say it's not 100% accurate, but should do the trick. Of course the spring gradually exerts less pressure as it extends, but...hey isn't that a good thing?

[timo888]

<image>

Wow guys, simply blew my brains away with all the science and calculations.

However, I like the principle of "keep it simple", because i'm a bit of a simple bugger really. My calculation would be (but then remember my brains are now on the ceiling):

Take the old spring, place on scales and compress it to the same amount you think it compresses on PV or about 90% of its maximum (or if it stretches use a fishing type spring balance and pull it (same principle)

Read the weight shown in lbs

Caclulate the surface area of the piston (chamber bore)

Divide that into the weight shown on the scale to get the likely max psi exerted by the spring

OK probably not going to convince the guys at CERN or Professor Richard Wolfson (my hero) they may say it's not 100% accurate, but should do the trick. Of course the spring gradually exerts less pressure as it extends, but...hey isn't that a good thing?

The equations won't really make your head explode. The Ratio of the Effort Arm Length to the Work Arm Length, multiplied by the weight applied to the lever handle, yields the amount of work performed (expressed in pounds or kilos). This tells us how much the spring is pushing back. After that force has been determined, Bob's approach and yours become the same. Divide the area of the piston cylinder bore into the Force.

Bob's approach is a little safer than yours. It may sound simpler your way, Dave, but it is easier said than done because the spring tends to scoot when placed on the scale and is being compressed by hand (or foot). Some sort of contraption is required to stabilize the spring ...

And yes, that the spring's force tapers off does have its benefits.

Regards
Timo

[DaveC]

The equations won't really make your head explode.

Bob's approach is a little safer than yours. It may sound simpler your way, Dave, but it is easier said than done because the spring tends to scoot when placed on the scale and is being compressed by hand (or foot). Some sort of contraption is required to stabilize the spring ...

I know, but I needed an excuse to use the avatar You are right of course, the forces involved are quite high with the PVs piston area needing around 250lb of force....thats quite a lot and it would be dangerous..