Being the first lever review on the bench, I was feeling a bit jealous and inadequate with all of the other data/graphs that the other reviewers were putting out on their respective machines. As you have seen, these machines are much more sophisticated and are loaded with PIDs, controllers and abundant gauges to help make these measurements possible. So my challenge was to try and see if you could do a pressure profile of the Olympia. With some time on my hands and the wife out of the house, it was perfect time to give it a shot.

There had also been some good discussions on the lever forum with regards to what pressure is actually used during a lever shot, so I convinced Dan to steal a few of his loose parts to see if we can get an idea what pressure is needed on the Olympia and how that pressure varies during a pull.

What we rigged up was an elbow pressure gauge on the bottom of the Olympia portafilter. My wife currently has my digital camera at her parent's house, but I will post some pics of the setup. With a real pressure gauge I hypothesized that I could be a bit more exact on how much downward pressure would be needed to record specific bar pressure on the gauge. Utilizing my handy bathroom scale, that became famous in my Elektra/Pavoni comparison, I was able to plot the following curve:



With this data as my reference curve, I did a rough plot of the pressures that I saw during a good shot at 2 second intervals. To help understand the line, the shot had a 10 second pre-infusion, followed by a first pull...and then you will see the line drop to 0 as I did a second pull until blonding. Take a look:



A couple observations from this data. First, there is very little reference material out there that helps me validate these curves. There have been several posts stating that it takes roughly 40lbs to pull 9 bars, so I was pleased to validate that point. I think the pattern does give you some insight on the unique nature of lever machines. At the start of the pull, infusion is under your control and you can hit the puck immediately with full pressure. There is no ramp-up. Also with these machines, there is variable pressure during the pull. I was using a pulling style of letting the machine do the work and tried to stay with its resistance. The final observation is that with a full manual, I believe that you are able to start at a higher pressure and maintain an overall higher pressure than with an spring loaded machine. Lino had done some tests with an Elektra and I believe he was finding pressure ranges from the high 6s to finishing around 3 for an average pull. By being able to grind finer and keep pressure high, I think you are able to generate the unique mouthfeel that you get with a great lever shot.

So this is my first shot at trying to profile a lever. I will duck under the desk while the real engineers critique my test . In my next posts I will begin discussing procedure to pull a shot and highlight the suggestions from Olympia, combined with some additional hints and tips from my process.

srobinson wrote:So this is my first shot at trying to profile a lever. I will duck under the desk while the real engineers critique my test . In my next posts I will begin discussing procedure to pull a shot and highlight the suggestions from Olympia, combined with some additional hints and tips from my process.

No ducking needed, Duckie!

Truly an excellent analysis, Steve. Thanks!
d

srobinson wrote:So this is my first shot at trying to profile a lever. I will duck under the desk while the real engineers critique my test . In my next posts I will begin discussing procedure to pull a shot and highlight the suggestions from Olympia, combined with some additional hints and tips from my process.

Steve, those graphs are beautiful! I for one would love to frame them and mount them on the wall behind my Cremina. Can you please direct us to the data, or make the numbers available so we can print out suitable copies.

And to any engineer who would criticize your findings, just say "Sorry, Charlie, we don't want engineers with good taste, we want engineers that taste good." (Not sure why but your comments bring to mind that old Starkist Tuna commercial...)

Looking forward to the continuing review.

First of all, thanks for the graphs of the lever pressure on the Cremina 2002! As an owner of a Cremina 67, I would be interested to see if you might be able to post comparison graphs between the 67 and 2002. Given that you have recently replaced the seals and gaskets it would offer insights to current 67 owners as to performance differences of the two models.

Thanks, Texican.
(Steve in Ft. Worth)

You guys are great. If you send me an email, I will gladly send you the full size jpegs if you desire or the PowerPoint source if you would like to embellish with colors. I will try and see what the 67 looks like. I am assuming that it will be fairly close...the first graph should be identical since all the lever equation variables are the same. Will have to test the pull.

How are the Olympias?

Eager for more,

Henry (now a card-carrying member of the LMWDP, Far East representative!)

I'm also eagerly awaiting further findings. I'd be interested in a comparison of the group overheating times where a Pavoni, Cremina and possibly Elektra were run at equivalent boiler pressures...

Br,
Teme

Sorry guys. With my job the worst time of the year is the end of the year close and the new year start...so have been buried under that. Will get a new post out shortly. Sorry for the delay.

Hey Steve! Are we ready for an update yet? Even some informal tidbits about life with the new cremina if not detailed analyses.

PS. Please send cremina pull pressure graph numbers when you get a chance.

Food & Wine's An Obsessive's Guide to Coffee picked the Olympia Cremina among its best espresso machines, saying "WHY WE LOVE IT: This Swiss manual-lever machine has a cult following; only 40 come to the U.S. each year."