mteahan wrote:Which is why Pragil was so pissed. There he was, sportin' the biggest wood and he got DQ'd for the functional violation of taking Viagra.

Tough thing for an Italian.

Speaking of the limit; that machine we put together for Starbucks would out steam any machine on the planet and still sit on a 30 amp circuit. Did anyone care? No. We developed an automatic/traditional hybrid that would brew up to 5 blends of espresso at 720 shots per hour with disposable brewing groups that could be replaced in about 5 minutes without turning off the machine. Did anyone bite? No.

An espresso machine that delivered shots, hot foamed or flat milk from a bar gun. The world's fastest espresso machine. Any interest? No. The Conti Twin Star has had individually temp controlled brew and steam boilers with demand based watt allocation for over a year and a half, on the market no less. Any reviews or interest among the establishment? No. Brasilia had one 15 years ago.

The only hit was an automated machine using titanium conical mills that brewed 5 liters of espresso in 25 seconds. They went to iced coffee producers in Japan. Six PID'ed boilers and three 300 liter/hour pumps. Five years ago.

None of what we think is new, isn't; merely adapted and tweaked.

Engineers push the envelope all the time and are pretty good at kicking whatever ass they want. The frustration lies in the fact that when they do, nothing comes of it. The problem occurs when trying to build the machine the customer wants. It may not be the best machine, or the most durable or the most practical. It doesn't matter. It's what the customer thinks is important. Even if they are stupid; which is pretty common, but matters little.

The reason why flow rates are important is because the temperature profile is keyed to them. None complained that the test was too hard or too demanding. The word I heard was unrealistic from an extraction viewpoint. They already build machines that deliver 6k shots per day.

This isn't just in the coffee biz. I went skiing this weekend (first time in forever) and there were at least a dozen different shapes and sizes of skis. I'll wager everyone thought theirs was best.

And they probably all correct.

Michael

mteahan wrote:As someone who thinks that temperature profiling is superior to flat line stable brew temperatures, there is an argument to made against the premise of the WBC standards in the first place.

mteahan wrote:Until the information is released, I can only convey what I have been told. I will contact Nuova to see if they will consent to release the data and will try to get a hold of Pragil as well. I have no relationship with anyone else.

Considering that the WBC shopped sponsorships, transparency is in everyone's best interest.



Please understand that I in know way think that the selection was poor--all the machines that were in the testing are good machines. I also know that many factors over and above temperature stability are important. As someone who thinks that temperature profiling is superior to flat line stable brew temperatures, there is an argument to made against the premise of the WBC standards in the first place.

I am still old school in many ways. Put thirty shots from the same barista and grinder on a table in ten minutes and have judges taste the result without knowing the origin. Make it 40; it doesn't matter. Make them all 20 oz. mochas. Doesn't matter. When the Stabuck's technical department disqualified our machine using a PF based temperature device in 1992, they hadn't yet even pulled a shot from the machine. The device indicated a head temp of 237--way too hot to even BE an espresso machine, yet they couldn't explain why the espresso was more consistent and had better developed crema than the machine they had in use, nor could they explain how they were getting spot on shot temperatures from such an 'over-heated' group. I have never been a fan of reverse logic for quality evaluations.

Find a machine that works and figure out why. The presumption of knowing what standard is best only encourages manufacturers to meet the standard, not the result in the cup. When Cimbali, Spaziale, Marzocco and Faema use dramatically different approaches to making espresso--all very good--using any technically based standard is bound to bias one over another.

The Faema, for example, is designed to brew hot initially during pre-infusion, and then drop to a stable extraction temperature. This philosophical approach would on its face disqualify the machine from the WBC standard. Is this the right approach to evaluating machines? I would tend to think not. Cimbali and Faema together have more technical expertise in the design of espresso machines than the rest of the world combined, it would be naive to imply that they don't know what they are doing.




On another note: we have adjustable flow control portafilters that could be modified to accept a temp sensor, allowing you to adjust the flow to mimic whatever flow rate you wish. They are useless to us for the application we had in mind and would be happy to send you a couple to see if they could be of use to you.

Let me know,

Michael

mteahan wrote:I will be giving a technical presentation on European and American standards for espresso machines and processes with Mark Crawford from ESI. We will also be on the floor as exhibitors.

For those that don't know my background:

I started working with espresso machines as a distributor of equipment in Portland in 1987. We designed out own line of espresso carts and doing technical seminars for the US importer of Brasilia espresso machines. Several coffee bars and restaurants later, I left Portland for Los Angeles to eventually become the technical director Rosito Bisani (Brasilia). I wrote for Fresh Cup Magazine delivering technical articles on espresso machines for about a year and a half when the debate centered on the size of boilers and how much steam a machine could deliver. I was against the mainstream then, too.

Michael

another_jim wrote:1. What is the best measure of deviation from perfection? A standard deviation is probably not right, since successive readings are highly correlated. On the other hand, the usual cure, a Mahalanobis transform to "decorrelate" the readings (multiplying the data by the inverse of the covariance matrix) requires a few years of linear algebra to be comprehensible. I won't be sure whether this extra layer of incomprehensibility is worth it.

2. What happens if different shots have observations at different frequencies, or at a changed phase (i.e. some start at the beginning of the shot, others 0.5 seconds in. with all readings offset by a 1/2 second). It may be that one has to run an interpolating filter, then use the filtered values at fixed points instead of the raw data. Again, this is standard stuff, but hard to explain.

3. None of these complications apply to comparing successive **shot averages** for inter-shot variability, since these are only weakly correlated, and then only if the machine is poorly controlled or designed (i.e. if the machine is supposed to "recover" in 1 minute, it means it can also be set to an arbitrary new temperature, reasonably close to the old setting, within a minute).

I hope this is somewhat comprehensible to you. If not, then coming up with a profile independent measure of intra-shot stability will be a hard sell.