If I missed that...my fault, the Topic is a lengthy read.

I was basing it off of the quote which is linking the Thermosyphon between the Group and the Brew Boiler:

The thermosyphon group works properly when there is a large temperature difference between the boiler and the group

gscace wrote:I think that the best reasonable test would be to run the WBC test series . . . .

Now some have argued that the test isn't relevant for home use, but I disagree. . . . . . .

Once we have a first set of data showing how the temperature changes with duty cycle, we can try corrections in our technique to compensate for machine inadequacies. We can then test the correction by running the WBC series again, implementing the correction where appropriate.

Unfortunately, this is going to be highly variable across users and equipment. Although I did personally run the WBC test several times on both of my machines (Cimbali Junior HXs), I found its results to be more or less useless in coming up with a regimen that would yield true temperature consistency in any sort of usage pattern resembling intermittent low volume use such as one would find (most often) in a home setting. Only after I did a lot of other experimentation did I finally stumble upon an approach that worked for me with my equipment.

I think the WBC test might be worth running once, but if the temperature curves you get from it don't point you in a particular direction, time is probably better spent by most home users in experimenting with different approaches.

gscace wrote:I read lots of comments about engineer types trying to measure this and analyze that, vs tasting coffee. Usually the tone is that it's the coffee stupid. Well it ought to be the coffee stupid, but if your game is really on, I think it's entirely reasonable to examine all of the aspects of your game and try to understand and improve on them. Work towards understanding the process and getting the process more repeatable is all about making things better, so I often find the discussions of extraction and examination of technique to be very useful. On the other hand, if you're sitting there measuring your machine and you're screwing up making coffee, then you have it exactly backwards.

There's obviously nothing wrong with "engineer types" obsessing on this sort of thing, and sometimes this "obsessing" will yield results, such as your own very useful Thermofilter device. What is wrong is the idea that these sorts of technical issues are the most important and that if one just concentrates on them the rest will take care of itself. One reads many such discussions here and on other sites, that totally ignore the fact that it is the coffee, stupid. There are people who fashion themselves to be coffee enthusiasts, who in fact are simply nerds who have transferred some of their interests in electronic doo dads into an apparent interest in coffee, when in fact they wouldn't be able to distinguish between a great espresso and one made on an airplane from a Nespresso machine.

I think this is the reason why comments such as, "it's the coffee, stupid" gets posted, to the extent that the people who post that sort of thing can even tolerate reading through some of the technical threads that appear to lack any apparent real relationship to production of quality coffee beverages.

ken

I don't think the WBC protocol was designed to help you learn to use your particular machine - but rather to come up with a "stress" test result set that can be used to compare repeatable and stable temps across multiple machines.

Endo wrote:I'm was running a Silvia, HX and Double Boiler machine side by side last month on the same Super Jolly grinder. One was not any easier than the other. Whether you are temp surfing, flushing an HX or doing warming flushes on a DB, they all require good Barista skills and knowledge to get a good shot. All machines were equally sensitive to things that made the biggest difference: stale coffee and poor technique.

Let's kill this Silvia myth once and for all. A see a lot of beginners buying DBs based on this advice and then end up both disappointed AND poor.

To say that these three different classes of machine are equally difficult to master is an oversimplification.

No machine, of course, can turn stale coffee into a delicious brew. And no machine is going to give you a great espresso if your grind, dose and distribution are off, though some machines, such as the Aurelia with its gentle preinfusion, may be more forgiving of some imperfections; a machine that ramps up to full brew pressure almost immediately gives the coffee bed no opportunity to consolidate.

Temperature management on an HX and a single-boiler dual-purpose machine like the Silvia involves timing of both the length of the (usually rather copious) flushes and of the rebound time, owing to the fact that they run much hotter brew water than a double-boiler; their brew-water temperature is intricately tied to the superheated steam-boiler temperature. Get distracted during the flush+pull and you've pulled a sink-shot. By contrast, temperature management on a double-boiler machine requires only a very small warming flush and there is no need to be concerned about rebound, or more properly about the inverse of rebound: the double-boiler's group passively cools at a much slower rate than the water in an HX actively heats up. The double-boiler is the easiest to use of the three classes of machine. If a double-boiler is not working out for the consumer, despite its expense, and the reputable vendor has confirmed that the machine is working as it should, then the consumer can be confident that focus must turn to grind, dose, distribution and roast(er) choices.

timo888 wrote:The double-boiler is the easiest to use of the three classes of machine.

If you refer exclusively to brew temperature management, you are obviously correct. But double boilers as a class are not intrinsically easier if you measure by what's in the cup. For example, if I were given the mission of training a newbie for a "competition" scheduled one hour from now using whatever platform I choose, the La Marzocco GB-5 would be one of my last choices, despite that it won WBC sponsorship for 2006-2008.

Interesting read.

I posted this quote on another thread in reference to EricS' temperature thermocouple/thermometer for E-61 HX machines
"Also to be clear - I think this adaptor just might be the single best invention for home HX machines that has yet been devised. It makes temperature control a quantitative science rather then a less precise art of the water dance."

Even as a relative beginner and first thing in the morning in a sleepy haze I never have throwaway shots unless I've changed coffees and the grind is way off. Temperature control is easy at least in my home environment. IMHO my tastes do not need 0.1 degree accuracy. I can certainly enhance flavors and taste the resulting difference for better or worse by a couple of degree alterations. I'm sure others with more refined tastes might see a 1 degree difference as making all the difference. For the average or even enthusiast home consumer I just can't see temperature control as being a real factor here. Flushing and water maintenance absolutely a factor.

Thoughts?

danetrainer wrote:Certainly correct me if I'm wrong...but my Brewtus III DB has the thermosyphon supplying the water to the brew boiler. To me this is an excellent engineering concept to minimize the "shock" of cold plumbed-in water entering the brew boiler and the PID going into a frenzy trying to keep up with a series of shots.

I think that feedwater preheat is a good solution to the problem of cold water entering the brew boiler, but that's not what I'm talking about. If you have an e-61 style group hooked up to the brew boiler and the group thermosyphon is functional, then the convection loop that starts will both warm the group, and cool the water in the boiler. The boiler heating element compensates by rewarming the water, so that's not too much trouble, but the group ends up at substantially colder temperature than it ought to be. When used as originally intended, the group runs at around around 200 deg. f while the hx temp is around 230 or so. In a double boiler system, the boiler will be around 206 or so and the group will be around 180. This compromises the promise of the db solution, which is to provide complete independence of brewing parameters to duty cycle. So the cobbling together of these components really ends up working half-assed.

-Greg

Ken Fox wrote:There's obviously nothing wrong with "engineer types" obsessing on this sort of thing, and sometimes this "obsessing" will yield results, such as your own very useful Thermofilter device. What is wrong is the idea that these sorts of technical issues are the most important and that if one just concentrates on them the rest will take care of itself. One reads many such discussions here and on other sites, that totally ignore the fact that it is the coffee, stupid. There are people who fashion themselves to be coffee enthusiasts, who in fact are simply nerds who have transferred some of their interests in electronic doo dads into an apparent interest in coffee, when in fact they wouldn't be able to distinguish between a great espresso and one made on an airplane from a Nespresso machine.

I think this is the reason why comments such as, "it's the coffee, stupid" gets posted, to the extent that the people who post that sort of thing can even tolerate reading through some of the technical threads that appear to lack any apparent real relationship to production of quality coffee beverages.

ken

You missed the part in my post where I said that if you're obsessing over temperature and you can't make coffee anyway, you're screwing up. There are plenty of examples littering the internet of folks whose fundamentals need much more attention than their machinery does. Yet their emphasis is on their equipment.

-Greg

HB wrote:If you refer exclusively to brew temperature management, you are obviously correct. But double boilers as a class are not intrinsically easier if you measure by what's in the cup. For example, if I were given the mission of training a newbie for a "competition" scheduled one hour from now using whatever platform I choose, the La Marzocco GB-5 would be one of my last choices, despite that it won WBC sponsorship for 2006-2008.

According to Bill Crossland (the guy who designed the GS3), there are at least 15 different brewing parameters that affect espresso taste. Examples besides temperature and pressure include the coffee, roasting, age, grind, brewing basket geometry, group internal geometry, pump actuation scheme, pump type, and others. Only a few of these are easily modified by the user. So we do spend extra time talking about them - maybe too much time. Some machines appear to perform magically because of the serendipitous marriage of engineering choices in the design. I suspect that the Elektra is one such machine. But just because a machine posesses certain specs on paper doesn't mean it's gonna rock your world. At home, I produce better coffee than I do at work. I use the same coffee, conical grinders at both locations, but two different machines. Both are double boiler, rotary pump machines. It's the difference in the details and the integration of ALL brewing parameters that makes one do a better job than the other.

Jim mentioned cases in which temperature and pressure were well controlled, but the results were not as good as other cases in which T and P were less well handled. What that should tell you is that T and P are not the whole story. Jim's example should reinforce the idea that the art of the machine designer is in weighing the value of sometimes contradictory engineering requirements, and then making the best fit.

In practice, the promised claims of various principles don't always measure up to expectations. In my day job I work in humidity measurement at a national metrology laboratory (NIST). We often see measuring instruments that are based on what we call first-principles. First-principles measurements are the most fundamental of measurements. Examples are length, time, mass, temperature. First-principles quantities are different from "derived" units. For example, force is mass times acceleration, so it is derived of mass, length and time. Things that are based on first-principles are supposed to carry a lot of weight in science and engineering because they are so fundamental, but what we routinely see is that implementations of first-principles techniques fall short in their promise, unless the implementations are executed extremely well. For example, the idea of measuring humidity in terms of dew-point temperature by measuring the temperature of a surface on which there is condensed water (dew or frost) at equilibrium with the surrounding air, is a first principles method of measuring humidity because the unit is temperature. However, the promise falls short because the surface must be maintained in perfect equilibrium with the surroundings, which is very difficult to do. So we get temperature approximating dew-point, not the real thing. In coffee, the promise of the double boiler system is that the coffee produced by such a machine is unaffected by duty cycle, steaming temperature and steaming duty cycle. The reality is that the marriage of engineering choices prevents the ideal from being achieved. And since the double boiler promise addresses temperature, but doesn't necessarily address all other brewing parameters, the coffee produced by a double boiler machine could be crap, unless the designer did a good job of handling the other requirements as well. Same is true for HX designs. The ones that pay the most appropriate attention to all parameters will produce the best cup. The current economics of coffee machines prevent the real and ideal from converging. Companies have to perceive that they'll be able to make money if they throw their resources at engineering an ubermachine. We'll see better machines when it can be demonstrated that the current state of coffee machines is one of the major drivers in improving coffee (another question that is fertile ground for discussion), and when some company thinks that they can make money by producing such a machine. We'll see more widespread improvement when that company then demonstrates the money-making potential.

Now I better get to work.

-Greg

gscace wrote:You missed the part in my post where I said that if you're obsessing over temperature and you can't make coffee anyway, you're screwing up. There are plenty of examples littering the internet of folks whose fundamentals need much more attention than their machinery does. Yet their emphasis is on their equipment.

-Greg

Greg,

I absolutely did not miss that part. My post merely reinforced those comments, above.

ken