I noticed some discussions around temperature profiling, with the theory that increasing the temperature during the shot would lead to better coffee (which was discovered to be false).

As far as I understand, actual extraction temperature won't correspond to input water temperature, since you're starting with (approximately) room temperature grinds. So if you have a constant input water temperature, then the extraction temperature will increase with time. I guess the question is what temperature profile the actual coffee bed exhibits (and that probably varies by depth too). It would be interesting to derive some models for this, and ideally measure it too (having a good model for the temperatures would hopefully make it easier to determine better input temperature profiles).

(And on a side note: I'd love to get one of these machines eventually. I only recently ordered an Expobar DB before learning about the existence of the DE, so I'll probably have to wait a while to upgrade. That should give me plenty of time to learn more about espresso.)

Most of us were precisely discussing that a decreasing temperature should be better, and if I am not mistaken, John and Rao already tested that succesfully.

Other than that, the DE1 is supposed to increase puck temperature quicker than other machines. It does flush the cold water that sits on the tubing before preinfusion, and then target temperature is achieved quicker and it is more stable (traditional machines will always lower temp over time during a shot).

I was on the same situation as you, I bought a NS Oscar II recently... But I went ahead and preordered anyway. I don't want to be reading all the miracles of the DE1+ while I am stuck with a HX machine. Definitely selling an espresso machine is not as difficult as it might look.

Regarding profiles, I've done some experimenting, and while the DE1+ will give a lot more precision, the general idea is that you raise both temp AND pressure for which part of the extraction you want to accentuate. Light roasts will typically have more sours, so lowering temp/pressure in the first 1/3rd of the shot, raising them high during the next 1/3rd (accentuate sweet and caramel), then lowering them again for the final 1/3rd (lower bitters)....may be called an "ideal" profile. (you could also call it a Bell curve)

However each coffee and roast level is different enough, and taste preference is different enough that there will never be a perfect profile. Flow in the first 1/3rd of the shot it also more important to look at than pressure as well.

The real strength of the DE platform will be the community learning and sharing we all come up with. Before it was hard to translate one person's pressure profile to a different machine since pressure/flow and the natural machine temp curve are all data that are needed, but often only one of them is truly known on other machines.

True. The DE is amazing by itself, but the community knowledge will make it probably the best platform available.

Hi John,

While you still can do something about it I'd encourage you to make sure that your portafilters will be able to handle the new VST 25g baskets.

This guy had to modify his Londinium portafilter in order to make it fit : https://kostverlorenvaart.blogspot.bg/2 ... er-to.html

Regards

There shouldn't be any concerns with a factory bottomless. Though I'm not too familiar with the Londinium, the first bottomless pictured in that link looks like a semi-chop job.

A normal factory bottomless should be able handle even when we get to 50g VST baskets.

STORIES FROM THE ROAD
FLORENCE : CAFÉ DITTA ARTIGIANALE


These past few weeks, I've been on the road with my DE1+, starting in London, then 3 cities in France, then the "World of Coffee" show in Budapest, and finally a week in Italy. I've got 10 days to myself now in France, so I can focus on finishing the programming of the DE1+ tablet software and then I'm back to Hong Kong. My partner Bugs Harpley can then take a short holiday (she'll also be exhibiting at the Berlin coffee show) while I run things.

This past wednesday, I got to spend a few hours with Francesco Sanapo http://www.francescosanapo.com the owner of cafe/roaster Ditta Artigianale, seen as one of (if not the) top cafe in Italy. The other Francesco (Masciullo) http://www.dittaartigianale.it/en/news/3/359/2017/2 is Itay's top barista and Italy's candidate for this year's WBC in Seoul.

Francesco Sanapo was quite taken with flow control, as he told me that he regularly talks to La Marzocco and Nuova Simonelli to add user control over flow. They tell him that it's possible with hardware changes, but not as an end user. He invited me to share his booth with two DE1+ machines at HOST Milan http://host.fieramilano.it/en - the most important coffee trade show in Italy. Very flattered, I accepted, and if booth space and schedules permit, we'll do it!

At Ditta they use a La Marzocco Strada with a paddle to make their shots, and Scott Rao had visited a few weeks earlier to tweak their profile for even flow. Scott had created a rise-to-9-bar-then-lower-to-7-bar profile by visually trying to maintain constant flow. It turns out he did a good job, because with my DE1+ was set to create a constant-flow profile, and we watched what kind of pressure curve was needed. In the shot below, the pressure rose to ~8.9 bar and decline to ~7.4 bar : very close to Scott's settings.



In the café they use a Mythos grinder, which is my favorite, but for this demo I had to make do with a spare Mahlkonig K30 grinder. Every shot we pulled that used the K30 grinds had a characteristic jitter of pressure variation between 13 and 20 seconds, which you can see above (this shot also had a channel briefly opening at 23 seconds). The pressure rampup is smooth, though, with the K30. My apologies that I forgot to take screen pictures this past week when I had access to a Mythos, so you'll have to take my word for it, for the time being, that curves of shots pulled from Mythos grounds are very smooth.

My way of comparison, here's what a flow profile shot looks like when using grounds from my Lyn Weber EG-1. Quite smooth.

Why are we Silicone Dipping our Heaters?

Steve Single asked about our choice of Silicone as an insulator, and our interns are confused about how to test the physics of the thing, so I wrote the message below for them, and also for anyone especially interested in why we're dipping our heaters in silicone, something which has not been done in any other espresso machine that we know of.

All insulators (except for a pure vacuum) will eventually reach temperature equilibrium with the thing they are insulating.

The piece of data we want is the "rate of heat loss" that silicone provides, and this is called the "r value". Read about this concept here: https://en.wikipedia.org/wiki/R-value_(insulation)

Silicone is sold as an insulating material, and its r-value compared to other insulators is given here: http://wiki.gekgasifier.com/w/page/6123 ... 20Products

I attach below an excellent academic paper ("New Advances in Silicone-based Thermal Insulation") that discusses various kinds of types of Silicone products for insulation. Here is an important consideration:
"Thermal conductivity of silicone foam is about half the value of pure silicone rubber. ". We have not yet found a source for foaming silicone that we can use, as we have a very strict requirement that the silicone be odorless even when heated to 160°C.

Thus, if we can find a foaming silicone product that "doesn't stink", we will double the insulation and lower the weight and material use. We've got 9 interns here, all engineering students, so we've manpower to throw at this! At the moment we are using non-foaming silicone, which works well, but it's heavier and less insulating than if we could get a foamed variant.

I also attach a PDF explaining all the properties of silicone, but here is the important part for our use:
"Silicone rubber withstands high and low temperatures far better than organic rubbers. Silicone rubber can be used indefinitely at 150°C with almost no change in its properties. It withstands use even at 200°C for 10,000 hours or more, and some products can withstand heat of 350°C for short periods. Silicone rubbers are thus suitable as a material for rubber components used in high temperature environments."

From a safety perspective, we also like that silicone is an electrical insulator. Should a water leak be spraying inside our espresso machine, silicone will not absorb the water and cause an electrical short. Our double-electrical failover components on both heaters are prewired and totally embedded inside the silicone. Chemically, even fully submerged, silicone will absorb no more than 1% of its weight in water.

PDFs:
https://imageserv5.team-logic.com/media ... aper_1.pdf
https://www.shinetsusilicone-global.com ... bber_e.pdf

Have you pulled many shots with the Mahlkonig Peak on the DE1+? I'm curious how you've found it performs. Thanks!

On my tour in December, every Peak I saw at a café was broken and out of commission.

However, at Synesso, they were exclusively using the Peak and I pulled many shots with it, and they were excellent. I assume that Synesso's in-house volume is much lower than a cafés, which is why they were working.

I expect the Peak to be in the same quality range as the Mythos, and I look forward to trying them more once they get their reliability problems sorted. I had heard that they had temporarily pulled the Peak from the market to address the problems, but I'm not sure that's right, as I saw them exhibited at Budapest two weeks ago.