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Originally posted by StaticBlue
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I would worry that Nylon would be at risk of melting in a microwave. I wouldn't put my synthetic clothes in the microwave
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Torture testing our new portafilter handles
We're switching to solid vinyl as the material for our portafilter handles. We like the way they feel, look and wear.
However, in torture testing our first batch of 20, we found that we could break the top off. This was because the bolt connecting to the stainless steel head, wasn't that deeply sunk into the vinyl material.
We've remade 20 samples, now with much deeper bolts sunk in, and we've not yet been able to break one.
The solid black vinyl will be the new standard in the future, that comes with our black machines.
So... now onto manufacturing these!
-johnComment
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Better split shots
Our current double spouted portafilter (bottom right photo) does not always do a great job of splitting espresso shots that start slowly. The liquid will often preferentially go to one side, until the flow rate pucks up, and then it'll be even. That makes for even amounts of coffee in the two cups.
This has been something I've wanted to improve, and we've spent some engineering time over the years, making 3D drawings of "split spouts" that would solve this. We've made some 3D printed objects as prototypes, but each had issues, and we hadn't focussed enough resources on this topic, to truly solve it.
A few days ago, we saw that our tea portafilter manufacturer makes the crazy looking portafilter on the top left photo.
And another vendor we work with, makes the portafilter in the top right photo, which looks quite similar to ours, except that it can probably accomodate large filter baskets (20g baskets is the most our double portafilter can take), which would be useful.
We just got them in house, and I've asked one of my engineers to do a number of tests on both. We'll do low-flow-rate "shots" into two cups and weigh the results, trying at different flow rates.
The basic solution to this problem seems to be to have a "miniature cup" that temporarily holds the espresso, and is the cup fills, it spills out (hopefully evenly) into the two exits.
Have you got a double spouted portafilter design that you think really works well? I'd like to hear from any interesting ideas here.
-john
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Just a thought on seeing the double spouts.... sometimes it is hard to place two cups under the split shot and can be messy , especially at the start of a pour. I note(or think i do) the width of the spouts on both examples are not as wide as the whole portafilter basket at top. If a redesign is in the works, maybe the ideal width as well as shape is worth pondering.Comment
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Pitcher rinsers for cocktail bar & and small rinser redesign to prevent clogs
I was talking to Gregoire, in Singapore, about our pitcher rinser. He was asking lots of questions, and I asked him what he was using it for. It turns out he wants to create a coffee bar, and also a cocktail bar prep area, and have them match.
And... that's exactly what I've done for myself. Here are two photos of Bugs' cocktail prep area.
The pitcher rinser we sell is a bit more expensive than most, because I specified all-stainless-steel for all parts. At a recent demo I gave at a London café, I broke their rinser, and it was partially made of plastic (most are) and had to pay to have it repaired.
At any rate, I recently made a cocktail-bar cart for my partner, complete with rinser, glass storage, a knockbox. The knockbox is for banging out ice, mint, fruit slices and other things that get stick in a shaker. There's a "magic bullet" blender under the counter. Four bottles of the most common alcohols she uses (gin, vodka, whisky) are upside down in an automatic shot dispenser.
-john
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Small Rinser Redesign
In other news, at the World of Coffee trade show, I found that my single-dose-bean-weighing was often causing coffee beans to fall into the holes of my pitcher rinser. The beans then float into the drain tube and clog it. Epic failure for a production setting.
So, another "lesson learnt" at the trade show, has us moving to much smaller holes in our pitcher rinser top, to prevent this. We're getting our sample of the new design this week.
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Bamboo scaffolding tradition
In many of the videos I’ve made, you can occasionally see bamboo scaffolding outside the windows. For the past few years, the outside of our building in Hong Kong has been undergoing works, and here, they use bamboo even on skyscrapers. They’re taking the bamboo now, from our 30th floor height. We’ll get a view of the mountains again!
There’s a terrific “infographic explainer” article in SCMP about this tradition, and how it’s cheaper, safer (because it flexes) and much more ecological, than contemporary industrial solutions.
https://multimedia.scmp.com/infograp...ing/index.html
Anyway, this post isn’t about coffee, but it is a great reminder that sometimes traditional ways are best, and let’s make sure we don’t lose our historical knowledge.
-johnComment
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Only the XL case parts are available in white.Originally posted by baristafrenzy View Post
You can buy the natural wood portafilter separately
https://decentespresso.com/portafilter
yes, but it's a separate item you buy and we supply wrenches for you to install it yourself.Originally posted by baristafrenzy View Post
https://decentespresso.com/accessories
Yes, if you get a 20A 110V socket. You should get a 3000W transformer.Originally posted by baristafrenzy View Post
However, it's cheaper to just get a 240V line in the USA, the USA actually runs on 240V. Watch:
There is no DE1CAFE model, it was something we thought we could do years ago.Originally posted by baristafrenzy View Post
No model we make steams during brew and likely never will, because we have no boiler, and are entirely "heat on demand".
Both DE1PRO and DE1XL models have 1500W heaters, but on 240V we observe about a 20% steam speed increase.Originally posted by baristafrenzy View Post
What feature do you mean?Originally posted by baristafrenzy View Post
No.Originally posted by baristafrenzy View Post
The DE1XXL runs at 240V/10A of power, and is our currently shipping highest powered machine.
We are testing a 13A DE1XXXL machine, and next year will start to sell that.
-johnComment
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Do you mean this table? It's bamboo and yes, we stained it several times. It aged VERY BADLY with use and got permanently "dirty" with coffee.Originally posted by lienemann View Post
If you mean the IKEA BROR tables, I did varnish the wood that came with it, which you can see here:
and it looks "ok". But in the end, I decided to get custom cut wood, with a professionally done plastic coating, and that stuff wears amazingly well.
Here's what that looks like:
and that's what we sell FYI
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Decent Suitcase v2 - torture testing
We've started to work on a major revision to the Decent Espresso Machine Suitcase, as part of moving to a new supplier.
We have learned quite a bit over the years, and have a few changes we'd like to make to our suitcase design.
We were happy to find that people who manufacture for Plevo are nearby to us. Plevo is an ultra-high-end suitcase https://www.plevo.co/en-en/cases/plevo-infinite
We've visited this manufacturer. We're impressed by the quality of their work, and we want to collaborate with them.
Some things we want to improve in our suitcase design:- removable wheels, so that we don't have "air space" in the cardboard box, which can be easily crumpled.
- Being mounted on corners, wheels unfortunately also transfer shock into the suitcase itself, and thus increase the damage caused by transport companies throwing your DE1 off a truck.
- The removable wheel design we most like is similar to the Plevo's, with very thick plastic that serves to greatly strengthen the corners, when the wheels are removed.
- You'll receive the wheels inside the suitcase and clip them into place. You can then remove the wheels again, if you need to ship the suitcase back to us.
- the space savings from removing the wheels are significant, removing about 2kg of "volumetric weight", which is about USD$40 in shipping cost, per espresso machine.
- riveted-in corner protectors. We currently add corner protectors in the packing process, but these are usually discarded by the customer on arrival.
- top-side-open, for easier packing. The zip in the center of our current suitcase is a bit difficult to close, since we transitioned to much denser foam. The problem is that the foam needs to be compressed as the suitcase closes, which isn't easy. This new design solves that.
- overall improvement in build quality. While I have no complaints with our current supplier, the Plevo suitcase is *gorgeous* and is a big bump up in quality.
- Yes, the suitcase will cost us substantially more from this manufacturer, but we have enough profitability that I don't mind spending more, to get something nicer. Plus, we'll be able to much easier control quality and deliveries, by using someone nearby.
- We're probably 6 months away from moving to a new design, and still in R&D on this. Success is not assured, but I'm hopeful.
- Note: we won't sell this new suitcase on its own to people, because we ship everything via UPS/Fedex, which means it would cost $300 to ship an empty suitcase to you, which doesn't make financial sense. We'll transition to this new suitcase design, once we run out of the current v1 design, for sending new espresso machines.
ps: If you have a "wishlist" of changes you'd like to see made to our current suitcase design, now would be a great time to voice them. I'm "all ears" !
-johnComment
- removable wheels, so that we don't have "air space" in the cardboard box, which can be easily crumpled.
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FYI our current suitcase is 5kg.My wish would be for it to be as light as possible without compromising the strength. Kind of obvious I guess but for example the Amazon Basics equivalent is built like a tank but at 8kg is takes up a lot of baggage allowance.Comment
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Low mass portafilter ideas
When I met him in Italy, Jonathan Gagné suggested that a "low mass" portafilter head would be very helpful, as he's currently experimenting with "temperature profiling".
The Decent is able to instantly change the water temperature, by changing the hot/cold mix flow rates, but if that new water encounters a lot of mass that is at the "old temperature", then the water temperature will get dragged back to it. That's one of the reasons why we use teflon water tubes (great insulator) with a very small tube size (2.5mm internal dimension) and also why we're moving off brass for the parts inside our group head.
The portafilter, however, being relatively heavy, and made of stainless steel, definitely has significant mass. That the portafilter basket is mostly isolated from it, connected mostly by a thin wire, definitely helps.
Nonetheless, I think Jonathan is right: reducing the mass would only help making the Decent more "nimble" at changing temperatures.
So far, we've made two designs:- a minimal mass one, that removes 36% of the weight, but means that when you put the portafilter on the table to tamp, you'll be placing the basket on the table, not the portafilter. That'll feel a bit different, that's all.
- a conservative reduction of 19%, which preserves all the same touch points, and just removes metal that is 'unneeded'
it seems that a lot of the remaining mass is on the "bolt mount", which is likely thicker than it needs to be. The connection between the handle/bolt and the main ring, definitely needs to be strong, but I'm not sure all that metal is needed around the bolt.
We'll be experimenting a bit more, and making one-off prototypes with CNC manufacturing, to test our results.
We've thought about making these from other materials, but we're quite worried about longevity. Aluminum would definitely lower the weight massively, but would not look great, and because it's softer, we're concerned the "wings" would rub off with use.
If you've got any other ideas, I'd love to hear them.
-johnComment
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John I think you are right that your bolt thread has a lot of support around it, potentially more than required. It is hard to tell from your diagrams the cross sectional size of the support between the bolt mount and portafilter ring, but if the total cross sectional area was made smaller in total by using say three or four small columns it would help to thermally isolate the bolt mount mass (and the mass of the bolt inside the handle, not yet quantified) from the portafilter. Thinner columns would also have greater surface area to radiate heat.Comment
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As Tom might be alluding to, the concept of "thermal mass" is a misnomer, it has nothing to do with mass.
As an example of how this matters, if you substituted aluminium for stainless in the portafiter the aluminium would absorb heat about 25 times faster than the stainless despite being about one third the mass.
BTW you learn this very quickly cutting solid bars with a cutoff saw: you can hold the stainless while cutting with no problems, don't try that with aluminium.
The material property you really want to minimise is thermal diffusivity* which is the quotient of the thermal conductivity and the volumetric heat capacity. Since volumetric heat capacity doesn't change very much** between metals, the thermal conductivity dominates.
Aluminium is one of the best heat conductors known and is an exception to the rule of volumetric heat capacity in the wrong direction so it has a very high thermal diffusivity. Brass is a moderate conductor and has a normal volumetric heat capacity so its thermal diffusivity is mid range. Stainless is a poor heat conductor and has a volumetric heat capacity on the high end of the normal range so its thermal diffusivity is quite low.
Altogether aluminium comes out around 100, brass around 30 and stainless around 4. All this means that stainless is actually about the best material available for this use unless you go to a heat resistant polymer. FWIW titanium would also work well but at great cost.
*This is the constant in the second order differential diffusion equation, δ T / δ t = K δ^2 T / δ x^2. where T is temperature, t is time and x is length. Since that's a second order equation it doesn't have a neat algebraic solution, you need to solve for each case knowing the boundary conditions.
** Heat capacity has mostly to do with the number of atoms in a given volume and how they bounce off each other. More heat makes them bounce faster. Temperature is basically a measure of how fast they are bouncing.
Most metals have roughly the same number of atoms in a given space and they mostly bounce in the three linear dimensions (they have three degrees of freedom) so they mostly have similar volumetric heat capacities.Last edited by Lyrebird; 5 August 2022, 11:46 AM.Comment
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Addendum to the above, I thought of something that might work. Put a layer of a low conductivity ceramic or glass on the part of the portafilter that contacts the filter basket: zirconia or steatite would be my first ports of call.
This is similar to the principle on which Le Creuset glass lined cast iron pans work: the glass lining has very poor thermal conductivity so it forces the heat to diffuse more evenly through the cast iron. My favourite pan for things like frying Halloumi is a big red Le Creuset for this reason.Last edited by Lyrebird; 5 August 2022, 02:56 PM.Comment
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