Decent Espresso Machines (DE1) - Any thoughts?

[>decentespresso]

Real time pressure profiling test

Here's a demonstration of controlling pressure in real time, on the upcoming v1.3 Decent Espresso Machine. We're also working on real time flow control.

Flow control will likely be the default during a shot, because it allows you to control both pre-infusion and the main espresso extraction. Pressure control only works once a puck has been compressed, so it's inherently less flexible.

This feature is still in beta testing, and will be improved further before release.

-john

[EzLau]

I've been working on a web page, with everything about my "convert an IKEA BROR cart into a coffee cart" project, and it's up now:

https://decentespresso.com/coffeecart

and made a video today showing the cart I have at home:

I've ordered 10 replacement tabletops to be made, and will be selling them at cost to folks, to see if this idea has legs.

-john


[ATTACH=CONFIG]24428[/ATTACH]

I’ve noticed that you don’t have any more tabletops for sale anymore on the website. Will you be getting more in? I’m interested!

[>decentespresso]

I’ve noticed that you don’t have any more tabletops for sale anymore on the website. Will you be getting more in? I’m interested!

Well, that's embarrassing.

They're definitely in stock, but someone (ahem, sitting next to me) changed the SKU in the database on me, and thus the web site shopping cart didn't see them. I've fixed the problem now.

We have 10 of the small BROR tables in stock, and next week, should have 10 of the large ones in stock too.

I'm recalculating all the global shipping costs now, as they hugely shot up during Christmas season. Hopefully, in about 24h, those shipping rates will come down by 50%, for the tabletop.

https://decentespresso.com/coffeecart

-john

[>decentespresso]

R&D: Smoothing water flow and lowering sound

In the Decent lab, we're working on flow smoothing and vibration dampening.

This experiment represents a 20db drop in dB sound for pouring hot water at 4ml/s at a defined temperature. It also provides a considerable smoothing (removing of pulses) of the water flow.

This volume level around 37db, at heavy dual pump usage, is *really* quiet. Look at where this lands on a dB chart, between a whisper and a quiet office.

More good news: the changes we have made in this experiment, will be retrofittable to all existing DE1 machines, back to v1.0. There will be a cost associated with the upgrade, as new pumps and a dampening system needs to be installed, but it should be reasonable. And it's not a complicated process: you'll be able to do the upgrade yourself, with no need to send your DE1 back to us.

We still have a lot of work to do, maybe up to a year, before this is widely available. We have to figure out how to make this dampener in production (not as a prototype) and ensure that it is reliable over several hundred thousand espresso shots.

-john

[>decentespresso]

Shin made a short video of his Decent trade show booth in Korea. It's a nice showing of all the stuff we now do.

[>decentespresso]

Zubing's steam wand tip

Zubing Sun, the engineer/entrepreneur behind the truly excellent Force Tamper https://www.instagram.com/starmoonxp is a Decent customer.

We're lucky that Zubing is interested in coffee, as his approach is to use measurement and repeated experimentation, to create his coffee devices. And he shows his results! A typical example, showing improved coffee puck homogeneity with his grooming tool, which is integrated into his tamper:

He has been putting his fine computer-controlled-machining skills to use, in developing a 3 hole, precision calibrated steam wand tip. The early results are impressive.

I'll continue working with Zubing to perfect his steam wand tip, with the intention of selling it as an optional accessory, to Decent customers.

-john

[>decentespresso]

IKEA bigger coffee cart project

We just got our tabletop sample for the "bigger BROR" IKEA table.

The idea is to provide you with a precut, and thicker, tabletop for this $150 IKEA table.
https://www.ikea.com/us/en/p/bror-wo...wood-30333286/

So you can put all your Decent gear into it.

With printed side panels bolted on, and wheels stolen from the $99 smaller BROR, it's pretty snazzy:
More video at: https://youtu.be/gj9xtpdIwvI

In a few weeks, we'll have these larger tabletops in stock. I wanted to get the sample, and properly check it out, before ordering in quantity. We're selling the tabletops at no markup (at cost) + the real shipping cost.

More info about the IKEA coffee cart project at:
https://decentespresso.com/coffeecart

-john

[>decentespresso]

Preheating water tank: new feature, results & next steps




This new feature, which combines the best of both worlds (on demand water heating, and boiler based heating), allows all Decent customers to now hit faster flow rates, at high temperature. Pour overs!

I've added support for preheating the water tank to as much as 60ºC, via the LIMITS tab in ADVANCED shot profiles. This update will be publicly available shortly.

Summary: This feature gives the DE1 some of the advantages of a traditional boiler based espresso machine. Namely: stored energy. However, because we can mix on-demand heating with stored-energy heating, this DE1 changes causes only a short heating delay for the user (2.5 minutes more) instead of the usual ~15 to ~30 minutes delay of a traditional boiler espresso machine.

tldr:
- at 14ºC tank temperature (tap temp), the DE1 can sustain 8 ml/s for 20 seconds. That's plenty for most uses (180ml of water), except for pour overs, which need much more hot water.
- at a 30ºC tank temperature the DE1 to sustain 7.5 ml/s at 90ºC indefinitely. It takes 2.5 minutes for the DE1 to preheat 1 liter of water from room temp (20ºC) to 30ºC.
- the DE1 is not reliable at knowing to preheat the water, because there is no temperature sensor in the tank itself. Setting the tank temp temporarily to 60ºC, to get the water flowing by the temperature probe, and then setting it back to 30ºC (your real goal) is the current work-around.

Next steps:
- it's likely that we can sustain higher flow rates with tank preheating. Once v1.3 is shipping, Ray will modify the firmware to allow the higher speeds, and I'll do more tests.
- changing the tank temperature setting should trigger the DE1 firmware to automatically cycle the water from the tank, through the DE1, to check the current tank tamp and thus decide if a tank warmp is needed.

-------------

Full version:

At tap water temperature (14ºC) the DE1 can only sustain 90º at 8 ml/s, for 20 seconds.

By raising the tank temperature to 30ºC, 90ºC can be delivered endlessly.

Note that heating the tank takes progressively more time, the higher the temperature requested. Note the decreasing slope in the top right of this image, which is showing the 10 minutes it took to reach ~70ºC.

Finally: Note that while I asked for 90ºC at 8 ml/s, the firmware was only ever able to deliver 7.6 ml/s. The pumps should be able to provide more flow: I think this is an intentional firmware limitation that we'll revisit after v1.3 is launched.

-john

[>decentespresso]

DECENT v1.3 news



We just finished building the first, final v1.3 Decent Espresso machine, and it's on its way to me now.

Next week, I'll be making videos with it, such as:

• unboxing v1.3 and setting it up.
• your first espresso
• how to use the real-time controller when making espresso

We're almost finished with the firmware, but still have a few last issues to sort out. Those are detailed below.

In the next two weeks, I expect that the final issues will have been sorted out. I'll be scrutinizing my machine for any hardware issues.

If all looks good, we'll be taking orders for v1.3 machines at the end of January/early February, and shipping the machines as fast as we can make them.

We will be making a few more v1.1 machines, which will be USD$300 less expensive than the v1.3 machines. Later this year, we will also be offering a USD$300 upgrade kit, for v1.1 owners want the group head controller.

REAL TIME CONTROL

• The big change with this model is the new group head controller.
• We have not finalized how the default "real time control" will work.
• Probably, there will be a few iterations on this, over several months, as we get feedback from customers, about what works best.
• What makes this decision difficult is that some people want to tweak an existing automatic shot, while others want to take over completely. And some people want flow control, whereas others want pressure control. Some want fine control, whereas others want coarse control. Some want flow control during preinfusion, and pressure control aftwards.
• For the launch of v1.3, I'm aiming for a simple real-time control approach, and then, in the owner's discussion forum, we can explore ideas, and release them as new firmware updates.

FACTORY CALIBRATION & FLOW MEASURING

• each machine will be calibrated against a precisely measured voltage of 120V or 230V. That way, if your country has 100V (Japan), or some variation between 220V and 240V, we will be able to detect the voltage you're actually getting. With that, we will be able to adjust our physics model of the pumps, and increase the accuracy of our flow measurements. We've written a USB-based configuration utility for our factory to use, and it's not yet perfect and needs a bit more work, as we discover how things actually work in a production setting at the factory.
• v1.0 and v1.1 customers will (coming in March 2020) have a new calibration page where they can adjust the voltage themselves, in the tablet app, so as to benefit from the improvements.

STEAM

• Steam on v1.3 machines will take advantage of the 1500W heaters, up from from 1350W heaters a year ago.
• We have a completely-rewritten-from-scratch steam control method. We're now running steam at a higher pressure, which is increasing heat transfer inside the 1.2M length of tube inside the heater.
• This is gaining us another 10% or so in steaming time.
• Figure about 36 seconds to heat 200ml of milk from refrigerator temperature, down from 46 seconds last year.
• A major goal with this new steam control approach, is to be able to cope better with partially clogged machines. Calcification and dried milk on the tip cause changes in the "physics reality" of the steam path, and this could be seen as oscillations in the steam coming out of the DE1. The new controller is much better able to cope with different physics, adjusting automatically. This aspect of the steam control is not yet working as well as I'd like.
• Not only to avoid do this avoid oscillations, but we have been testing a prototype 2200W heater, and it's been working well. That heater is destined for launch in a DE1CAFE model in 2021.
• All customers (going back to v1.0) will benefit from reduced oscillations, and slightly improved steaming times. v1.1 users from March onwards, had 1500W heaters in their machines, and will also no have a slight speed up. New firmware to enable this for v1.0/v1.1 customers will come out in February, once we've nailed the bugs certain to surface with this big new firmware version.

[>decentespresso]

The final drip tray cover



The resolution of the drip tray cover crisis

We were originally (in August) held hostage by a manufacturer who cancelled our order right when they were supposed to deliver, unless we hugely increased our order quantity. I decided to not be played in that way, and we embarked on a long journey to redo this part, which is now concluding.

Here are photos of the final drip tray cover. We've yesterday received 100pcs in HK.

We ended up with the "welded wire" design, all food-grade polished stainless steel (no coating to wear off). We've given up on the "lost wax" design, as it's never going to be regular looking.

To those of you who sent your ugly drip tray covers to Hong Kong for us to send to new customers, thank you! You enabled us to hold off for months. You enabled us to not be victimized as "hostages" by this supplier. This also allowed us to move off of aluminum, which--even when coated--will eventually look shabby.

In the end, we only ran out of stock of drip trays for a few days, during which we couldn't send out espresso machines. Yow, that was close.

I ordered 500pcs of this model, of which 250pcs are sized for our normal ceramic drip tray, and 250pcs are for the plumbed ceramic drip tray.

Why two sizes?

Because the plumbed drip trays are a about 8 millimeters smaller than the non-plumbed ones, due to different ceramic shrinkage. Each batch is different.

We sent ceramic samples of both to the maker, so that they could make matched pairs for the different two sizes. For people with a draining drip tray, we'll be sending you 2 cover: a slightly smaller drip tray cover in addition to the slightly larger one for the non-draining cover. Ceramic is not plastic: it varies slightly every time you make it. But, I kind of like that aspect of it, as well: it's "real".

Assuming that these all look good, we'll be ordering quite a few more, so that we can send replacements to all of you with ugly drip tray covers. At the moment, I only have 50pcs of each size, so not enough on hand to send spares out. But soon, I will. Thank you for your patience!

-john

[>decentespresso]

USB cable hell



USB cable hell

We've just received a big batch of USB cables from our 3rd and hopefully final supplier.

For those that haven't been following this little saga:
- The first generation (2 years ago) would occasionally melt
- The second generation (a year ago) would occasionally not charge at all (maybe 10% of them)
- This 3rd generation is from a Big Brand, and in our tests, was just perfect. We ordered 100pcs several months ago, sent them to existing customers, and not a single person had a problem.

Now, we receive today 1000pcs, and find that 85% of them are longer than the +/- 10mm tolerance we allowed. Sigh. 15mm too long, is what the top right photo looks like. Just right (3mm too short) is what the other photos look like.

Now we're negotiating to have the manufacturer re-make them to within the specifications that they agreed to.

Thankfully (sort of) we were forced to buy 5 kilometers of cable material in order to buy from these people, as our order was quite "custom", with its thicker conductor than usual, and silicone floppy (not stiff) outer sleeve. That means there's plenty, plenty of spare wire sitting in their stock, for the re-make.

On the positive side, when the cable is the right length, it looks great. We received both white and black cables.

As aside, with the v1.3 model machines we moved the USB port to under the group head. This new position creates a much more pleasing curve for the cable, than the old position to the left of the group head. You can see the old USB position in the bottom right photo.

-john

[>decentespresso]

v1.4 group head research



v1.4 group head research

Though we're about to start releasing v1.3 machines, we've already been working for several months now, on the v1.4 model, which will appear next year (in 2021).

I don't think there's anything wrong with any of previous machines, but there's always room for improvement.

We're actively working on new materials and new shapes and patterns, for the two parts that go into the group head, diffusing the water flow.

All parts will be backward compatible all the way back to v1.0 machines, and you could choose to move to them if you want to. They'll be sold though, not free, but not extortionately priced either.

Our goal is to demonstratively "improve" things. I note that a few Diasporeans are privately taking part in our tests with us. It's not just Decent internal testing.

We're trying to move to the Ultem resin material for these two parts, off of brass, for two reasons:

• Ultem doesn't tarnish like brass, so it stays pretty
• Ultem is an insulator, unlike brass, so temperature stability is improved.

Spacing is part of that research work, as well as testing different theories for water diffusion approaches:

There's a long lead time in manufacturing: R&D needs to be concluded far before you need to start ordering parts.

And R&D, by its very nature, takes an indeterminate amount of time, if it is to provide positive results. And there's always the change that the R&D time spent, won't help you improve anything.

-john

[>decentespresso]

Weighing Espresso Without a Scale



Weighing Espresso Without a Scale

About two weeks ago, I introduced a new feature to the Decent tablet software. You can now stop an espresso based on how many grams you want in the cup, but without a scale!

How do we do this?

The Decent is the only espresso machine I know of that automatically ends preinfusion for you, when the pressure builds up on the puck. This tracks quite well with the puck being fully saturated, and thus coffee starting to drip into your cup.

So, this new feature works by tracking how much water the espresso machine puts into the puck, *after* preinfusion has completed.

As you can see in the chart, this can work quite well. I used a "stop at pour" but also had a scale to track its accuracy. In my experience, within 2g. Where it's farther off, it's always off by the same amount, and you can thus adjust your numbers to get consistent weights.

Stopping espresso by total weight in the cup is considered best practice, as it related directly to the ratio of beans-in-to-drink-out.

The automatic stop does depend on your using preinfusion, and not messing up the settings, such as ending it before the puck is saturated.

The great advantage of this, besides saving money by not buying a scale, is that the scale no longer gets into the way.

In a cafe, a scale gets splashed terribly by group head flushing. It also slows down your workflow.

For drinks that don't use preinfusion (such pour overs) or that don't use preinfusion (such as "classic italian") , the "advanced" profiles let you stop espresso at "total water volume" dispensed. This tracks well with how traditional high end pro espresso machines also let you stop by total volume.

This feature is a free upgrade to all our customers.

-john

[level3ninja]

So, this new feature works by tracking how much water the espresso machine puts into the puck, *after* preinfusion has completed.

As you can see in the chart, this can work quite well. I used a "stop at pour" but also had a scale to track its accuracy. In my experience, within 2g. Where it's farther off, it's always off by the same amount, and you can thus adjust your numbers to get consistent weights.

The automatic stop does depend on your using preinfusion, and not messing up the settings, such as ending it before the puck is saturated.

Does the amount of water a puck holds vary with beans, roasts, grind settings...? Does it require recalibrating when one of these variables change?

[TampIt]

Does the amount of water a puck holds vary with beans, roasts, grind settings...? Does it require recalibrating when one of these variables change?

G'day level3ninja

If you set up your preinfusion to be a set time, no it cannot allow for variations. Instead, if (as I always do) you set up your preinfusion to hit a "break condition" (e.g. to stop preinfusing when the pressure hits 3 bar) rather than an exact time, then any variation in the dose / roast etc will be automatically taken into account by the DE1. The DE1 is possibly the only machine that can automatically stop preinfusion when the puck is fully saturated.

The fact that John has used that process to calculate weight is an added bonus (mucho kudos to John). One of the many ways that the DE1 redefines making a cuppa in a good way.

Another incoming change: In my case, the V1.3 group means that I can set up the DE1 to vary the flow in real time (just like a true manual lever), get the shot settings from the tablet's graph, and then set the DE1 to duplicate those setting for any subsequent shot. Currently I have to guess an initial setting for a new roast and tinker until I nail it - that can take 3 or 4 goes. The new group reduces that to one shot. Another welcome bonus for the DE1.

I hope this helps explain it in a slightly different way.

TampIt