Decent Espresso Machines (DE1) - Any thoughts?

[>decentespresso]

The Decent Tamper v2....

... makes tamping exceedingly boring.

https://decentespresso.com/cart?s=200+1

[matth3wh]

Hi John
I like boring tamping so thumbs up to that.

What's the difference between v1 and v2? The lip locking in place over the top of the basket ?

[>decentespresso]

is there any way to use the Skale output to manage flow in real time? (I REALLY want to use flow instead of pressure, but it seems a bit variable so far)

I don't think that'd be a good idea.

Firstly, you'd have no idea about water flow during preinfusion, when no water (coffee) is flowing into the cup.

Secondly, if preinfusion didn't fully saturate the cup, your flow would be incorrect as it wouldn't take into account the continuing "sucking up of water" that the puck is doing.

I do have plans to have preinfusion optionally end on "first drop into the cup", but that's a bit different.

-john

[>decentespresso]

Hi John I like boring tamping so thumbs up to that.
What's the difference between v1 and v2? The lip locking in place over the top of the basket ?

The tamping base is "locked" to the handle with this version: it's the "leveling plate" that is now connected to a 25lb spring.

So... it's now impossible to tamp in a non level way.

Also.. I learned something important about CNC lathing with the v1 tampers. With lathes, the usual +/- tolerances don't apply, there is ONLY a +tolerance number. Thus, if you specify (as I did for our v1 tampers) a 58.5mm base, in reality the lathe will give you bases of sizes between 58.52mm to 58.57mm.

That's getting a bit tight, and professional baristas have complained that our v1.0 tampers have a suction problem because of this tight fit. Rao didn't endorse our tamper because of this: it slowed down a professional's workflow. Amateurs liked the tight fit, since they are working slower, but pros did not.

These new v2 tampers are speced at a CNC lathe size of 58.4mm, which has them land *in reality* at 58.42mm to 58.47mm (FYI confirmed so far on the 20 or so that I've measured today). No more suction problem, and pros tamp faster on these than traditional tampers, since they don't need to do the "finger dance" to ensure they're tamping at 90º.

-john

[gc]

Yes, the new flow meter has identical operating specs, uses the same plug and mounting. It just "works better". No firmware change needed. Two minute swap, you can definitely do it yourself.

-john

Great! So how do we get one?

I do have plans to have preinfusion optionally end on "first drop into the cup", but that's a bit different.

Would it be possible to have the Skale data take over from the end of preinfusion then to control flow as it can already control the end of shot by weight?

Will you still be supplying an "update kit" to version 1.0 owners? I ask this because I could get a V2 tamper, new flow meter and the update kit all shipped together when it was all available.

[Lyrebird]

I learned something important about CNC lathing with the v1 tampers. With lathes, the usual +/- tolerances don't apply, there is ONLY a +tolerance number. Thus, if you specify (as I did for our v1 tampers) a 58.5mm base, in reality the lathe will give you bases of sizes between 58.52mm to 58.57mm.


-john

We were taught this as "minimal material tolerance" eg the tolerance is specified so there's always more material left, not less. The obvious reason being you can always remove more but it's pretty hard to put back on.

You should be able to change this in your drawing program: as an example, in Autocad it's a tab predictably called "tolerances" under the "annotate" tab.

[>decentespresso]

Testing 5 hole baskets for pour overs

I'm working with Scott Rao to try to improve our espresso machines' ability to make pour over coffee. These custom made portafilter baskets are meant to have controllable pressure, in order for Scott to have control over agitation of the grounds. We've made 3 different hole sizes for Scott to try out.

My hunch is that the holes could stand to go a bit larger. We calibrated these holes for 4 bar of pressure, so we'd be able to go up or down. However, now that I have them in hand and I can test, I think larger holes would be better, because a substantial jet is formed at just 1 bar.

I told Rao this via email, and suggested that he might want to enlarge the holes with a sewing needle.

These baskets are just our first attempt. There will likely be many more revisions before we're happy.

Coffee ground turbulence during a pour over is super important. The famous "Rao V60 pour over” https://www.youtube.com/watch?v=c0Qe_ASxfNM addresses this, for manual pour-overs.

The question is: can the optimum turbulence be mechanized with our pressure and flow controlled espresso machine, and a bit of specialized hardware? We don't know yet.

-john

[>decentespresso]

Great! So how do we get one?

First: we need to test them further, and decide whether they really are better.

Then: they'll be available (like all our parts) at https://decentespresso.com/cart?show=all

Would it be possible to have the Skale data take over from the end of preinfusion then to control flow as it can already control the end of shot by weight?

It is technically possible, but there are a few steps that need to happen before we can do that, most notably: real time user control over the flow rate. Once we have that, it won't be too difficult.

Note that I'm not sure that it would be all that useful a feature.

When your puck is fully saturated, water flow rate into the group will equal flow rate out into the cup. And you *want* a fully saturated puck when making espresso. So... I'm not sure I yet see the point to the scale controlling flow.

Doing so also adds a new "point of failure" since measuring flow into the cup requires bluetooth (or USB, and hence a wire) and is susceptible to table vibration. I worry that this would make espresso making less reliable, rather than more.

Will you still be supplying an "update kit" to version 1.0 owners? I ask this because I could get a V2 tamper, new flow meter and the update kit all shipped together when it was all available.

Yes, there will be a free update kit to all v1.0 owners once we have stock of all the replacements. Probably November. Since the v1.1 flowmeter only costs us a few dollars, I'd likely just include it for free on request, for our customers who want to swap it out themselves.

-john

[gc]

First: we need to test them further, and decide whether they really are better.

Then: they'll be available (like all our parts) at https://decentespresso.com/cart?show=all


It is technically possible, but there are a few steps that need to happen before we can do that, most notably: real time user control over the flow rate. Once we have that, it won't be too difficult.

Note that I'm not sure that it would be all that useful a feature.

When your puck is fully saturated, water flow rate into the group will equal flow rate out into the cup. And you *want* a fully saturated puck when making espresso. So... I'm not sure I yet see the point to the scale controlling flow.

Doing so also adds a new "point of failure" since measuring flow into the cup requires bluetooth (or USB, and hence a wire) and is susceptible to table vibration. I worry that this would make espresso making less reliable, rather than more.



Yes, there will be a free update kit to all v1.0 owners once we have stock of all the replacements. Probably November. Since the v1.1 flowmeter only costs us a few dollars, I'd likely just include it for free on request, for our customers who want to swap it out themselves.

-john

I do understand and agree with your points above. The reason I suggested the Skale to control flow was based on my observation so far, that the brown Skale output graph and the Blue DE flow output are usually different [but not always for me] and for some reason, I just trusted the Skale as being the more accurate.

Perhaps a software/firmware update will fix this in future, or maybe I should just recalibrate again - except sometimes both readings do coincide.

Good news about the update kit too. Keep us posted on that flow meter testing.

Thanks for your input John.

[>decentespresso]

The reason I suggested the Skale to control flow was based on my observation so far, that the brown Skale output graph and the Blue DE flow output are usually different [but not always for me] and for some reason, I just trusted the Skale as being the more accurate. Perhaps a software/firmware update will fix this in future, or maybe I should just recalibrate again - except sometimes both readings do coincide.

We do use the brown Skale line to calibrate the blue line, at the factory. However, the world being a complicated place, things like dissolved oxygen, water temperature, pump temperature, water mixing and pressure all conspire to make the calculation from "pump strokes per second" to "flow per second" into a very complicated bit of maths. In some circumstances, we nail it, whilst in others we're as much as 20% off. This is what we're hoping to improve with further months of R&D.

-john

[>decentespresso]

Weighing from below

I knew that it was possible to place the bluetooth scale we sell under the drip tray, but the fit wasn't right, and it didn't work that well. These problems seem to now have been resolved by the Decent user community.

The advantage of having the scale underneath is that you now have access to the entire drip tray, and you don't have worry about spilling coffee on your scale. It's invisible, and out of the way. You can now also USB power your scale, since the USB cable will not be in the way.

Decent customer Michel Wyss did the first draft of an idea, and shared his drawing as a STEP file. He replaced the top of the skale with his own design, which was a bit taller, and sized to fit the ceramic drip tray correctly.

Steffen Lav revised this design, printed it and posted this video today on youtube of it working:

Anyone with one of our "skales" and a decent espresso machine can download the shared STEP file and have it printed inexpensively, locally, with a service such as https://www.3dhubs.com/

I'll be testing this myself in a few days as well.

-john

[>decentespresso]

Heater Rethink



We're currently using off-the-shelf heaters (top left in the photo) at 1350W of power. We just found another supplier for this standard design, at both 1350W and 1500W, and we'll be trying that for v1.1. It'd only give us 9% more power, but why not take it...

Longer term, though, we want to switch to our own design. There are a few reasons: (1) we'd like to go to 2200W of steam power or possibly (2) two heaters at 1100W and (3) we'd like to simplify/speed up assembly/wiring/insulation of the heaters (3) make repairs easier.

Our current design takes an hour and a bit to assemble each heater, build its insulating box and wire it all up. There are two in each machine. Wouldn't mind cutting that time down some.

In the various photos attached, you can see our current heater, two different designs for an enclosure (snap lock vs cable tie) and our experiments using 3D printing to test these ideas out.

We still have a few iterations to go on this before we're happy. The mould fee to try this is USD$15,000 (!!!) and several months, so this is something that we are slooooowly approaching.

The intention is for these heaters to make their way into our v1.3 machines, but they'll also be backward-compatible with all previous models too.

-john

[HBexile2]

Unfortunately, manufacturing is always a set of compromises, and this design, which we were told was doable in stainless, we now find that no manufacturer wants to take the risk to do for us.

The stainless casting companies have wanted us to make quite a few modifications to the current design, which would make it a lot less functional and uglier. For example, switching to stamped stainless is doable, but would cause water to bead up on the "wires". Or if we stay with casting, adding crossbars and thickening the wires quite a bit.

Stainless is doable, but it's (a) very time consuming and (b) not assured of success, (c) so far, looks likely to require ugly modifications of the current design.

Why would you cast the drip tray in steel? Stamping sheet metal is the way to go as you can get nice curved edges on the bars for water draining - something laser cutting can't get. Classic Linea has a great drip tray and is done by stamping. GS3 not so good and was done by laser cutting the holes.

[>decentespresso]

Why would you cast the drip tray in steel? Stamping sheet metal is the way to go as you can get nice curved edges on the bars for water draining - something laser cutting can't get. Classic Linea has a great drip tray and is done by stamping. GS3 not so good and was done by laser cutting the holes.

There was a huge conversation thread about the different types of drip tray cover styles on Home Barista. Can I point you to it for an answer?
https://www.home-barista.com/marketp...0.html#p514131

Regarding your suggestion, it reads:

2. Punched and bent stainless grate. By this I mean that the grate is made from a solid sheet of stainless, which has strips punched out of it and bent down. This minimises the flat areas and the bent bits block most of the view of the contents of the drip tray. These are a sensible compromise between cleanliness and obstructing the view of the mess in the drip tray. I think they aren't as good as the wire grate because they still need a bit of a wipe down. See the original linea (and maybe breville dual boiler; really a hybrid between 2 and 3).

That conversation on Home Barista is why we went with a "wire" design.

On the pages that follow that first message you can read so much design discussion about this little part.

That being said, we have drawn up a punched metal version of our current drip tray, which you can see below. It's possible we might do this someday, though this design has its own compromises too.

-john

[>decentespresso]

New recipe: Gentle and Sweet

I've been working on a new preset to recommend as "my first decent espresso" to people receiving an espresso machine from us.

Previously, I used to recommend the "best for milky drinks" program, because that's what I generally use every day. Rao argued that this was a difficult recipe to get your grind calibrated for, and the discussions here on Diaspora have generally agreed. It's a great recipe, but it takes careful grind and dose adjustments to make it work well.

We often find (on the Diaspora forum) that new users have too coarse a grind, and cannot reach much pressure. Or their shots channel badly. It'd be nice to have an easier first espresso.

So.... this new "gentle and sweet" recipe is my attempt at a "first time user" friendly espresso. I have been pulling it myself as my morning beverage these past 2 weeks, as it's a great shot to pull when you're only semi-coherent. It does not demand excellent puck prep. Flow rates between 0.5 ml/s to 2.5 ml/s out of this recipe, all taste good.

Here's my description for this preset:

"This is a very easy espresso to successfully make and is suggested if you are having difficulty making good drinks. The pressure rises to only 6 bar and then slowly descends to 4 bar. The resulting espresso should be free of channeling, have low acidity and quite pleasant to drink straight or with milk."

A few people on the Diaspora forum have already tried this and reported good results.

This new recipe "gentle and sweet" is now available in the DE1+ app. Use Settings->App Update to get it. Exit the app and relaunch.

-john