Lelit MaraX

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Bluenoser
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#1: Post by Bluenoser » Oct 23, 2019, 10:42 am

Looks like Lelit is introducing an HX that addresses the usability of HX machines in the area of brew water temperature control. However I only see a low, med, high setting which would mean nothing to me. I couldn't understand how their control system works.


Anyone have any clearer explanations?

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skansen

#2: Post by skansen » Oct 23, 2019, 12:15 pm

Bluenoser wrote:However I only see a low, med, high setting which would mean nothing to me. I couldn't understand how their control system works.
It's PID controller with two probes made by Gicar. Electronics will give priority for the coffee temperature. User can choose one of three preset temperatures (warm, hot or extra hot).

Bluenoser
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#3: Post by Bluenoser » Oct 23, 2019, 12:27 pm

In an HX, I assume one probe would go in steam boiler.. not sure where other probe would go.. near top of thermosiphon?.. If so, wonder what mechanism would control thermosiphon temperature? Do they slow down the circulation to drop temp? HX is pretty simple so not sure how they are controlling the brew water any better.

I think it said that the machine still requires flushes.. again.. not sure how that 2nd probe would actually control anything. Only thing I can think of is that if 2nd probe (in TS?) found brew water cool then Gicar would raise the steam boiler temp ... but that has to have a huge lag in getting from steam boiler change to TS temp change.. And if there's an E61 on it, well, that has huge effect on final output brew water temp.

Doesn't sound like you'd have any manual control over steam boiler and ultimately how much steam power produced. Looks like they've been working on it for a few years, so must have lots of thought in it.

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another_jim
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#4: Post by another_jim » Oct 23, 2019, 4:12 pm

I've been reviewing a beta version of the machine for the last three months. The claims are mostly correct:

This is a very basic, small boiler, HX, vibe pump E61 box with specs mostly identical to the base Mara. What's different are the controls. There is a PID in the steam boiler which switches between two set points, one at around 2 bar, one at 1 bar. The setpoint chosen depends on the the temperature of the water returning from the thermosyphon into the boiler. This approximates the group temperature, and since this is a massive E61 group, it is also close to the same as the shot temperature, whether the boiler is at 2 bar, 1 bar, or somewhere in between.

The result is that you can make a no flush shot that goes as long as you like without worrying about temperature. But you aren't going to get a whole lot of precision either, roughly 90 to 92 at the low setting, 94 to 96 at the high, and 92 to 94 for the middle setting. This is about the same as you can get with Eric's group head thermometer and a flushing regime. Personally, I much preferred using this control to having to do it myself. But I've been spoiled with the Strega and Bianca, which are no fuss machines when it comes to managing temperature.

The three position switch is an honest control, since the nature of group makes anything more precise than about a 2C range on shot temperature impossible. For instance, on dual boiler E61s, the precise adjustablilty of the brew boiler is to some extent an illusion, since the shot temperature will also vary up or down in a two degree envelope or so. A three position switch would work just as well on an E61 DB.

On a historical note: Over the last fifty years, many companies have patented thermosyphon based active controls; and none, as far as I know, have made it into production. They've all been too finicky. Us hobbyists also have not come up with anything stable. What Lelit is doing, switching the boiler between a low and high setting based on the thermosyphon return, may sound really simple, but that is very good engineering in my book, a simple, stable solution to a fairly tricky controls problem.

In addition, Lelit has tweaked the group jet and and expansion valves so that you can use very fine grinds on this machine without choking it. It isn't quite as versatile as having a needle valve kit installed, but it does get close. Note: I have not used the regular Mara, so I don't know if that has the same fine grind tweaks. I am instead comparing it to older E61 boxes I've used.

Steaming is trippy, since you get close to commercial speed performance when the steam is up at 2 bar; and rockaby-baby-HX performance when it's down at 1 bar. There's also an initial warm up accelerator in the controls (similar to the Bianca), so if you catch it just right after start up, you'll see the steam up at 2.75 bar (!), and get a real rush on your cappa. (or a near heart attack the first time you see it, when you expect to get blown across room -- I'm sure the updated manual will clearly note this tweak)

I don't know what the price premium is on this version of the HX, but in terms of stability and no fuss, it gets you to about the same place as a double boiler E61, in a fairly compact, counter space friendly package.

I enjoyed using it. But people should note, this is not a "high tech" machine; it is a basic espresso machine that has been polished so it works like a simple tool, making no fuss shots. It's not a machine for people who want a lot of precise adjustments, or a lot of during-the-shot control.
Jim Schulman
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pnassmac

#5: Post by pnassmac » replying to another_jim » Oct 23, 2019, 4:44 pm

Hi Jim,

In comparison to a small dual boiler, like the Profitec Pro 300, and its intended use, how would you compare the two in real-world use?

Thanks.

cskorton

#6: Post by cskorton » Oct 23, 2019, 8:04 pm

Here's a short video on it:
Most importantly, does anyone know if it's compatible with Lelit's Pressure Profiling Paddle found on the Bianca?

Bluenoser
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#7: Post by Bluenoser » Oct 23, 2019, 8:08 pm

another_jim wrote:I've been reviewing a beta version of the machine for the last three months. The claims are mostly correct:
.
Jim.. thanks for taking the time to detail the design. I've been struggling with a Profitec Pro 500 PID for about 18 mo. And finally had to get a SCACE and Erics thermometer to really understand its thermal characteristics.. I will say in the Profitec design, I am really, really disappointed that it cannot make back-back espresso-based drinks in, what I consider, a reasonable time. I'm wondering how much they actually tested this current design.

I would have to assume that the Lelit machine doesn't have much or any restrictor in the TS loop or else the lag between sensing and change would take too long. Maybe that is where the effort in engineering is.. in finding that balance in the TS loop ..

I would fully agree that in any E61, HX machine, that a 2 degree swing is more than stable enough. I'm not sure if that is enough range for the higher experienced people who use a wide range of roasts level.. but certainly better than I've been able to get after over a year. It would be interesting to see how it fairs in back-to-back milk-based drinks, mixed with pure espressos.. Sounds like it would be much more productive for successive shots.

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slybarman

#8: Post by slybarman » Oct 23, 2019, 8:28 pm

another_jim wrote: so if you catch it just right after start up, you'll see the steam up at 2.75 bar (!), and get a real rush on your cappa. (or a near heart attack the first time you see it, when you expect to get blown across room .
LOL'd

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another_jim
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#9: Post by another_jim » Oct 23, 2019, 8:38 pm

cskorton wrote:Here's a short video on it:

video

Most importantly, does anyone know if it's compatible with Lelit's Pressure Profiling Paddle found on the Bianca?
The video is good, and repeats the points (and polite obfuscations) that I got from Mauro during the testing. Basically, what they've done to the temperature is an open book. But the tweaks that make this a machine that can handle really fine grinds (On 15 grams of Turkish grind you get the first drops in about 15 seconds), I got the same polite disquisition on hydraulic adjustments that you see in the video.

My point in repeating this hydraulic disquisition is that group will work with the needle valve mod, but the machine has already been tweaked for fine grinds, and so has a lot less need of it than most machines.
Jim Schulman

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another_jim
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#10: Post by another_jim » Oct 23, 2019, 10:17 pm

Bluenoser wrote:I've been struggling with a Profitec Pro 500 PID for about 18 mo .... it cannot make back-back espresso-based drinks in, what I consider, a reasonable time. ... It would be interesting to see how it {ed: the Mara} fairs in back-to-back milk-based drinks, mixed with pure espressos.. Sounds like it would be much more productive for successive shots.
Here's an the relevent excerpt from my notes:
MaraX notes wrote:In the middle temperature position, shots after a long idle run at 93C. If one pulls at 90 seconds to 2 minute intervals, the temperature settles at 92C to 92.5C. If one pulls at 1 minute intervals, the thermosyphon crashes and the group falls to 90C. It will then overshoot to 95C in the recovery. So, provided shots are pulled at 90 second or slower intervals, the temperature is stable within 1C without any flushing or bother. This is as good or perhaps even a hair better than double boiler E61s.
I won't post a detailed review of every aspect of the MaraX, since even well built E61 boxes are not news, but I will put together an article on the thermosyphon based control, which is news. The Beta machine I got was equipped with monitors on the temp sensors, so I'll be able to post on the machine's dynamics. I didn't do the intense use test that Dave wants, but I'll try to do it before I post.
Jim Schulman