Quick Mill Carola EVO – Review & Photos

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narwhal

Postby narwhal » Dec 30, 2018, 7:52 pm

Intro

A lot has been said about the original Quick Mill Carola in this review from 2015: Quick Mill Carola - Review. Thank you for this great info in this thread!

Now there is an updated Carola - the Carola EVO. I recently purchased one from Chris' Coffee and thought I would pay back the community by posting my experience and photos. There's not a ton of info out there about this machine, so hopefully this helps.

As I learn more and get into a routine with the machine, I will try to post any updates.

Disclaimer: I'm new to semi-automatics, so I don't have a ton of espresso experience, but I at least tried to provide a lot of photos. Oh and please ignore my current grinder situation!

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Overview

If you are reading this, you perhaps know that the Carola is an unusual machine because it has no steam or hot water wands. So, it's basically the brew half of a dual boiler.

But for less than $1k you get the high-end functionality and look of the E61 brew group, along with features like a PID, pressure gage, and easily-accessed pump pressure adjustment valve.

So, if you are on a limited budget or just want a great machine for pulling shots, it's a unique and appealing option. The Carola EVO is simple, high quality, and fun to experiment with. So far, I love it!


Purchase Experience

In the USA I believe Chris' Coffee is the only importer/seller of the Carola. I found them to be helpful, knowledgeable, and quick with my order.

As documented in prior reviews, the machine arrives very well-packaged in a double box. I was first concerned that the inner box had been opened and resealed, but it turns out that Chris' Coffe tests and inspects each unit before sending to the end customer. Nice.


Initial Impressions

My unit arrived without a scratch, and I was immediately impressed by its heft and good looks. Build quality was better than expected. It's solid and everything fits together well.

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Updates in the EVO version

Pressure Adjustment:
The biggest functional update to the Carola EVO seems to be the externally-accessible pump presure adjustment valve (a.k.a. over pressure valve or expansion valve.) The original Carola required you to open up the whole machine and adjust this valve with two wrenches. Now you just lift the drip tray and turn the screw. This was a really nice surprise!

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I believe the top panel was redesigned to accommodate the new pressure valve location. This may make is a bit trickier to fully-disassemble the machine and access the area above the boiler. Worth it.

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The machine arrived adjusted to exactly 9 bar, probably because Chris' Coffee dialed it in during testing. The new valve location allowed me to easily adjust the machine up from 9 to 10 bar.

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Cup Warmer:
The EVO now has a really nice cup warmer fence, where none existed before. Also, unlike other photos I've seen, my machine's cup warmer vents are towards the front, which makes more sense for heat flow.

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Drip Tray:
The cutout pattern on the drip tray is now more intricate and interesting on the EVO.

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Labeling:
The logos and labels have been updated to the style of Quick Mill's higher-end machines. They are not decals... maybe laser etched?

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Switch:
The switch is now a 3-way toggle (used to be 2-way) which has modes for off (0,) pump on (1,) and pump/heater on (2.)

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Minor Changes:
Some other minor differences I noticed are a slightly different plastic handle on the E61 lever and a different kind of insulation on the boiler. I'm sure there's a few things I missed!


Under the hood

Under the hood, most of the components appear to be the same as the original Carola.

Drip Tray:
The drip tray is pretty nice and seems to be sufficiently big in footprint and volume. I don't think the size has changed, but unlike other reviewers, I never get water splashing off the front. One nice feature is that the tray can lift or slide straight out without having to tip it.

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Noise Considerations:
The vibration pump is mounted on rubber flanges to reduce noise (black tab in the lower left of this photo.)

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It also still has a Pulser (the white plastic disc near the bottom in the next photo) which I believe is a fairly unique and effective feature for further noise reduction. Overall, it's quieter than I expected.

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The buzzer looks a bit different on the EVO, but it's still annoyingly loud. I put some tape over it, which brought it down to a nice subtle volume. It beeps once when the machine turns on and repeatedly when water is low.

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Water Sensor:
The low water sensor is non-contact and engages at a logical water level (shown in next photo.) I tested this because I read a review where somebody had to adjust this.

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Wiring:
Wiring is relatively tidy and routed with zip ties. Wire gauge seems reasonably thick.

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Tubing:
The copper and plastic tubing seems generally well-done. There are a few spots where the tube paths aren't quite perfectly planned (e.g. the lower E61 tube wedges against the top of the boiler) or have crimped a bit where they have been bent. Some of the plastic hoses are also routed such that they rest on a hot copper tube, although this is likely not an issue at these temperatures.

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E61:
I have read that many substandard "E61" variants exist in the world, but this E61 seems to be the real deal with heavy chromed brass, preinfusion, thermosiphon, etc. Regarding the thermosiphon, note the two vertically spaced copper tubes attached to the group, as seen in the previous photo. The group head and portafilter definitely get really hot while the machine idles.

PID:
The Gicar PID has not changed from the original Carola, which is probably the EVO's biggest missed opportunity. I could see the dip switches scaring off potential customers, and the location behind a back panel is pretty inconvenient. Adding insult to injury, the switches are upside-down and backwards. But I think Gicar is a good brand, so hopefully it will prove to be reliable.

https://www.gicarsrl.com/wp-content/uploads/2015/10/Temperature-controls-and-probes.pdf

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Performance & Operation

Pulling Shots:
So far, I have found this machine to be quite forgiving. Within a couple days, I went from never having used a semi-automatic to consistently achieving what seems to be pretty good results despite being self-taught and having a cheap grinder.

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Warm up:
The boiler reaches temperature in about 10 minutes, at which time you can theoretically pull a shot. Full warm-up of the group head seems to take more like 20-30 minutes.

The PID engages the heater in roughly a 1sec on / 1sec off cycle while getting up to temperature and does a short pulse every couple seconds when maintaining temperature. I'm not sure if that's typical or not, but I imagined it would heat up more aggressively.

Power Usage:
I have the machine plugged into a Wemo Mini (for remote control and scheduling) and into a Kill-a-Watt meter (for measuring the electricity usage.) The meter tells me that the machine uses about 750 Watts when the heating element pulses on, so the machine's overall 850 Watt peak rating is a reasonably conservative claim.

The meter also tells me that if I left the machine on 24/7 for a year under mixed use, it would cost about $100 in electricity. I plan to have the machine on for a couple hours per day, so my energy costs will only be like $10 per year. And in the winter, that E61 is like a second furnace ha!

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Portafilters:
The machine comes with the same single and double spouted portafilters mentioned in previous reviews. The single is nice to have as a dedicated backflush portafilter. The baskets are ridgeless.

I also got this bottomless portafilter, which works great. It has a ridged triple basket of ok quality but seems to retain a ridgeless just fine (I plan to get a 22g ridgeless VST basket for it.) https://www.amazon.com/dp/B06ZZ24BH2/

Chris's Coffee also recommends the Rancilio bottomless portafilter on their website as a compatible (and likely higher quality) option.
https://www.chriscoffee.com/e61-group-bottomless-portafilter-p/rrbpf.htm

I was pleasantly surprised that locking the portafilter into the machine is a 1 hand operation. The machine is "small" but dense and stays firmly planted on my countertop partly thanks to the rubber feet. The whole machine does flex a bit though.

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Preinfusion:
As you probably know, E61's have built-in mechanical preinfusion via a flow restricting orifice and extra chamber that needs to fill before the pressure can ramp up. This seems to work quite well for even extraction.

Additionally, there is a point in the Carola EVO's lever throw where the valve between the group head and the boiler is open but the pump is not yet engaged. If you pause at this position, the coffee puck is exposed to water at boiler pressure (seems to be about 2-3 bar) for as long as you want. This gives you additional control over preinfusion (or this may be considered pre-wetting.)

Personally this seems to be unnecessary, and the lost water volume seems to result in a longer time to ramp up to pressure when you do engage the pump. But, hey, it's another fun thing to tinker with, and I have read that not all E61 machines allow you to do easily finesse the lever in this way.


Drawbacks

So far I'm generally quite happy with the Carola EVO, but it does have some (mostly minor) drawbacks and annoyances.

Drip tray:
While the size is perfectly functional for catching water, at 90mm deep from the front to the E61 exhaust valve, it is too small for most scales.

Assembly:
While overall the machine seems well-assembled, I was a bit disappointed that my E61 group was installed ever-so-slightly askew. Luckily, it wasn't installed overly-tight, so I could just carefully nudge it without messing with any bolts.

And my machine, while pristine on the outside, had some sooty residue on the inside of the panels that came off with an alcohol wipe.

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PID Temperature Adjustment:
This is the big one! The PID is about as basic as it gets. It lacks a front panel display/buttons and, as far as I can tell, any control over the temperature offset. As mentioned before, the hidden dip switch controls are inconvenient to say the least.

But it probably knocks about $100 off the price compared to a more complex PID installation, and few machines at this price point have a PID at all. And I keep telling myself that even some Rocket machines have a temporary plug-in PID control module. "it's just like a Rocket, it's just like a Rocket, it's just..." ...ok maybe not quite.

So, if you mainly want a PID for the sake of consistency and convenience, then the Carola's PID is probably all you need. And while a temperature readout is cool, the heater light makes it fairly clear when the boiler has reached the target temperature. But if you plan to constantly tinker with the temperature setting, then the Carola's PID could get annoying pretty quickly.

Regarding temperature offset, I had the PID set to 203F and ran a bunch of water into a insulated cup that I pre-heated with boiling water. The water in the cup measured 194F. I don't totally know the implications of this quick test, since some temperature would be lost as the water dripped through the air into the cup. But I do think it would be nice to have some control over the PID offset. I may ask Chris' about this and potentially run a better test with a thermocouple embedded in the basket.

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In the end, I'm primarily just happy that I'll never have to go down the rabbit hole of temperature surfing or heat exchanger flushing. But I do still wish the PID had all the bells and whistles.

Low Water Alarm:
When the low water alarm is triggered, the pump stops until you refill the reservoir, even if you are in the middle of pulling a shot. I'm not sure if other machines do this, but it is definitely an annoying safety "feature."

Steam / Hot Water Wand:
And the big drawback you accept with this machine is the lack of a steam and hot water wand. It's up to you how important this is, so I won't go deeper.


Other Considerations

Descaling:
Chris' recommends against descaling by the end-user and thus does not provide any guidance for DIY descaling. But they do provide a pretty nice cleaning kit for backflushing. While I admittedly have no experience with this, I'm guessing that the machine will eventually need descaling, and I really don't like the idea of lugging it into a shop for this.

For now, I'm following this water recipe, which achieves hardness with magnesium instead of calcium, and my understanding is that it will cause little to no scaling. https://www.wholelattelove.com/blog/brew_sca_approved_water/

Materials:
The boiler is brass coated with TEA coating. I looked into this bit, and it seems to be a real thing, including NSF certification. However, I think we all would prefer a stainless boiler for total piece of mind from a health perspective, and many of the Quick Mill machines are starting to go this route.

With the Carola, your water does touch plastic, but I don't believe any hot water touches plastic. The reservoir seems to be pretty nice thick plastic, but I didn't see any mentions of whether it's BPA-free etc.

Cup Clearance:
The Carola EVO's cup clearance works well for me. It measures about 80mm from the drip tray to the bottom of a spouted portafilter and about 125mm from the drip tray to the bottom of a bottomless portafilter. My rather large 5 ounce Sweese 4601 cups fit under either.

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Brand

Quick Mill is not exactly a household name among entry level shoppers, and the Carola is something you sort of have to discover after wading through a sea of Silvias, Brevilles, etc. But after more shopping around, I realized that Quick Mill seems to be a well-established and respected brand whose product line reaches all the way into the commercial realm. It also comes with a 2 year warranty (1 from Quick Mill and 1 from Chris') which I am happy with.


In Summary

Quick Mill seemed to do a great job of committing all of this machine's value towards providing a high-end experience for pulling quality shots. As important, they showed restraint from adding anything that does not directly contribute to this goal. My main critique is that they maybe they stopped a bit too short when it came to the PID spec.

In the end, it's a unique machine that designed for the pure espresso/americano enthusiast, since it is essentially the brewing half of a dual boiler machine. For my budget and priorities, it struck a great balance of price, features, and user-experience. So far, I'm quite pleased with the machine overall, and I will try to provide updates as they come.
★ Helpful

RyanJE

Postby RyanJE » Dec 30, 2018, 8:26 pm

Too bad they didn't just add a real PID... I thought that's what they did on most EVO versions....

That would be a killer machine at the 900-1000 price point for espresso only....
I drink two shots before I drink two shots, then I drink two more....

narwhal

Postby narwhal » Dec 30, 2018, 9:08 pm

Agreed. I would have paid more for it. I'll likely end up getting Eric's E61 thermometer or similar, which will at least help me understand what's happening at the puck.

ChileBean

Postby ChileBean » Dec 31, 2018, 9:17 am

Narwal,

This is an excellent review! Well done. I know it takes a certain amount of courage to unpack your perfectly new machine and then proceed to take it apart. But your many pictures really are very helpful, and you have done an excellent job in writing your review. I am sure it will serve the community well for many years.

From what I can see, this machine is almost identical to the one I reviewed in 2005. I looked at your pictures carefully and while you may have missed a difference between your machine and mine, I did not spot it.

You have prompted me to provide an update to my review, which I will get to later today. I have used my Carola almost every day since I got it. I have experienced only two problems.

1- The low water level sensor started to trip even with a full reservoir. I called Chris Coffee and the tech talked me through the process of readjusting it. That part is a bit of a pain, and I experienced some strangeness during the process which I will write about in more detail when I update my review. But in a nutshell, you take the black sensor out of the machine, open it, adjust the small trim pot a little bit (maybe 1/8 of a turn), put the sensor back together, reinstall it in the machine, test it, and repeat if necessary.

2- I put the clear plastic reservoir in the dishwasher once and it distorted the shape of the container (my bad). DON'T PUT THE RESERVOIR IN A DISHWASHER.

Over the years I have had the opportunity to make some great espresso on some very $$$$ machines. TBH, I could tell no difference between the espresso from those machines and from my QM. Yes, the big machines do better at consistency when running shot after shot after shot - not what I do. Yes, the PID and boiler are more accurate - not what I have found to cause the largest variations in espresso results. Without a doubt, the greatest determining factor in whether you will have a good shot of espresso, once you have invested in some sort of "real" espresso machine is the beans. If they aren't fresh, forgetaboutit. If they do not produce an espresso you like, forgetaboutit. No amount of fiddling and no amount of money spent on a machine will produce a cup of espresso you enjoy.

Brad

narwhal

Postby narwhal » Jan 06, 2019, 8:24 pm

Quick Update:

PID:
Chris' Coffee says that there is indeed an offset built into the PID, although it is not adjustable.

Also, I'm getting used to the dip switch control for temperature. I just leave the back panel open and lean over the machine with a big wooden toothpick to flip the switches... not a luxury experience but doable.

Also, I noticed that the previous review that the temperature range was stated to go up to 205F. The manual now lists settings ranging from 195-209F.

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Descaling:

Chris' Coffee also backed off a bit from the Carola manual's strong warnings against descaling. It sounds like they are happy to provide guidance to customers on a case-by-case basis.

Performance:
I now have upgraded to a Eureka Mignon Specialita grinder. What everybody says about the grinder being critical is 100% true. I'm glad I "saved money" by going with the Carola and put it into a proper grinder. Shots are honestly not any easier to pull than they were with my Capresso Infinity, but the taste is much smoother and stronger at the same time. Blonding seems to happen later, and the cup has less sediment.

Strangely, the crema I now get seems to be lower in volume but higher in quality (finer bubbles & better mouthfeel.) Maybe somebody out there has some knowledge or advice about whether or not this makes sense when moving from a cheap conical to a mid-level flat burr?

Anyways, the grinder and machine really seem go well together, both in terms of function and looks - even on top of an Amazon Basics pet food mat haha!

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mlunsford27

Postby mlunsford27 » Jan 07, 2019, 6:18 am

I'm considering this machine in the future. Thanks for the detailed review, seems like a great value. Couple questions:

Do you know if it is possible to change the PID parameters to make heatup more aggressive?

Do all PID controllers for espresso machine boilers cycle the heating element on 1 second then off 1 second like you mentioned? Or is this unique to the Carola and what is the purpose do you think of doing this? I know you mentioned that you are not sure why it behaves this way but wanted to see if anyone else on this looking at this post has an idea.

Thanks

Davi-L

Postby Davi-L » Jan 07, 2019, 8:39 am

Greetings,
I have the QM Alexia from 5 years ago. I ordered with a PID mounted on the front panel. It works well.
What you have is not a PID but rather an electronic thermostat. Cheaper to put in the machine.

I can't see all the features of the thermostat, and there maybe an adjustment for aggressive heating. I don't think so.
I've tried to heat my Alexia faster by bypassing the PID but it just takes so much time to heat up the mass of metal that only a few seconds may be saved.
My machine starts off with full heater power, and when it gets to 10 degrees C of the set point, it starts to pulse the power so as to not overshoot the set point. That's how PIDs work and they do it very very well. The Watlow PID can be adjusted for this heater on/heater off time base from any number of seconds to totally variable. That variable time base causes the lights in the old house to dim slightly with each rapid pulse. Rather annoying. At one secornd, it is less noticeable. In my new home the 200 amp service seems to absorb most of this pulsation. No electrician has explained it to me yet.
You could upgrade to a real PID, Watlow is good, Fuji is good too. You would need a solid state relay to power the heating element. But I think your thermostat will do the job just fine. A pain to adjust I admit, and I only adjust mine summer to winter as the kitchen gets hotter in the summers. I don't have AC for the house.
Enjoy your espresso, I'm going for one right now.
Dave

mlunsford27

Postby mlunsford27 » Jan 09, 2019, 8:05 am

Thanks for the recommendations on PID controllers. The website does say that the Carola has a PID, so I think that it does but just not a digital display. Therefore, it will still control the temperature without overshooting and then dropping down in cycles causing deadband. In this case it just appears to be a pain to change the temperature.

hbn

Postby hbn » Jan 09, 2019, 10:42 am

Awesome! Thank you for the in depth review and pictures. Quick Mill is/was one of the brands i was considering

Do you have any other models/brands you have used personally that you can compare it to?

narwhal

Postby narwhal » Jan 09, 2019, 11:59 pm

The only other machines I've used personally are Jura superautomatics, so I won't pretend to have a valid viewpoint on comparatives.

My decision process was this:
1. A few friends have gaggia classics. $400 seems insane compared to my french press, but I thought maybe I can get a refurbished one! I tried to buy one actually, but it went out of stock right before I hit the buy button.
2. Crossed the GC off the list due to aluminum boiler. Interested in a Silvia. A friend has one, and temperature surfing seems lame after spending $700, but hey I could always add a PID for $200 down the road.
3. Well dang, then I'm at the same price as a Carola, and I don't do milk drinks anyways.
4. After a brief daydream about the ECM Classkika PID, I bought the Carola. Crap now i should probably get a grinder.
5. In so deep that the Specialita grinder somehow now seemed like a great value, and I managed to get a deal on one. What happened to me?!