# HX or DB?



## Montana (Jan 3, 2013)

Hello, right I currently have a classic but looking to upgrade now. The question is HX or DB, I only make one espresso at a time and drink it as a americano with just a tiny amount of milk, which is getting less and less as my coffee gets better. So will I notice a advantage buying a DB machine over a HX one. My routine is, warm the machine up go 30 mins, then a 6 second cooling flush and I'm good to go. The reason I ask is there seems to be some really nice HX machines coming up second hand at around £700-800 which I'm sure would be a nice step up from the classic.

Thanks Rich.


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## DavecUK (Aug 6, 2013)

If you can afford it get a Dual boiler of course....better to buy mid range dual boiler than bottom end.


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## Daren (Jan 16, 2012)

Will you be pairing it with that bling SJ?


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## Montana (Jan 3, 2013)

I will Daren!! I keep looking at a La Spaziale S1 mini but it's twice the price of a nice used HX machine. Guess I'll just wait till a nice used DB comes up that I like.


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## MediumRoastSteam (Jul 7, 2015)

Hi Montana. You say you drink Americanos with just a tiny bit of milk. I take you don't steam any milk?


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## Montana (Jan 3, 2013)

No I don't steam any milk, which is kind of why I'm unsure I'll get much of a advantage from getting a DB.


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## Daren (Jan 16, 2012)

Have you considered a lever?


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## marcuswar (Aug 19, 2013)

If you don't steam milk then I would think the DB is the better route as you'd get much better control of brew temperature (especially if it was a PID model) and could turn off the steam boiler to save energy. The HX would be harder to use as you'd have to master the flushing technique to get the brew temperature correct. My understanding is that a HX simply allows you to steam at the same time as pulling a shot using only a single boiler hence cheaper than a DB. The only possible slight advantage of HX over a DB that I can think of is that the brew water is always taken fresh from the tank (or mains feed) through the HX where as the water has been sitting in the boiler of a DB since last time it was used.


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## MediumRoastSteam (Jul 7, 2015)

If you don't steam milk, have you considered the Bezzera Unica? It is a single boiler dual use machine with PID and an e61 group. Also will be much easier to descale.


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## cold war kid (Mar 12, 2010)

pessutojr said:


> If you don't steam milk, have you considered the Bezzera Unica? It is a single boiler dual use machine with PID and an e61 group. Also will be much easier to descale.


Beat me to it.

Great temp stability with the e61 and PID and still able to steam when guests come round. It's cheaper than most HX's and all double boilers as well.


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## Montana (Jan 3, 2013)

Daren a lever would be nice but will need to come with training!! Maybe Coffeechap will have something for sale soon.


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## Daren (Jan 16, 2012)

@coffeechap is a bad man who brings joy


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## coffeechap (Apr 5, 2012)

Coffee chap may well!


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## Tewdric (Apr 20, 2014)

Being a bit controversial, If you don't drink espresso and don't steam milk you would probably get as good or better a long cup from a chemex or aeropress.

If you were to invest in a better grinder, instead of a better machine, you may enjoy the sort of coffee you like more than diluting espresso shots with water.

Having said that the absolutely magical espresso that a lever coupled with a good grinder can produce will convince you that you love espresso!


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## Rhys (Dec 21, 2014)

Tewdric said:


> Being a bit controversial, If you don't drink espresso and don't steam milk you would probably get as good or better a long cup from a chemex or aeropress.
> 
> If you were to invest in a better grinder, instead of a better machine, you may enjoy the sort of coffee you like more than diluting espresso shots with water.
> 
> Having said that the absolutely magical espresso that a lever coupled with a good grinder can produce will convince you that you love espresso!


+1 on this..

Levers aren't that hard to use, if I can use one then anyone can. La Pavoni's are great for pulling a couple of shots before they get too hot and are mechanically simple, don't need backflushig (you can't anyway lol). I get great satisfaction from using mine and to think you pay thousands of pounds for a pressure profiling machine (Vesuvius etc.) which just copy what a lever does naturally







they are also very easy to descale, and have a small footprint. Pour-overs are good as well, and good for SO beans.


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## Rdl81 (Sep 8, 2014)

Sorry to hi jack the thread I have a cherub but I only really drink espresso as I use my v60 or areopress for long drinks. If I was to upgrade would lever be way to go? Anything in particular?


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## 4085 (Nov 23, 2012)

marcuswar said:


> If you don't steam milk then I would think the DB is the better route as you'd get much better control of brew temperature (especially if it was a PID model) and could turn off the steam boiler to save energy. The HX would be harder to use as you'd have to master the flushing technique to get the brew temperature correct. My understanding is that a HX simply allows you to steam at the same time as pulling a shot using only a single boiler hence cheaper than a DB. The only possible slight advantage of HX over a DB that I can think of is that the brew water is always taken fresh from the tank (or mains feed) through the HX where as the water has been sitting in the boiler of a DB since last time it was used.


But a lot of modern HX machines do not need the cooling flush as they have thermosyphons on them.......I have one on mine and I simply draw15 mms of water off when I unlock the pf and before I grind to make sure everything kick starts


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## jeebsy (May 5, 2013)

dfk41 said:


> But a lot of modern HX machines do not need the cooling flush as they have thermosyphons on them.......I have one on mine and I simply draw15 mms of water off when I unlock the pf and before I grind to make sure everything kick starts


Would be interesting to see what's going on a the group with an E61 thermometer


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## 4085 (Nov 23, 2012)

I bought an Erics but never used it. There is simply no need to. You know what a thermosyphon does. Providing it does not stall then it runs continuously. The Nota is a very stable machine using the same technology as its fully fledged 2 and 3 group family


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## marcuswar (Aug 19, 2013)

I thought the thermosyphon was part of the E61 design? My Isomac Tea has is a HX with a E61 brew head but it still needs differing lengths of cooling or warming flushes to get the correct temperature dependant upon how long it's been left on. I know because I have an Eric thermometer on it and can see how it reacts differently. It may be that dfk41 has a machine where the flow of the thermosyphon has been tuned for his machine using restricted in its flow? Mine idles at about 100C after 45mins warmup. I could probably lower this slightly by lowering the pressurestat but that would mean I'd have lower steam pressure as well.

I think part of the reason for the flush on a HX is to purge the superheated brew water that's been sitting in the HX pipe. Which in turn then overheats the brewhead so requiring a longer flush to cool it back down with fresh water passing through the HX.


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## Dylan (Dec 5, 2011)

marcuswar said:


> I thought the thermosyphon was part of the E61 design? My Isomac Tea has is a HX with a E61 brew head but it still needs differing lengths of cooling or warming flushes to get the correct temperature dependant upon how long it's been left on. I know because I have an Eric thermometer on it and can see how it reacts differently. It may be that dfk41 has a machine where the flow of the thermosyphon has been tuned for his machine using restricted in its flow? Mine idles at about 100C after 45mins warmup. I could probably lower this slightly by lowering the pressurestat but that would mean I'd have lower steam pressure as well.
> 
> I think part of the reason for the flush on a HX is to purge the superheated brew water that's been sitting in the HX pipe. Which in turn then overheats the brewhead so requiring a longer flush to cool it back down with fresh water passing through the HX.


There are multiple machines that employ systems to eliminate the cooling flush. There was a whole thread on it before that came from an article on Londinium which I think was talking about the Fracino models.


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## 4085 (Nov 23, 2012)

The Londinium does not use an E61....


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## Dylan (Dec 5, 2011)

dfk41 said:


> The Londinium does not use an E61....


That's why he was talking about the Fracino models


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## jeebsy (May 5, 2013)

dfk41 said:


> The Londinium does not use an E61....


Yeah it uses the Bosco group


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## marcuswar (Aug 19, 2013)

Thanks for the replies guys, I'm obviously behind the times







So other than flow restrictor in the HX what other technology do these newer machines use to keep a stable temperature?


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## Dylan (Dec 5, 2011)

Here is the Londinium article

http://londiniumespresso.com/blog/e61-machines-with-heat-exchangers-that-dont-need-a-cooling-flush

Rocket machines also have some type of system for regulating the temp, and the manual of my VBM says the same although it doesn't appear to be true for the machine I have (maybe it's age)


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## DavecUK (Aug 6, 2013)

Dylan said:


> Here is the Londinium article
> 
> http://londiniumespresso.com/blog/e61-machines-with-heat-exchangers-that-dont-need-a-cooling-flush
> 
> Rocket machines also have some type of system for regulating the temp, and the manual of my VBM says the same although it doesn't appear to be true for the machine I have (maybe it's age)


Ah I love to see the laws of physics broken I really do by Fracino, Vibiemme and Rocket.....smelling huge amounts of bullshit. An HX system any HX system is a compromise...to make it otherwise would require so much complex technology that it would be far cheaper and easier to build a dual boiler system.


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## Dylan (Dec 5, 2011)

DavecUK said:


> Ah I love to see the laws of physics broken I really do by Fracino, Vibiemme and Rocket.....smelling huge amounts of bullshit. An HX system any HX system is a compromise...to make it otherwise would require so much complex technology that it would be far cheaper and easier to build a dual boiler system.


Surely it just requires not injecting superheated water into the group? Pulling some cold water in too sounds like a perfectly reasonable proposition?


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## jeebsy (May 5, 2013)

Then you need a mixing valve of some sort, how cold is your cold water, at what point does your water get so hot it needs mixed etc etc


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## Dylan (Dec 5, 2011)

jeebsy said:


> Then you need a mixing valve of some sort, how cold is your cold water, at what point does your water get so hot it needs mixed etc etc


The water going into the group isn't the right temperature in any case, the mass of the group levels out the water temp, so you only need to mix the water to the right ball park temp. No different to flushing without any additional systems.


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## Dylan (Dec 5, 2011)

A thread where someone tested their machine after idling an hour: http://coffeeforums.co.uk/showthread.php?22742-Anyone-still-doing-a-cooling-flush-on-a-Fracino-machine


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## jeebsy (May 5, 2013)

The water going into the group is the right temp. It only becomes 'wrong' if its left to overheat


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## Dylan (Dec 5, 2011)

The water going into the group is not 'stable' the stability is achieved via the thermal mass of the group.


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## jeebsy (May 5, 2013)

What determines how hot the group is?


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## Dylan (Dec 5, 2011)

Are you trying to say that the superheated water cycling from the boiler is the same temp as the group?


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## insatiableOne (Jul 29, 2015)

Rhys said:


> +1 on this..
> 
> Levers aren't that hard to use, if I can use one then anyone can. La Pavoni's are great for pulling a couple of shots before they get too hot and are mechanically simple, don't need backflushig (you can't anyway lol). I get great satisfaction from using mine and to think you pay thousands of pounds for a pressure profiling machine (Vesuvius etc.) which just copy what a lever does naturally
> 
> ...


I agree with the lever part, being the way to go.

Just wish people would stop spreading fodder of the La Pavoni's can only make a couple of shots → then overheat.

Sure if your using 75 year old Europiccola technology, or even the pre-millenium.



> *While many (lower priced) pump espresso machines do not actually have enough power to produce a hot cup of coffee, the La Pavoni dilemma was that it produces too much heat. This is one reason the La Pavoni lever machine is a steaming gem, cup after cup of cappuccino can be produced with little or no recover time. This heat problem was barely noticeable when making 3-4 cups, but if more drinks need to be prepared then a sufficient "crema" would be harder to achieve. (ed note: in our testing the first shot is the best; it is a slow downgrade after that point due to heat damage).*
> 
> 
> 
> ...


So any La Pavoni made after 1999 is good to go.

Their new models can be left on all day no issues ever. One here or there might need the boiler adjusted, but that is not hard, just time consuming to tune for steady pressure vs taste.

My Stradivari has never had an issue pulling shot after shot after shot, until it almost runs out of the 16 shot water limit. Others with Millennium models have stated the same.


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## jeebsy (May 5, 2013)

Dylan said:


> Are you trying to say that the superheated water cycling from the boiler is the same temp as the group?


If you keep putting water into the group that's the 'wrong' temp (whether that's too hot or too cold) the temperature of the group will move towards that temp. Use an HX as intended (ie pulling shots regularly) and it's all gravy


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## Dylan (Dec 5, 2011)

That doesn't change the fact that the water going into the group is not stable, ie not always the 'right' temp, and is regulated by the thermal mass of the group. The amount of water passing through the group is tiny compared to the mass of the group itself.


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## jeebsy (May 5, 2013)

If the water is consistently too hot to cold coming from the HX pipes then that will affect the group temp. Maybe not over one shot or three shots if the group was the 'right' temp to start with but it will eventually.


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## Rhys (Dec 21, 2014)

insatiableOne said:


> I agree with the lever part, being the way to go.
> 
> Just wish people would stop spreading fodder of the La Pavoni's can only make a couple of shots → then overheat.
> 
> ...


After more than a couple of shots, the portafilter bubbles at the spout. This to me, indicates that it's too hot. Also the portafilter is too hot to touch. Methods to counter this include putting the pf into cold water to cool it down, and/or wrapping a cold wet cloth around the grouphead. There's no cooling HX to flush, it's a grouphead bolted onto a boiler which could take the skin off your hand if you picked it up by the boiler. It can steam all day long though (as long as it doesn't run out of water..)


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## 4085 (Nov 23, 2012)

insatiableOne said:


> I agree with the lever part, being the way to go.
> 
> Just wish people would stop spreading fodder of the La Pavoni's can only make a couple of shots → then overheat.
> 
> ...


Total twiddle.....the La PAvs have no mechanism to control the temp of the group which is why after 2 or 3 shots being pulled you have to give it a rest or burn your drinks. What has 1999 got todo with it. I bow to an obvious lever expert, or atlas I will when I see one!


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## Dylan (Dec 5, 2011)

jeebsy said:


> If the water is consistently too hot to cold coming from the HX pipes then that will affect the group temp. Maybe not over one shot or three shots if the group was the 'right' temp to start with but it will eventually.


I am not saying its consistently one 'wrong' temperature, but that it is wrong in regards to the temp it should be, and that this wrong temp is corrected, or 'regulated' by the consistent temperature of the group.

The temp of the group is achieved from the boiler water, however the fluctuating nature of the water temp needs the stable nature of the group temp to achieve a stable temperature for the brew.


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## jeebsy (May 5, 2013)

Anyway, how are you going to inject this cold water?


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## Dylan (Dec 5, 2011)

jeebsy said:


> Anyway, how are you going to inject this cold water?


Ask Fracino/Rocket.

I'm not the one supplying the information, just repeating it, if you are interested/dont believe it then ask Fracino/Rocket or Riess.


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## jeebsy (May 5, 2013)

They use flow restrictors I think, injecting cold water was your idea?


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## 4085 (Nov 23, 2012)

Fracino use their own version of the E61 and as far as I know, the group on the Londinium does not mix cold water into itself. The temperature is held by constantly pumping water on a carefully considered route


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## risky (May 11, 2015)

Montana said:


> My routine is, warm the machine up go 30 mins, then a 6 second cooling flush and I'm good to go.


A few pages deep in discussion on HX vs. DB but I'd like to pick up on this.

This seems counter to all the temp surfing advice I've seen for the classic. Normal advice is, leave for 30 mins to heat up, wait for light to go out, wait for light to come on again indicating boiler is at minimum temp for pulling a shot, hit steam switch on for about 5 seconds to push the temp up so it doesn't drop too low during the shot, flick steam switch off and pull the shot.

I'd be amazed if your routine wasn't causing a very low temp shot?


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## marcuswar (Aug 19, 2013)

I agree with risky on this. Doing a cooling flush on the Gaggia Classic will result in low temperature shots if you don't also allow some time to recover. From my own experience and readings, the Classic doesn't really need a cooling flush as such as it's only a single small boiler. The temperature of the boiler is controlled by a simple thermostat on the boiler. The thermostat has quite a wide heuristic and so the temperature that it turns on and off at is quite wide for the purposes of making coffee.The flush is actually to "trick" the machine into a known state in its heating cycle. i.e. the lowest point that causes the heating elements to come on. This should then give a consistent starting temperature between shots. Starting from this known point you can then allow a certain length of time for it to recover which should then result in a relatively consistent average temperature between shots. Flicking the steam switch on is overheat the boiler above brew temperature in order to try and pre-compensate for the sudden inrush of cooler water into the small boiler when the shot is being pulled.


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## Dylan (Dec 5, 2011)

jeebsy said:


> They use flow restrictors I think, injecting cold water was your idea?


I'm not trying to create a design for a non flush e61 group, so I really have no 'ideas' about how they should work, just that others far more in the know than you or I have stated these machines already employ one design or another that achieves these ends, and this statement has been corroborated by owners of said machines.


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## marcuswar (Aug 19, 2013)

Since the thermosyphon is a closed circuit I can't see how you could inject cooler water into it without having some other mechanism to allow the venting of a similar amount of hot water from the syphon circuit. In other words it just then becomes an automated flush mechanism.


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## Dylan (Dec 5, 2011)

marcuswar said:


> Since the thermosyphon is a closed circuit I can't see how you could inject cooler water into it without having some other mechanism to allow the venting of a similar amount of hot water from the syphon circuit. In other words it just then becomes an automated flush mechanism.


In my earlier post I was just guessing at a method for cooling the brew water without a flush, I don't know the ins and outs of how the machines work, just that they have been stated and shown to not need a flush.


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## DavecUK (Aug 6, 2013)

Dylan said:


> I'm not trying to create a design for a non flush e61 group, so I really have no 'ideas' about how they should work, just that others far more in the know than you or I have stated these machines already employ one design or another that achieves these ends, and this statement has been corroborated by owners of said machines.


Don't believe everything you read and owners of any machine are about the worst people to look impartially at a machine. In fact most owners glowing comments are done in the first few weeks of ownership...so go figure. Theres a lot of marketing bollocks talked I am afraid and I have looked at so many machines and asked all these questions of the manufacturers and it's usually some small change that allows some marketing bollocks. In some cases on machines there are some dreadful design decisions some even require fudges to even make the machines work right.


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## marcuswar (Aug 19, 2013)

Dylan said:


> In my earlier post I was just guessing at a method for cooling the brew water without a flush, I don't know the ins and outs of how the machines work, just that they have been stated and shown to not need a flush.


Sorry Dylan, I wasn't having a go at you rather just musing on the principle in general


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## h1udd (Sep 1, 2015)

Well a decent dual boiler will be more consistant than an hx for knocking out shot after shot .... But you have to weigh up you drinking needs ... I bought an hx 9 years ago with the plan to upgrade after a year to a DB .... I am still using the hx ... At most I have made 4 shots in a row, normally it's 1 or 2 at a time, it stays on all weekend, a cooling flush is all it needs to get the brew temp back down, that cooling flush I use to preheat the cups.

i also bought a la pavoni ... It's my go to machine if I need a coffee in a hurry ... Cold to espresso/steaming temp in 7 mins ... I wouldn't want to make multiple shots on it, the boiler is too small, it gets too hot and if you rush her, she sneezes on you .... But if you are only making 2 coffees at a time it's an awesome machine


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## Dylan (Dec 5, 2011)

DavecUK said:


> Don't believe everything you read and owners of any machine are about the worst people to look impartially at a machine. In fact most owners glowing comments are done in the first few weeks of ownership...so go figure. Theres a lot of marketing bollocks talked I am afraid and I have looked at so many machines and asked all these questions of the manufacturers and it's usually some small change that allows some marketing bollocks. In some cases on machines there are some dreadful design decisions some even require fudges to even make the machines work right.


That would be one point you are contending, do you want to address why Reiss would make a blog post about it?

I came to believe it when I read what Reiss had said in his blog, and then following this an owner of a Fracino machine left it to idle for over an hour and then got a a temperature reading of just above 90.


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## Dylan (Dec 5, 2011)

marcuswar said:


> Sorry Dylan, I wasn't having a go at you rather just musing on the principle in general


Not at all Marc, I wasn't thinking you were having a go.


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## cold war kid (Mar 12, 2010)

DavecUK said:


> Don't believe everything you read and owners of any machine are about the worst people to look impartially at a machine. In fact most owners glowing comments are done in the first few weeks of ownership...so go figure. Theres a lot of marketing bollocks talked I am afraid and I have looked at so many machines and asked all these questions of the manufacturers and it's usually some small change that allows some marketing bollocks. In some cases on machines there are some dreadful design decisions some even require fudges to even make the machines work right.


I'm thinking of buying the fracino cherub but family commitments mean it's taking a long time to save so I've done a lot of research into this model and I can tell you for a fact that fracino don't use it as marketing bollocks. It's not mentioned in any of their official literature or their website. In fact it's such a little known fact that Even some owners don't seem to know it. Is it true? I'm afraid that like you I can only have my own opinion as I don't own one but several people who do own them have used the Eric's thermometer or whatever it's called to test temp and reported that it's consistent even after being left to idle for an hour of more.

For clarification I rang fracino and they confirmed this.If they never use this to try and sell more machines then why would they lie and why don't any customers ever call them out after running tests? It doesn't make sense in this specific case ( although I am willing to admit you could be right if talking of a broader, more industry wide problem).


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## DavecUK (Aug 6, 2013)

cold war kid said:


> For clarification I rang fracino and they confirmed this.If they never use this to try and sell more machines then why would they lie and why don't any customers ever call them out after running tests? It doesn't make sense in this specific case ( although I am willing to admit you could be right if talking of a broader, more industry wide problem).


Look, you guys believe what you want to believe if it really makes you happy. Otherwise do the research understand the science and see if what is said by various companies (remember I didn't mention any specific companies), tell you anything that makes scientific or mechanical sense...perhaps even try designing some stuff, or fixing other peoples design mistakes. Think hard about how many espresso machines from different manufacturers you have really seen, how many you opened up, how many you tested thoroughly. I made my version of a scace 2 long before a scace was invented, just so I could test claims of temperature in SBDU, HX and DB. It appears I'm never going to convince you, but just remember this, I don't sell espresso machines, roasters or anything else.

Theres a lot of marketing spin out there....but if you don't want to believe it...fine, believe the company making and selling the machine..


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## Dylan (Dec 5, 2011)

DavecUK said:


> Look, you guys believe what you want to believe if it really makes you happy. Otherwise do the research understand the science and see if what is said by various companies (remember I didn't mention any specific companies), tell you anything that makes scientific or mechanical sense...perhaps even try designing some stuff, or fixing other peoples design mistakes. Think hard about how many espresso machines from different manufacturers you have really seen, how many you opened up, how many you tested thoroughly. I made my version of a scace 2 long before a scace was invented, just so I could test claims of temperature in SBDU, HX and DB. It appears I'm never going to convince you, but just remember this, I don't sell espresso machines, roasters or anything else.
> 
> Theres a lot of marketing spin out there....but if you don't want to believe it...fine, believe the company making and selling the machine..


This is again to ignore the points about believing Riess or actual users of the machine who have observed it in practice.


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## DavecUK (Aug 6, 2013)

Dylan said:


> This is again to ignore the points about believing Riess or actual users of the machine who have observed it in practice.


Well I try not to ignore science and the laws of Physics, I'm also pretty good on the design side for the Hydraulics and thermodynamics now....plus remember, I don't sell machines or make my living by you buying a particular machine. I've no axe to grind either way. Whatever others have observed, I don't know the equipment, the conditions or the method....I just have experience, a lot of it. The sort of experience that allowed me to look inside a the QM Veloce Lever machine and within 60 seconds state why the group was going cold and how QM could fix it....which they did....just physics.

I just trust in science, always have...then if you observe something counter to the laws of physics, you're measuring it wrong, or not considering something. it's like the old chestnut of how Espresso machines use less power if they are left on all the time, than if they are switched off for a more than a few hours if you're not using them. In fact their reasoning is so seductive, that they really believe a commercial machine left on for 24hrs costs less in electricity than one switched off every night the cafe closes. They really believe that if you switch off your espresso machine if your not going to use it for a few hours, costs more in electricity. They can even produce graphs and charts showing this, or recite anecdotal "evidence". However, physics is physics, free energy, over-unity doesn't exist. Once you switch the machine off, you are saving power, even if 30m later you switch it back on, you still saved power.

Or one of the Indiegogo machine that used Halogen rods in a tube to heat the water in an espresso machine and claimed it was more efficient than a conventional heating element. They even showed a photo of it operating and you could see the glow of the halogen rod inside the tube. That photo in itself disproved that statement of efficiency...it glowed (loss of energy), it was an open tube (convection loss of energy)...so not as efficient, like a conventional immersed element. It's just hype re efficiency, not science.

https://www.indiegogo.com/projects/the-new-water-heating-technology-by-avelon-3gt#/

Or perhaps this floats your boat, mighty convincing, but if you know anything about the science of batteries....perhaps it raises some questions. But of course 7500 people can't be wrong can they, surely not....they all invested...it must be me who is wrong.

https://www.indiegogo.com/projects/batteriser-extend-battery-life-by-up-to-8x#/


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## Dylan (Dec 5, 2011)

I would say Reiss knows an awful lot about espresso machines as well. These aren't pie in the sky indegogo campaigns, but produced machines with observable results from owners with no commercial gain to be made.

You keep claiming these machines break the laws of physics dave, it's a nice statement to throw around but you have no backing for it other than the belief in your own superior knowledge. It certainly isn't against the laws of physics to cool down water, there are one or two perfectly scientific ways to do that.


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## insatiableOne (Jul 29, 2015)

dfk41 said:


> Total twiddle.....the La PAvs have no mechanism to control the temp of the group which is why after 2 or 3 shots being pulled you have to give it a rest or burn your drinks. What has 1999 got todo with it. I bow to an obvious lever expert, or atlas I will when I see one!


If you read the entire post La Pavoni took great steps in correcting the overheating problem, starting with that date. At the Millennium, they claim stability issues were much better. Don't have one, just stating their facts along with other users with the Millennium models.

I can verify the Stradivari fixed the issues of decades of faults, as I have none stated here.

If you are using a Europiccola, or Pre-Millenium model, that statement is misleading as the issues still affect them. That is why they said 1999 & ↑, as the Milleniunm was supposed to be the problem solver.



Rhys said:


> After more than a couple of shots, the portafilter bubbles at the spout. This to me, indicates that it's too hot. Also the portafilter is too hot to touch. Methods to counter this include putting the pf into cold water to cool it down, and/or wrapping a cold wet cloth around the grouphead. There's no cooling HX to flush, it's a grouphead bolted onto a boiler which could take the skin off your hand if you picked it up by the boiler. It can steam all day long though (as long as it doesn't run out of water..)


I can only state that my Stradivari has been on more than 24 hrs as of now, pulled about ten shots since then. Pulled the fourth temp was 194° after the last shot. The shots always flash boil at the very very end. End the pour before then, it is like clockwork_

I had to actually turn my boiler temp up, many others have stated that they needed to turn theirs down. Pretty easy to remove the base plate, & turn the boiler screw. Counter-clockwise → turn temp down. Clockwise → turn temp up. (should I state pressure) Mine is steady at 8.5 bar. of course it fluctuates slightly when the boiler cycles on & off. Took some effort adjust, to make it stable though. Not all geography is the same, affecting altitude and humidity.

I think an issue still, is that they have not fixed the Europiccola, or Pre-Millenium models since their initial release.

Try the newer stuff, you might just like it, more stable, bigger boiler. Go from just being able to steam to pulling continuous shots with them.

Just goes without saying these are an open boiler design with an exposed group.

(pg #19 starts English) not 35.

The owners manual..

Do not touch the hot surfaces (boiler, unit, filter holder, steam supply nozzle)to avoid burns.

Do not remove the filter-holder during coffee delivery, to avoid possible burns.

Do not remove the boiler cap when the machine is working or still under pressure, to avoid possible burns; first you must switch the machine off, then slowly unscrew the steam tap knob and wait for all the steam to have been discharged from the relevant tube; subsequently remove the cap.

Under no circumstances you must put your hands under the unit and the steam supply nozzle, since the liquids or steam delivered are overheated and may cause burns.

After coffee delivery, do not remove the filter holder immediately, but wait for a few seconds to allow the possible residual pressure to be released, to avoid possible burns.


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## 4085 (Nov 23, 2012)

Dylan, if you think somehow cold water is introduced into the system, then it ought to be easy enough to find examples. You quote the Londinium. Having had one and been inside it plenty of times, I can tell you that whether tank fed or connected to the mains, the cold water feeds the boiler which in turn feeds the thermosyphon which loops from the boiler to the group........no cold water feed in sight. The loop controls the water temperature which is why on an L1 once you have pulled the shot if it is not going to be used again quickly, best practice is to pull a short flush to make sure the syphon kicks back in and re starts


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## 4085 (Nov 23, 2012)

insatiableOne, can you explain how the machine deals with temperature stability then. What mechanism that caused pre 1999 machines to be incapable of producing more than 2 or 3 shots on the trot has been modified in someway by the Millennium model?


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## insatiableOne (Jul 29, 2015)

Simple search for credible reference.

Article explains it well.

http://coffeegeek.com/proreviews/detailed/pavoniprofessional/history

*In 1999 La Pavoni set out to correct this imbalance, a year later the MILLENIUM models came to market. A novice would be hard pressed to see the difference between the two units beside the fact that the group on the Millennium is larger, however, internally many changes took place.*



*
(The move to a) larger group solved two problems, it allowed the water in the group to sit in a larger area which would allow the water to mix with air and cool naturally. The water would also cool faster if it did not come into contact with metal; so the group is now lined with a nylon sleeve made of ryton, effectively placing a vacuum barrier between the water and metal wall.*



*
Last, a vented spacer was fit between the group and the boiler, this perforated spacer allows excess steam to travel up, away from the water and back into the boiler. A larger handle, screen and filter basket round out the changes. *

*
*

*
Specifications of changes are as follows:*

*
Filter holder: now 59.5 mm up from 57.5 mm*

*
Upper zone of group: now 60 mm up from 50 mm*

*
Internal Screen: now 50.5mm up from 48.3*

*
Filter basket: now 53.5mm up from 48.3*



*
After testing, the final results indicate a drop of 6% - 9%, or 10-15 degrees F between the units. Testing was done during a four-month period with temperature changes ranging from 54 degrees F to 77 degrees F*



*
*The newer units are identified with a large silver sticker indicating the world "Millennium" attached to the bottom of the base. We would like to thank Mr. Forzano for this valuable information. Because we are limited to testing our model on hand, (a pre-Millennium design), we must limit our direct comments to our test model; however, some of our comments and criticisms of the La Pavoni Professional machine in this Detailed Review may already be moot points with the new unit. The news about the baffles in the channel between grouphead and boiler is especially promising, and the larger grouphead is not only a boon to better temperatures over consecutive shots, but also a boon for richer espresso due to the (assumed) larger amount of grinds that can be used for each single or double.

Edit: My addition is to also be certain to release false pressure before pulling a shot. (through steam wand) Air + steam can be compressed.


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## Dylan (Dec 5, 2011)

dfk41 said:


> Dylan, if you think somehow cold water is introduced into the system, then it ought to be easy enough to find examples. You quote the Londinium. Having had one and been inside it plenty of times, I can tell you that whether tank fed or connected to the mains, the cold water feeds the boiler which in turn feeds the thermosyphon which loops from the boiler to the group........no cold water feed in sight. The loop controls the water temperature which is why on an L1 once you have pulled the shot if it is not going to be used again quickly, best practice is to pull a short flush to make sure the syphon kicks back in and re starts


The Londinium article has nothing to do with the L1 and I'm not going into how I don't think cold water is introduced for the second time in one thread.


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## jeebsy (May 5, 2013)

Dylan said:


> The Londinium article has nothing to do with the L1 and I'm not going into how I don't think cold water is introduced for the second time in one thread.


You suggested it as a simple solution to HX water overheating, where's the working prototype?


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## GlennV (Mar 29, 2013)

There seem to be a couple of discussions going on in parallel here. I shall restrict my comments to pumped HX machines. Most (and perhaps all) inject cold water into the thermosiphon circuit when pulling a shot (it's this that forces the brew water out). Having fixed the steam boiler temperature, there remain three tuning parameters, the size of the restrictors in the feed to and return from the group and the length of the injector tube (controlling the point at which the cold water is injected). The combined effect of the restrictors controls the steady state group temperature, the balance between them controls how much of the brew water is taken from the (hotter) upper and (colder) lower feeds. It is entirely believable that these three parameters can be tuned to give the desired brew water temperature for both walk up and follow on shots. It would appear that many manufacturers don't bother though (and indeed, many can't even be bothered to tune the PID parameters on DB machines).


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## Dylan (Dec 5, 2011)

jeebsy said:


> You suggested it as a simple solution to HX water overheating, where's the working prototype?


I couldn't possibly show you my prototype, it clearly breaks the laws of physics and as such will change the world as we know it.


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## jeebsy (May 5, 2013)

Dylan said:


> I couldn't possibly show you my prototype, it clearly breaks the laws of physics and as such will change the world as we know it.


Better watch or the new world order will be after you


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## Montana (Jan 3, 2013)

few pages deep in discussion on HX vs. DB but I'd like to pick up on this.

This seems counter to all the temp surfing advice I've seen for the classic. Normal advice is, leave for 30 mins to heat up, wait for light to go out, wait for light to come on again indicating boiler is at minimum temp for pulling a shot, hit steam switch on for about 5 seconds to push the temp up so it doesn't drop too low during the shot, flick steam switch off and pull the shot.

Given this a go for a few days now and it's a lot better than my old routine!! Tastes great with no milk at all, thanks for the advice. Think I'll go down the leave route, just need a nice L1 or similar to come up used now.

Thanks Rich.


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## risky (May 11, 2015)

Great to hear it helped!


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