You won't be messing with the Pstat, you will be doing cooling flushes to get a desired temp. In all fairness if you want the best of both worlds considering your options, get the rotary pump machine and add a group thermometer. Like countless others before you here have done with their non PID machines. It's more difficult to explain cooling flushes then it actually is to do.

HRC-E.B. wrote:Question: on a stable HX (i.e., one that needs little to no cooling flushes to brew at about 200 F) how does one raise brew temp slightly to better fully extract the oils from lighter roasted coffees?

Is the PID of any real assistance in such a case? Or, because it's an HX and the brew water is fresh water going through the exchanger, is there a real effect on brew water temp to raising the steam boiler temperature via the PID?

Clearly, this is easier to do than opening up the machine to tweak a pressure stat, what I'm wondering is the actual impact on brew temp of doing so?

The brew temperature can be adjusted up or down using the PID. The owner's manual will supply a chart showing the group head temperature at the chosen PID setting.

bluediesel77 wrote:You won't be messing with the Pstat, you will be doing cooling flushes to get a desired temp.

+1

bluediesel77 wrote:It's more difficult to explain cooling flushes then it actually is to do.

Well said. Like driving a stick shift and a clutch; you get the feel of it and it's easy - even a little fun if you like being physically in control of the machine.

To be able to do "cooling" doesn't one need to have a machine that runs slightly too hot (i.e., over the desired brewing temperature) to begin with?

I was given to understand that Rockets come set up in a way where they require basically no flushes, or very little (because of the way their thermosyphon and restrictor work). So if they come set to work at around 200F and I can only cool it down further, what do I do if I want, say 205F for a lighter roast coffee?

My understanding of the Pro 500 PID based on stats published in another thread is that the PID adjustment range results in the ability to brew anywhere between 198 and 206, essentially.

But to get that, as mentioned above, I get a tank-only and vibe pump machine where I would have wanted a rotary and switchability to go along with the temperature adjustability.

Turn up the PID for higher temperature. Very little flushing is necessary. Both machines operate in a similar fashion.

HRC-E.B. wrote:To be able to do "cooling" doesn't one need to have a machine that runs slightly too hot (i.e., over the desired brewing temperature) to begin with?

I was given to understand that Rockets come set up in a way where they require basically no flushes, or very little (because of the way their thermosyphon and restrictor work). So if they come set to work at around 200F and I can only cool it down further, what do I do if I want, say 205F for a lighter roast coffee?

My understanding of the Pro 500 PID based on stats published in another thread is that the PID adjustment range results in the ability to brew anywhere between 198 and 206, essentially.

But to get that, as mentioned above, I get a tank-only and vibe pump machine where I would have wanted a rotary and switchability to go along with the temperature adjustability.

Both machines PID settings can be changed to get higher or lower brew temps. But also take into consideration your steam pressure will also change. Now your not going to get DB PID control on a HX PID machine, let's just get that out of the way shall we. I have a hard time believing your not going to need cooling flushes if left idle for a long time.

The thermosyphen restrictor helps keep the E61 brew group on a HX machine at a stable temp. All Rockets HX E61 machines come with one, even the Evo V2.

turbo290 wrote:Turn up the PID for higher temperature. Very little flushing is necessary. Both machines operate in a similar fashion.

I think you may have missed a nuance in my posts: the Rocket I'm looking at has no PID, but a pressure stat instead. The Profitec has a PID.

How was wondering if I can expect to be able to do the same time with the machine that has a PSTAT instead of a PID. (Rocket does offer a rotary PID machine, but it's a different model that is almost 50% more expensive than the one I'm considering.)

Here is a pstat HX example of a flush and brew. Notice it only took a little over a minute.

kolu wrote:most of italian coffee machines could be fixed by hammer.

yea, 2,5 mm restrictor will work, it doesn't matter if it is brass plug or teflon/copper washer. just drill 3 mm hole there and flip it anywhere to the upper HX tube (the connection between boiler and pipe is actually the better place for washers).
I actually have done my own restrictor for Grimac a while ago, even with matching thred in the HX tube. It is just a something with a hole inside, no magic.

I see what you did there, i have same sentiment towards other engineering marvels from the good folks in italy!.

Good point, i may source out solid washers and buy a whole bunch then i can play with different hole sizes!!!.

Did you install it at the inlet pip leaving the boiler or the inlet pipe leading to the e61? I suspect it wouldnt matter where to install it but i suspect to keep the thermal loss at minimal it would be better at the pipe leading to the e61 grouphead.

HRC-E.B. wrote:I think you may have missed a nuance in my posts: the Rocket I'm looking at has no PID, but a pressure stat instead. The Profitec has a PID.

How was wondering if I can expect to be able to do the same time with the machine that has a PSTAT instead of a PID. (Rocket does offer a rotary PID machine, but it's a different model that is almost 50% more expensive than the one I'm considering.)

My opinion is biased as to which one to pick, because i went to a store and looked at both machines and used both machines. I found the profitec to be better built and had less flex in the whole body while moving it (you rarely will notice this). I would suggest you find both machines nearby and go look at them and pull lever etc to get a feel for the quality.

In terms of PID vs PSTAT, it would be a close difference in terms of temperature stability. The pid wont have a temp swing delta as big as the pstat machine. But if you think you are not going to do any cooling flushes, that is not going to be the case unless you are only making one drink at a time. If you want to make more than one drink and get to know the machine and how it reacts to cooling and then heating back again. The only reasons the restrictor comes in handy is to minimize the temp swing throughout the shot. The restrictor is not going to make flushing history, especially if you are making more than one drink at a time.

Pros of the rocket are:
- the Rotarary pump.

Pros of the Profitec are:
- (to me) are the build quality and then
- pid is a pro.
- no click clack of the pstat
- stainless steele boiler (less prone to scale - but copper pipes all around)
- Spring loaded valves (thanks tanax)

I am still learning how my machine works... i have used it for months at 1bar max, then 1.1bar now 1.2bar. I am beggining to get a feel for how to get a stable temp and a decent shot.

Just see what was important to you, if i had this choice knowing what i know the rotatory pump is an attraction to me but not enough to jump ship, especially when profitec is now fitted with a restrictor.

HRC-E.B. wrote:To be able to do "cooling" doesn't one need to have a machine that runs slightly too hot (i.e., over the desired brewing temperature) to begin with?

Yes, the machine at idle comes up to a "too hot" temperature, and you flush it down a lot for a cool brew and flush less if you want a hot brew. If you have not yet read it, see this HB article about the fundamentals of HX machines: Managing the Brew Temperature of HX Espresso Machines

HRC-E.B. wrote:I was given to understand that Rockets come set up in a way where they require basically no flushes, or very little (because of the way their thermosyphon and restrictor work). So if they come set to work at around 200F and I can only cool it down further, what do I do if I want, say 205F for a lighter roast coffee?

My current Rocket (Evoluzione V2, 3mm restrictor, with pStat set to ~1 bar) requires a flush of appx 140 ml to get a ~200F shot if the machine has been idle for a long time. (My idle group temp at the EricS thermometer runs about 203F.) Subsequent shots require nothing more than a quick screen cleaning flush even if I spend a couple minutes preparing each next shot.