Radio.YYZ wrote:What about the rocket machines they come with one, couldn't the restrictor be installed in the profitec? Or rocket sells them as a whole unit? PTFE or brass on rocket?

I suppose we have to wait and see how it pans out, my top of pro500 is open so installing the restrictor would be a breeze if i can source the right one!

It sounds like it's only a "plug" with a hole in the middle to restrict flow. If you could find the dimensions you could probably get a local machine shop to pop one off for cheap


Randy

Yeah, it is usually just a 1mm thick washer that is around 18mm in diameter and then a hole in the centre. I may have to get it made or find one in a hardware store but i figured id see if they are making one that slides into the pipe and is actually a plug rather than a washer!

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

Raising the boiler temp will raise brew temp. I don't think it's directly proportional but it will definitely have an effect on brew water. The e61 group would smooth it out a little as it's colder than the water passing through the hx. This is where Eric's thermometer would be handy. I have no real way of measuring brew temp. I'm just going with what tastes good to me.

kolu wrote:we order spares directly from manufacturers + quite a lot from LF spare parts, but they sort of have no restrictors except for the #1186030, 18x3,5x1 mm flat PTFE gasket from Expobar, bit too open (3,5 mm) if you ask me.

WLL has a 2.5 mm teflon washer restrictor that fits the Expobar (fitting at back of group). Is 1mm thick and 18.2mm diameter - (currently can be found here.)

According to the Rocket parts lists, that brass plug comes with the Rocket inlet tube. But machine vendors might be able to sell you one separately. I understand they can be pressed into the fitting with a hammer.

HRC-E.B. wrote:Clearly, this is easier to do that opening up the machine to tweak a pressure stat, what I'm wondering is the actual impact on brew temp of doing so?

You've hit on the main functional advantage of a PID/SSR (over a pressurestat) on an HX machine. Either method controls the steam boiler temperature, and indirectly controls the idle temperature of the group, and the temp of the water in the HX before you start flushing. But on a PID machine it's dirt simple to raise the boiler temp a couple degrees, then wait for the machine to equilibrate (which could take 10-20 minutes) if you think you need a hotter machine. (I agree there are other advantages to the PID with SSR switching related to reliability, and related to using the same components in both DB and HX models from a given manufacturer.)

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?

I suppose then you'd have to raise the PID setting, wait 10 or so minutes for the group heat to catch up, then try your pull. If you have an HX that requires no cooling flush to brew at 200F, in my opinion you have a less than ideal machine setup. Besides the issue that the boiler pressure may be too low for good steaming, or perhaps the thermosyphon action is too slow to recover when making successive shots, you are missing a key benefit of the HX: An HX lets you immediately try a hotter than normal shot simply by using a shorter cooling flush and/or shorter wait after the flush. It's a very old-fashioned hands-on (and imprecise) method, but it works nicely once you get used to it. For me, I need the help of an EricS thermometer to learn and tune that technique.

I think the main advantage of an HX / E-61 machine that has been tuned to work well with little or no cooling flush is that it will would work nicely for those consumers who want to walk up to a long idle machine and pull a drinkable espresso, then quickly pull four more drinkable espressos in a row and not concern themselves with really geeky details of cooling flushes. Then, if that machine has a PID, when changing to a new coffee they can use the PID to easily experiment and taste, which after a few tries should get them to a good temp for the new coffee.

homeburrero wrote:I understand they can be pressed into the fitting with a hammer.

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.

A lot of talk about cooling flushes.

I have another viewpoint: I want to do a flush (technically not a cooling flush but just a flush) because I want the freshest water possible -- to get the water out that has been staying inside the HX system (tubes). I would want to avoid water that has been idling/heating in the copper tubes, which might not be the safest material because of any lead they may contain.

I have a rotary pump + plumbed in HX machine because of this.

Anybody else thought of this? (And yes, I know that the pipes that come into the house may have their own problems, but I will have to live with that.)

you can flush like 0,3-0,5 l and then wait until the group heats back up. could be few minutes though...

I have been doing this. Although, I only drink one cup of coffee per 48 hours, so it's not too bad.

And: I had been wondering what the amount of water would be that I need to flush. I guess I have been estimating similar amounts...

Still debating. I think I could go back and forth forever.

Bottomline for me: if the Pro 500 PID was switchable and had a rotary like the Rocket V2, that's what I'd pick. I like going back and forth between a darker blend and a lighter blend, and I can be assured that while the Rocket may be great for either, it won't be great for both unless I open it up to play with the pstat, and even then what temp am I getting for any adjustment?

At the same time, it pains me to think that I'd pay over two grand for a coffee machine and have to compromise in not getting premium features like switchability and a rotary pump. Or have to settle for a technology (or lack thereof) that will have me guessing at my temperatures.

Of course I understand that a Rocket Evo R or a Profitec Pro 700 would solve that, but at more than $700 or $1500 extra over the other 2200 investment, respectively, we have left the realm of "reasonably accessible" for that of the truly very expensive...

So? Rotary plumbable pstat Rocket? Or PID easily temp adjustable vibratory Profitec??? I just can't decide.