HX Machines - Cooling Flush

Reschsmooth

G'day, I just wanted to get some feedback from those with HX machines (home machines) - if your machine has been idle for quite some time (say 1hr or more) how long do you run your cooling flush (time/volume of water) before you pull the next shot? What boiler temp (in bars) do you run?

I haven't measured mine yet, but, at 1.2 bar, I reckon I need to flush about 500 ml (I might measure it tonight) before the water stops steaming and runs 'smoothly'.

Interested in your feedback.

Cheers

P

mimmo124

Hi Reschsmooth, On a La San Marco machine (Commercial) I run the flush until it stops spitting and hissing steam. This varies with each group and the ammount of time it has been left idle. In terms of volume 500ml seems a lot, but maybe thats normal on a domestic HX machine?? Either way I run a cooling flush like that for almost every shot while I am grinding/dosing/tamping etc. I usually run it on one of the preset buttons and change the button I press for the length of time its been idle. Hope this helps? Mimmo

nunu

I have to run cooling flushes even between shots.  I run the notoriously hot San Marino CKX.

mattyj

geez ... a half-litre flush ... that's massive! For some reason, I do two flushes, which will vary in length/volume, depending on where in the boiler cycle the machine happens to be. I'll flush until the boiler light comes on, stop, wait til the light goes out, flush again until the light goes on, stop, wait til the light goes out, then pull the shot. I don't focus on it too much, becuase while it's flushing, I'm preparing the puck (distributing, tamping, wiping off the rim of the basket etc. Between shots (if they're back-to-back), I'll do the flush-til-boiler-light once. But that depends on how quickly back-to-back is...

Bon

Matty, can you elaborate on that or provide any links on the subject? This is currently driving me insane! It's something I've been playing around with ever since I had a couple of really good shots in Sydney and noticed how drinkable they were straight away with more intense flavours, compared to mine which were a little hot and bitter. I flush before I lock the group handle in and depending on what beans I'm using, for most of them it seems a longer purge is required compared to my programmed purge. Today I noticed with a guatamalan that the ones I pulled in the morning with a slightly longer purge still tasted ashy and burnt, reminding me of a cafe around here.. but, the ones I pulled in the arvo with an extremely long purge in comparison were much better and 'rippers' according to friend of mine. My shots are often too sour, or too bitter... I can't get the happy middle ground, help please!  ;D

FreshCoffee2

Patrick, call me if you are concerned. Bon, without knowing what type of machine you have it is difficult for anyone to advise. Regardz FC.

Bon

sorry, it's an ECM Veneziano A1.

mattyj

Hi Bon, Actually, one of the biggest problems I've had to overcome that directly affected the taste, was my dose and distribution. For a long long time I thought it was the cooling flush, that my machine was rebounding to too hot too quickly, that my boiler pressure was too high ... But lately I've been focussing on my dose and distribution. If you're getting bitter ashy shots, watch the streams coming from the spouts. If they're thin and slow and you end up with a short ristretto, you're probably updosing too much. Once that naked portafilter arrives, you'll get to see which parts of the pucks are being extracted, and which parts are just too densely packed ... I'd suggest preparing a shot (grind, dose, tamp), and then insert the portafilter. don't pull a shot, just remove the portafilter, and look at the top  of your puck. If some of it is missing, it's now stuck to the shower screen, you've overdosed. I'll tend to dose to a mound, even out the mound with my finger, swipe the top off, wipe the rim of the basket and tamp. I don't tap the portafilter with the tamp anymore, and I din't polish the surface of the puck by twisting the tamp. I used to tamp with just about all the weight I could, but it seems unneccessary now. Of course, my method works well with my machine. Your grouphead/gasket/shower screen/basket are all probably slightly different to mine, so play with the naked portafilter unitl you find a method that works for you!

Reschsmooth

I too have been focusing on the distribution and reducing the weight with which I tamp and have been happier with the results, particularly since I have been purging more water. I have also reduced my dose quite a lot lately and have found that that helps considerably. Thanks for the offer FC - it isn't a problem for me to run the water for 30-60 secs however, I do have a slight concern as to whether this will affect the longevity of any of the components of the machine. Cheers P

Bon

Matty, I think I've actually been under dosing lately, I've been removing a soggy puck every now and then... I've updosed a bit more, read a few articles on HB about HX that Luca steered me to and I've pulled some of my best shots to date - I've just come off 5-6 coffees, my head is spinning and I'm going back for more! I pulled a ripper of a double ristretto just then, the thickest and most viscous body with intense flavours... and the finish and aftertaste, could feel the juices crawling on my tongue for a bit afterwards!! It sent shivers down my spine  ;D

Bon

I should elaborate, I think it was just a matter of a cooling flush (helps now I know what one is) if the machine's been sitting there idle for some time, or if I've made a milk-based drink - didn't understand the steam required a higher temperature, this is why water spits out of the steam wand initially I assume until the temperature picks up and produces steam? The cooling flush seems to have solved my problems and frustrations, I'm now pretty happy with the shots I am pulling!

sharkboy

Hi Bon, How have you been? You'll have to come around and check out my new machine. Any water from the steam wand is just condensation. Not water that hasn't been heated to the point of turning into steam. Steam is constantly available and there is no heat up stage, at least that is the case with your machine (HX) anyway. Thermoblocks and smaller single boiler machines may produce water from the steam wand when optimal temperatures are not obtained. The coffee I had from your A1 was great. Stephen.

Bon

Stephen, what machine did you end up getting again? I assume you would be pulling commercial standard coffee now mate Thanks for the clarification on the steam! I'll shoot you an email about checking out your new machine... If a cooling flush is required after using the steam, how does using steam at the same time a shot is being extracted affect the temperature and the shot? I kind of have limited space around my machine and grinder, so tend to pull a shot, then stretch the milk afterwards.

mattyj

hey Bon, good to hear that you're pulling nice shots! It seems to me that hx machines produce their best shots at about the 3rd or 4th shot in ... partly maybe because there's an equilibrium happening with boiler temp/hx temp etc ... dunno. They're kinda made for pulling successive shots I hear.

Remus

500ml flushes ? lol

Lovey

I know this topic is a bit old, but I only just remembered to measure my 'cooling flush' this morning