When is the end of the HX water dance? [video]

Beginner and pro baristas share tips and tricks.
bas

#1: Post by bas » Sep 27, 2009, 2:42 pm

Who can tell me at what point in this video the end of the water dance is there? I'm using a Magister Stella E61 HX machine. Internals are pretty much the same as the QM andreja apart from the OPV on the cold side and a flow restrictor. Pstat upper limit is 1.1 bar.

The flash-boil stops after just a few seconds but it takes a while before there is a steady pour and no audible hissing at all. Do the same flush and rebound principles as explained in HX Love apply with a flow restricted group head. Idle group head temperature is about 196-198 degrees F when measured from the outside with a simple digital thermometer. Is this representative? Until now I just flush for a couple of seconds and immediately lock and go. Do I get more stable temps by flushing more and waiting for half a minute or so?
Thanks :D

<missing video>

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HB
Admin

#2: Post by HB » Sep 27, 2009, 3:01 pm

The hissing stopped around 11 seconds and the water quiesced moments thereafter. Knowing nothing about your coffee preferences or the particular HX espresso machine other than the video above, I would try 4 seconds past the end of hissing, wait 10-15 seconds, then pull the shot. Fine tune to taste:
  • Bitter, hotplate flavor - flush an additional 5 seconds, increase rebound 5 seconds; this flushes more water from the HX and compensates by allowing the grouphead a few extra seconds to stabilize.
  • Mixture of sour/bitter - shorten flush by 3-5 seconds, shorten rebound by 3-5 seconds; this avoids overcooling and then overshooting temperature, i.e., the dreaded "U" brew temperature profile.
  • Somewhat sour, dull flavor - shorten flush by 3-5 seconds, keep rebound the same or increase slightly if it shows previous symptoms. Note: I find that lightly roasted fruity single origin coffees often taste better with this low hump, declining brew temperature profile than chocolaty blends.
There's no science to the above, it's purely guesswork based on lots of practice. If you want to reduce the guesswork on the cheap, search the FAQs, there's plenty of previous discussion in threads like Seeking low tech way to measure brew temperature, What's necessary to make a thermocoupled portafilter?, and Can't tell when the HX water dance ends.
Dan Kehn

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GC7

#3: Post by GC7 » Sep 27, 2009, 9:03 pm

From the video I had a point from about 11-14 seconds where I could have considered the flash boiling ended. I could be somewhat consistent with this method as well documented in the links given to you above. However, and its a BIG HOWEVER, I could never get my temperatures regulated as well or as consistently using the "end of water dance" method as I can using the grouphead thermometer probe invented by EricS.

http://www.chriscoffee.com/products/hom ... mometerkit

It to me and I think everyone else whose used it is an indispensable part of making excellent espresso with e61 grouphead HX machines. It is a great investment that will pay for itself in coffee saved from the sink :!:

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sweaner
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#4: Post by sweaner » Sep 27, 2009, 9:19 pm

I thought it was around 14-15 seconds.
Scott
LMWDP #248

www.coffeefreek.com

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Fullsack

#5: Post by Fullsack » Sep 28, 2009, 12:09 pm

For me, it is easier to identify the end of the water dance when I have a single spout portafilter attached to the group.
LMWDP #017
Kill all my demons and my angels might die too. T. Williams

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cannonfodder
Team HB

#6: Post by cannonfodder » Sep 28, 2009, 12:10 pm

I was thinking around the 14 second mark as well. Even if your group idles cool, the water in the heat exchanger is still superheated and needs to be flushed out. The cool group will also absorb some of that heat and raise its temperature. I would start with Dans recommendation and simply bracket your shots in either direction by 5 seconds until you find the flush/rebound timing that suits your taste and the coffee you are using.
Dave Stephens

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RapidCoffee
Team HB

#7: Post by RapidCoffee » Sep 28, 2009, 1:36 pm

Fullsack wrote:For me, it is easier to identify the end of the water dance when I have a single spout portafilter attached to the group.
Really? I find it much easier without the PF attached, or with a bottomless PF.
John

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Fullsack

#8: Post by Fullsack » Sep 28, 2009, 1:43 pm

It runs smoothly instead of bubbling down the spout.
LMWDP #017
Kill all my demons and my angels might die too. T. Williams

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JmanEspresso

#9: Post by JmanEspresso » Sep 28, 2009, 1:56 pm

My first reaction was at 12 seconds. After watching it again.. I would now say between 11-13.

With a 1.1Pstat reading.. I would personally use the "flush and rebound" method.. As Dan lined out. Im running just a tad hotter then you are, ~1.2BAR, and that is my preferred flush technique. Since Ive got the E-61 group Therm, Its been a while since Ive timed the flush.. But I can say my rebound time can be between 20-40 seconds.. Usually 20-25 gets me in the range.. Depending on the flush length.

It really is trial and error, and going by taste. A timer to time your flushes might speed things along a bit, so you can remember what you liked and what you wanted to change.

And I too will recommend the E-61 Group Therm.. It is an invaluable tool for E-61 HX's... Turns a guessing game into more of a sure thing. You still need to experiment.. But it makes it much easier.

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HB
Admin

#10: Post by HB » Sep 28, 2009, 9:51 pm

JmanEspresso wrote:But I can say my rebound time can be between 20-40 seconds.. Usually 20-25 gets me in the range.. Depending on the flush length.
Other HX espresso machines don't have as long a rebound time as your Anita, I assume because Quickmill mounts the over-pressure valve on the hot side of the heat exchanger. I'm not aware of another prosumer HX espresso machine with similarly located OPV.

Image
Diagram courtesy of erics from Can anyone explain preinfusion on the E61?
Dan Kehn