I have been using a HX espresso machine daily for the past 5 years. I upgraded a few months back to a Alex espresso machine so I could plumb-in. I have been pulling shots that I have been pretty happy with using the flush-and-go technique, which I used on my previous machine as well. I would characterize the Alex's behavior at least how I have it setup as a "HX dragon". I have had the curiosity to experiment, so I ordered an EricS adaptor. My pressurestat is set at 1.3 bar at the top of the cycle and I have been targeting a brew temp of 201F with the current blend I am pulling. I have been flushing about 5 seconds past when the water stops flash-boiling (a little over 8 ounces when idle), which also gives me 201F consistently using the styrofoam cup method. I installed the thermometer adaptor today and with my initial testing, I am stopping my flushes around 210F on the thermometer. The temp continues to drop a couple degrees after stopping the flush. I then pull my shot within a few seconds and it usually starts around 206, dropping steadily over the next 6 or 7 seconds and then runs at a pretty steady 202.5F through the rest of the shot. How should I interpret these results and how would this correlate to puck temps? Can I assume 202.5F is what the puck is seeing, or would there be an offset to take into account? This seems to be very different from what I have read from others, so any suggestions or tips on how to improve my techniques or at least interpret the results would be greatly appreciated.

The therm is a few inches above the puck, so, IIRC, the temp you're seeing is 3-4F higher, then what the puck sees.

Further more.. around to 25s mark, during the shot, the therm should be the approximate brew temp.



However... Running an E-61 as a flush and go, IMO, requires a bit of a higher P-stat setting. Member TimEggers is a flush-and-go advocate for his machine, and he runs pretty darn hot, up around 1.45BAR, IIRC. I used the flush-and-go for a bit when i had the Anita, and I cranked the P-stat up to 1.4B. But, them temps your seeing sound about right.. but, dont hold me to it. Your tastebuds are your best guide.. Cliche', sure.. but cliche's are so for a reason... cuz' they're true!

Thanks, those graphs are exactly what I was looking for. Based on the graphs, I should be flushing a bit longer no matter if I am using the flush-and-go or the flush-and-wait method than what I am currently doing. It still seems odd to me that I am seeing as high grouphead temps as I am with my technique. If I'm understanding correctly, the grouphead thermometer temps will be a couple degrees lower than what the puck is seeing if using the flush-and-go method. If using the flush-and-wait method, the differential will be the other way around with the grouphead temps about 3-5 degrees higher than puck temps. I usually pull two shots in fairly quick succession (within maybe 2 minutes of each other) in the morning. Can I safely assume that the grouphead temps with correlate the same with puck temps with both shots? I would love to stick with the flush-and-go method if at all possible because it saves me time in the morning when I am already usually running behind, but if I can greatly increase consistency, I will look at changing.

Well, after using the thermometer for the past week I am already pulling better shots than I ever had before. What surprised me the most is how much the group temperature can vary. I have my pstat set at 1.2 bar max and my group idles at 221F. I have learned that doing a large flush before the first shot out will bring the group down to a more normal range. I will then prepare the basket then do another smaller flush (to 205F) before starting the shot. This has given me very good results. However, I still feel I can improve and I think knowing precise shot temps would help me nail down a routine that will give me even better results. I decided to rent a Scace thermofilter to help me figure this out. This should be arriving any day and I think with the two together I can nail down a bulletproof routine. I'm looking forward to using this and will post results when I have them.

In MY particular regimen with Anita, I typically have 3 to 4 cappy's every morning (every 15-20 minutes) and I am the only drinker in the house. Still, I am a believer in over-flushing the machine and letting the grouphead cool the incoming shot water. However, the majority of hx users (at least from what I have gleaned over the years) simply flush-n-go. I would think this is the way our machines were intended to be used but the extensive flushing method is particularly well suited to producing consistent multiple shots.

Eric,
I was using a flush and go technique, but recently switched to your flush and wait approach. I typically make two doubles in a row...one for my wife and one for me. I flush to, say 195F, wait until the head temperature climbs to 198F and pull a shot. This works great. The problem is that after the first shot, the head is at about 200F. I hate to run a bunch more water to cool the head back down, so I've resorted to putting a wet cloth on the group head while I grind and prepare the next shot. This will bring the head temperature back down to about 197F, and a short wait gets it back to 198F for the second shot. This seems to work well, but I haven't checked the actual temperature behavior and don't know if the resulting shot temperature is as stable as for the first shot. Have you done any testing on this technique? Or, can you suggest a different approach to get the head temperature right for the second shot?

Thanks
curlyjim

Well, I have had access to a Scace the past two days and here are my initial findings. It turns out that the flush-and-go method is much more complicated than I had initially thought. The flush-and-wait method that eric recommends does indeed work well to give consistent temperature between shots. This does not work as well for me, though, as I have minimal time in the morning and this method requires several minutes between shots. To my initial frustration, I also discovered hitting a consistent brew temp using the flush-and-go method by flushing to a set temperature is literally impossible. The brew temp is greatly affected by the idle group temperature. Since the idle group temperature will be different between multiple shots, the final flush temperature will be different as well. I was able to determine by altering the flush end temp according to the idle group temp, I can get remarkable temperature consistency with the flush-and-go technique. I have made a chart to help with this.

Target Brew Temp 201F
Idle Group temp--Flush End Temp
200°F ----------------210°F
202°F ----------------209°F
204°F ----------------208°F
205°F ----------------207°F
206°F ----------------206°F
208°F ----------------205°F
210°F ----------------204°F
212°F ----------------203°F
215°F ----------------202°F
217°F ----------------201°F
223°F ----------------200°F



Brew temperature measurements were obtained with a Scace Thermofilter and a calibrated Fluke 54II meter. Measurements were verified at multiple pressurestat settings between 1.0bar and 1.3bar. The pressurestat setting does not appear to have an effect when using this chart. Recovery times between 0-20 seconds were tested with similar results. Higher recovery times result in a larger initial hump in the profile. Recovery time does not appear to be critical, however most measurements were obtained with a 10 second recovery time. To pull a shot hotter than 201°F, increase final flush temp by 1°F for each degree higher desired. To pull a shot cooler than 201°F, decrease final flush temp by 1.5°F for each degree lower desired. The group must be idling at or above targeted brew temp prior to beginning flush. Allow at least one minute between shots to obtain consistent results. These results were obtained on an Alex HX espresso machine and do not necessarily apply to other models.

Once again, these are still early results and I will be testing this further in the next few days.