How to use cheapo thermocouple?

Beginner and pro baristas share tips and tricks for making espresso.

#1: Post by randomperson »

In order to get more scientific about my flushing with my new La Valentina (which I need to do since for the life of me I cannot discern the end of the water dance -- seems way too subtle on my machine) I got a cheap thermocouple device. It's the one jim schulman recommended, I believe -- but for the life of me I can't find the thread about it! (If anyone knows how I can find it -- something like the "$10 solution for temp management" or such -- I'd be grateful)>

Anyway, I threaded this thing up the single spout, put in a little foil to keep it in place, and then ran some water through after an hour warmup. The problem is the water pours out really quickly and even with extra foil (like a cup shape) I can't get any variance in the reading -- it just seems to hang out at around 95 - 96 degrees C from one ounce to six ounces flushed. But if I plop it in a glass of water it seems to immediately register the changed temp.

Any ideas on what I am doing wrong? I didn't expect this cheapie to be intensely accurate -- but I did expect it to show some variance as the flush progressed. Yikes -- unless my machine is malfunctioning! (I don't think so!!)

Oh I'm at a .95 setting.

I love La Valentina!

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#2: Post by HB »

Jim's thread is linked among the FAQs and Favorites of this forum, The $10 Method for Temperature Tuning an HX Machine. Are you listening or looking for the end of the water dance? La Valentina was set to 1.0 bar for the video below. You can see the transition around the 25 second mark in this video:
  • Short idle period (< 3 minutes) after warm up flush (not shown). Result: 202.1F
    «missing video»
To make these transitions easier to see, allow 3-5 minutes between espressos. Note the video above demonstrates a very short rebound (AKA, "flush-n-go") to produce a flatter temperature profile, not the longer "humped profile" rebound technique discussed in the review:
Listen for the hissing of steam and gurgling of boiling water before locking in the portafilter. Continue drawing water for about five seconds after the stream has settled down, for around six ounces total. Depending on the blend and your taste preference, the recovery time after the cooling flush is somewhere between 15 seconds (puck surface temperature briefly peaks about one or two degrees Fahrenheit above target brew temperature) to 35 seconds (puck surface temperature peaks around four degrees above brew temperature).
Dan Kehn

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#3: Post by another_jim »

Test the meter in boiling water, it may be **really cheap**. The one I used was accurate, but only updated about twice a second.

I used to just fill up the pf with crumpled foil, this slowed things down to about 2 ounces in 10 to 15 seconds.
Jim Schulman

randomperson (original poster)

#4: Post by randomperson (original poster) »

Thanks for responding so quickly!

I looked everywhere for that article except in the FAQ/Favorites section. Bah!

Dan, I can pick out the transitions in your videos within a second -- I just can't do it live with my own machine! Gotta try some more.

And Jim -- I mix up all my Jims! -- I am using the very thermocouple you recommended, so it should work. I'm gonna crumple up some foil and see.

Thanks for all your help!

I trudge onward!
I love La Valentina!

randomperson (original poster)

#5: Post by randomperson (original poster) »

Oh one more thing, if you don't mind.

If you use the flush and rebound technique, do you flush down further than your target temp? If so, how many degrees (or seconds) further?

Similarly, if you use the flush and go technique, do you still flush down further than your target temp? I would assume you do, but for not as many degrees or seconds.

Any guidance you can provide will settle yet another quandary!
I love La Valentina!

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#6: Post by HB »

To keep things simple, I flush the same amount and vary the rebound time to taste. The review advocated the rebound technique since it's generally easier to catch the desired temperature on the way back up than on the way down. With the added clues provided by Eric's thermocouple adapter, the flush-n-go is my preferred technique for La Valentina. As your questions suggest, you are intentionally passing the brew temperature slightly and then letting the temperature return in the first case; in the second case, the very short rebound is really more of a pause to allow the HX to stabilize.

If you're having difficultly recognizing the transition point, I recommend measuring the flush amount instead as suggested in the Buyer's Guide to the Quickmill Vetrano:
If all this talk of listening to cooling flushes has your head spinning, below are Bob Yellin's keep-it-simple rules that work well:

1. If the machine has been idle for awhile, flush 6 ounces
2. Or, if the machine has been idle around three minutes, flush 2 ounces
3. Wait 30 seconds and start the extraction.

That's it!
You may have to adjust the rebound time in step 3 slightly given your pressurestat setting. My guess is around 20-25 seconds.
Dan Kehn

randomperson (original poster)

#7: Post by randomperson (original poster) »

Ahh, that's the ticket! Would simply flushing 6 ounces work even if it was the first shot of the day? I've been preparing my shot first, then flushing, then pulling. BobY (elsewhere, I believe) suggested pulling 6, then preparing the shot (in under 3 minutes, I presume!), then flushing another 2 ounces, then pulling. Would both techniques work equally well? And I assume if I wanted a cooler temp I should shorten the rebound or eliminate it altogether.

I wonder if I should lower the pressurestat. Mmmm. I thought .95 was pretty lowish. I don't want to unscrew her just yet -- she's too new (and so am I).

I PM'd erics about his upcoming modified thermocouple adaptor (the one with the three minute installation routine) -- I NEED his device!

Nonetheless, despite all my issues I do love the machine. I love her looks and the solid thwap as the heating element turns on and off. I love being able to leave her on most of the day. And my houseguests thought my shots were superb (they sucked, really -- after all, I'd only pulled about three shots or so last night before my debut with guests this morning --but cappas hide a multitude of sins!). It all felt very festive this morning -- and I've only had La Val for two days!
I love La Valentina!

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#8: Post by HB »

randomperson wrote:Ahh, that's the ticket! Would simply flushing 6 ounces work even if it was the first shot of the day? I've been preparing my shot first, then flushing, then pulling. BobY (elsewhere, I believe) suggested pulling 6, then preparing the shot (in under 3 minutes, I presume!), then flushing another 2 ounces, then pulling. Would both techniques work equally well?
I agree with Bob, a "warm up" flush prior to the actual brew temperature flush helps stabilize the group. You can see the consequences in this video where I overshot the flush and missed the target temperature by 1.5F even with the aid of a thermocouple readout. Without it, I could have been off by double that. All espresso machines that I've worked with are happier with a wake-up call before getting down to business (the GS3 being the sole exception).
  • Long delay (10 minutes). Result: 200.0F
    «missing video»
Trust me, three weeks from now you'll be giving instructions to others. The key is getting the extractions consistently correct so you'll be able to accurately judge temperature differences. With all this temperature hullabaloo, many forget that's the harder skill to master.
Dan Kehn


#9: Post by framey »

Nice hat Dan :D

randomperson (original poster)

#10: Post by randomperson (original poster) »

Thought I'd give a progress report.

This good news is that things actually seem to be coming together!!

For one thing, the "Lazy Broad's Flushing routine" seems to be working really well -- 6 oz flush (sometimes 5.5 for kicks) plus a 20-25 second rebound produces very good shots -- not Godlike, yet, but very very good. This is particularly interesting because as luck would have it my .1 gram scale died two days ago (probably because I spilled hot water on it one too many times as I turned on the hot water tap thinking it was my steam knob!) so I am having to dose by look and feel rather than by gram. So naturally there is some inconsistency! So I am particularly impressed by the quality of the shots absent my gram scale.

It also proves Dan's point about the relative forgiveness of these E61 machines vs single boiler ones in terms of dose and tamp.

It could also be my imagination but in my mind's eye I am starting to think I can hear the end of the flash -- but only if I cock my ear right next to the group head so that I can hear the sputter over the noise of the vibe pump. This could be my imagination, but we'll see!

If my ears are correct, it looks like a 5 minute idle needs a four ounce (total) flush (flash plus 10 count), vs a 10 minute idle and its 6 oz flush, vs 2oz for an under 3 minute idle time. Are my ears deceiving me or does this sound like it might make some sense?

I am also noticing that I can tell how a shot will taste simply by sniffing it -- the sour or bitter notes will dominate if the shot is poor, and if the shot is on the money the smell is simply roasty.

As for microfoam -- well it is truly an amazing thing, this machine! It steams forever, and the microfoam (when it comes together -- which is now most of the time) is simply gorgeous -- absolutely unachievable with my Gaggia. And I love how it's ready to go all the time! I am purging the wand until the light goes on, then waiting until the pstat goes up to the top of the cycle, as Dan suggested. With this setup, I can steam until the cows come home! (I am in Vermont after all!)

Now, the pstat -- seems to hang out at around .9 but tops out at 1 and bottoms out at around .6 -- all of this within the "red section" of the gauge, so that would seem to be the appropriate setting. I had asked for a setting of .95 so I assume this range is correct. Does it seem ok to you all???

Will keep you posted -- am still seeking best possible shots, so clearly have some learning to do -- but I am pleased by my progress so far and have only had La Valentina since last Friday -- just 4 days or so to get this far!

Do let me know about my simplified flush routine -- does it seem OK to you all? (Goal temp is around 198-199).

Oh and as for the cheapie thermocouple -- I've abandoned it, as it doesn't seem to register any temp changes! Must be the nature of how it's placed in the basket!

Thanks again for all your help!
I love La Valentina!