The $10 Method for Temperature Tuning an HX Machine

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another_jim
Team HB

#1: Post by another_jim »

waxnyc wrote:Yet if mine has been idle for a while and I turn on the pump, water splatters everywhere for about 4 ozs. finally calming down into a vertical stream.
akin wrote:Jim, I do not know if Mark's Livia was modded or not but my Bezzera's brewhead gets up to 102 C after 40 minutes idle - adjusted to cycle btw. 0.9-1.1 bar - so that one can severely burn himself. Reading at CoffeeGeek I also thought that the Bezzera has a cold nose but this is not what I measured.
If you open the top and leave it like that the group will run at least 6C cooler. May be owners were doing the measurements with a naked Bezzera.
Sure contradicts what I heard; but seeing is always better than hearsay.

If you read the posts here, you'll get the impression that temperature measurements require a major outlay. This is true if you want temperature graphs of the whole shot using procedures that are repeatable across different brands. It is not true for measuring average shot temperatures and determining the required flush amount. So back by popular demand:

The $10 Method for Temperature Tuning an HX Machine

1. Make 4 or 5 shots in a row, timing yourself from the moment you turn off the pump on the first shot (to eliminate the extras the first shot requires) to when you turn off the pump on the last one. Work out your average pace.
2. Determine the temperature you want to make shots at -- you'll be more or less stuck with this when making lots of shots so pick something on the middle 93C or 200F for instance.
3. Buy a cheap thermocouple; my pick is:
http://shop.store.yahoo.com/techbuys2003/tm-125.html for $10 a pop.
Take the basket out of your PF, snake the thermocouple lead up the spout, and fix it in there with some silver foil. For this exercise, flow rate is irrelevant.
4. With the measuring PF mounted, flush the group till you hit your desired temperature.
5. Run 3 - 4 ounces at a time at your normal shot making pace, noting the average shot temperature (this meter is so slow, just take that it ends up at near the end of the pull). The extra volume compensates for puck absorption and the cleaning flush. Timing is unimportant here; you're looking to get the right amount of cold water into the HX so you can see how well it recovers by the next time you make a shot.
6. Tweak your pstat up if the temperatures fell during the series, down if they rose.
7. Repeat 5 and 6 until the pstat is set right.
8. Let the machine idle for an hour.
9. Only now determine the flush times or volumes by measuring the flush temperature again-- the "number of seconds from the time it stops boiling" technique is the most flexible.

Some HX machines are designed to run below 1 bar; and if your shot making pace is slow, you may need to go waaay down on the pstat to get stable temperatures for the series. In this case you may have to compromise to get good steaming. However, on the Livia, even 0.7 to 0.9 bar should give excellent steaming times.


Split from How can I stop worrying and learn to love Livia? by moderator...