Part 3

Some of the data from my bench testing was gathered before cleaning my machine with Urnex and some afterwards, with consistent results. In this part, I will show some date collected to test the ease of setting up common shot-pulling routines on an E-61 HX machine. Without boring readers with all the data on all the various tasks that I tested, these two are of prime interest to E-61 HX users:

1. An initial flush after an extended rest period to ready the machine for pulling shots (eliminating the "water dance" method).
2. Set up of a routine that will produce consistent temperatures, shot after shot by observing the time between shots.

For the data shown below, I should note, that in normal use, after a shot is pulled, more HX water is used to clean the shower screen, etc., so one does not normally run consecutive shots as I did in this test. But the purpose in this specific test was to demonstrate that I could quickly get consistency and accurate results using the TTD, rather than trying to exactly duplicate my normal routine. Later, I did indeed, easily manage to zero in on a flushing routine that fits my specific espresso-making habits.

In the examples below, I picked 199 deg F as a general target shot temperature. This temperature produces a desirable shot from certain of my beans and is a good average between 203 F and 195 F, the range I am likely to use in practice. The dip seen between shots in the first graph is the removal of the pf from the group head to relieve pressure, dump out water and for other reasons.

The first graph shows an initial flush after about 20 minutes of machine rest, from about 209 deg F down to about 196 F. That took one minute (5.4 oz.) through the device and was my pre-determined flush to set up a 199 deg F shot temperature after a 3-minute wait. The next graph shows the 25-second shot, three minutes later.

The next graphs show the use of time between the shots to control consistency. The two graphs show the first and third shots in a series. Very good consistency is quickly, accurately and easily achieved.

The final installment will compare this device to the use of another pf with an embedded TC using both a sponge to simulate the flow and coffee, in the basket.

BobY

The two dips seen below are due to pf removal from the group head between the flush (beginning of the chart) and the 25-second shot (end of the chart).





First and third shots of a long series of consistent-temperature shots.

Bob,

Just to make sure I fully understand your usage of the Portazilla (my nick name, and I hereby place it in the public domain). You use it to develop a flush chart that will be tied to idle time. Like my Giotto flush chart?

It's one of a number of uses for it.

-Greg

Abe Carmeli wrote:Bob,

Just to make sure I fully understand your usage of the Portazilla (my nick name, and I hereby place it in the public domain). You use it to develop a flush chart that will be tied to idle time. Like my Giotto flush chart?

If you're asking about my personal usage, my goal for now is just to bench test this device. Ultimately I will use it for multiple purposes including the development of a routine where I can get reasonably close to predicting what the temps will be without the use of any charts. That will be one of my personal goals. What others do with it is up to them.

BobY

BobY wrote:It could be that a grain of coffee or something else was freed up from the filter and drifted down to the orifice.

the filter is a 40 micron sintered bronze filter; no coffee grains should be finding their way to the south end at all.

other possibilities: swarf from drilling the orifice, and stray filaments of teflon tape.

i'm really interested in nailing down what's happening here.


--barry "if the filter ain't filtering, i wanna know about it"

barry wrote:

the filter is a 40 micron sintered bronze filter; no coffee grains should be finding their way to the south end at all.

other possibilities: swarf from drilling the orifice, and stray filaments of teflon tape.

i'm really interested in nailing down what's happening here.


--barry "if the filter ain't filtering, i wanna know about it"

Yeah, I mentioned that it might be teflon tape, but I didn't mention swarf. And I like to say swarf too. Swarf Swarf Swarf Swarf Swarf Swarf Swarf!

-Greg "also in knowing the root cause" Scace

another_jim wrote:
Interesting. After reading our various "how to adjust vibe pump posts," some people complained when the found their brew pressures were 1/2 to 1 bar below their blind pressures. I guess this is a characteristic of OPVs rather than the pumps they regulate.

If the drop from blind to flow would be constant across all machines, shot flow rates, and OPVs, it would be no sweat. Just set it by the blind filter and everyone will get the same result. However, if that creates different actual brewing pressure for different machines and shots, then setting pressure with metered flow from the group also become very desirable.

For Greg Scace - great display of a lot of ingenuity in your temperature measuring device. As far as measuring pressure is concerned, a neat way to do this would be to install a 1/8" NPT sampling adaptor (I believe Parker is the source) with plug and corresponding "needle" adaptor which slides through a self sealing neoprene plug. I have some left over from my engine engineering days in the event you want to try them. Understand your concerns about the volume matter.

For Another_Jim - thanks for your many thoughtful contributions to the coffee sites. Checking pressure (intentional omission of setting/adjusting) while having a metered flow is, IMO, essential. The difference in pressure measurements is due to the delta P experienced by the water as it flows through the "system" wherein a large contributor to this pressure drop is the three-way valve.

Eric S.l

gscace wrote:Yeah, I mentioned that it might be teflon tape, but I didn't mention swarf. And I like to say swarf too. Swarf Swarf Swarf Swarf Swarf Swarf Swarf!

-Greg "also in knowing the root cause" Scace

For those of you who, like me, don't (didn't) know what "swarf" is...I looked it up:

Swarf refers to the mixture of broken-off abrasive, metal filings, and lubricating liquid that results during the sharpening process. Abrasive breaks off of the sharpening media, such as a grinding wheel, waterstone, or sandpaper. The metal filings are the "scratched-off" material from the tool being sharpened. The lubricating liquid could be water or a cutting oil.

Bob "now I know what swarf is" Y

BobY wrote:Swarf refers to the mixture of broken-off abrasive, metal filings, and lubricating liquid that results during the sharpening process. Abrasive breaks off of the sharpening media, such as a grinding wheel, waterstone, or sandpaper. The metal filings are the "scratched-off" material from the tool being sharpened. The lubricating liquid could be water or a cutting oil.

it's the slivers of brass/steel/aluminum that end up in my foot when i walk around the basement w/o shoes on.


--barry "doh dee doh dee doh d'OWW!"