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Gaggia Evolution - Not bad!  made me eat my words!
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Discussions > Espresso > Machines > Gaggia Evolution...  
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AndyPanda
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AndyPanda
Joined: 12 Jul 2010
Posts: 769
Location: San Francisco Bay Area
Expertise: I love coffee

Espresso: Olympia Cremina, Various...
Grinder: Mazzer Major, Fiorenzato,...
Vac Pot: vintage Corey
Drip: AeroPress
Roaster: BreadMachine/HeatGun
Posted Sat Sep 4, 2010, 12:21pm
Subject: Re: Gaggia Evolution - Not bad!  made me eat my words!
 

Well I spent some time with a TC - lots of surprises, surprise for me at least.

I couldn't get anything that was very useful with the TC inside the boiler - I threaded it through the SPV and tried the tip in various places (in the tube, in the main boiler, higher, lower etc).  I was surprised to find that the water temp actually goes up way faster and higher than the temp at the thermostat switch on the outside (probably because that thermometer is much slower to react than the faster TC inside).  I had expected that the probe on aluminum outside would get hot and then gradually the TC inside would come up to temp - but what I saw was way more erratic with the TC inside swinging much higher than the probe on the outside.  I'd probably do better with two TCs (so they both read fast instead of having the one slower thermometer) - as it is I have the cheap digital probe on the outside and that thermometer seems to take several seconds to register a temp change from comparisons with the TC also on the outside. The TC would show the temp changes much faster than the metal probe thermometer (because of the metal mass of the probe?).  So I'm not exactly sure what to make of, or how to use, the info I got with the TC inside.  I was surprised to see the water temp go above 212F - but I guess that's because of the pressure - when I released the pressure I'd get a burst of steam and the temp would drop.  measuring the water in the boiler with the steam valve removed completely (no pressure) it got to exactly 212 and never higher (as expected).   But I couldn't figure out how to use the info to time a shot since the TC was frequently reporting higher than 212F inside. With the power off the two thermometers would quickly stabilize to read the same (or close) - but just a second on the pump would cause the TC inside to swing wildly - I'm not sure I trust what it was telling me - and I wonder if having the length of wire and woven insulation being submerged in hot water affects how it reads. (it's a K-type)

So after I tired myself out trying to make any sense of all that.  I removed the TC, put the SPV back as it was and spent some time with the cut down styrofoam cup holding the TC under the shower screen.  Here's what I learned:  Right after you pull a shot, you need to wait longer than I expected before you can safely pull another shot. The water temp at the shower screen was swinging (quickly) from extremes of 182 to 211 if measured very soon after pulling a shot. (refilling the boiler with cold water)

What I found (for me, with my probe thermometer on the brew thermostat mount) - If I wait until the boiler temp is dropping very slowly (217 for 10 sec -216.5 10 sec etc.) and then start the shot just as it hits 215.0F, I get 197F at the shower screen every time.  And it stays somewhat stable for a single shot (yeah I know - who uses the single basket besides me? I actually get very good singles) and less stable for a double or double ristretto.   If the temp is falling at a faster rate and I start the pull at the same temp I get a much cooler (and unpredictable) temp at the shower screen.

I am able to get to that stable temp (dropping very slowly) pretty quickly after a shot by not letting it do it's normal wide swing with the thermostat.  I just kick the steam switch for 4 seconds before it gets cool enough for the brew thermostat to kick in.  If the temp is dropping quickly, I kick the heat on for four seconds and keep the swing in a narrower band (say between 215F and 220F). If I do that twice after pulling a shot then I'm back to the temp barely dropping and I feel safe to pull another shot and get the temp I'm expecting at the shower screen.
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Kristi
Senior Member
Kristi
Joined: 6 Oct 2005
Posts: 2,286
Location: Boston
Expertise: I love coffee

Espresso: Gaggia Evo w silvia wand
Grinder: Macap M4 mod to d&s-less
Roaster: (Jeff at Redbirdcoffee)
Posted Sat Sep 4, 2010, 1:21pm
Subject: Re: Gaggia Evolution - Not bad!  made me eat my words!
 

LOL - okay...  I'm confused!  LOL !!!

Sometimes when you were inside the boiler you would get higher than 212 if the tip was in the steam at the top of the boiler, and drop quickly when you bleed the steam out and there's no steam layer in there (which doesn't last very long.  If it was actually down in the water I have no explanation as the water temp doesn't vary that much at the pressure in a boiler.

Styrofoam is inaccurate - get some 30ga K tc wire on fleabay and make your own TC's by baring 1/4" on the end and twisting the wires together on the measuring tip.  Then do OTL testing.  Just my opinion.

Yes, the speed of the meter matters a lot in this - that's why folks with these nice big machines normally go toward fluke meters, and I pounced on the Omega when I had a chance.  How is the Sweet Maria's meter for speed?

For the moment I have stopped turning the meter on, and simply warm it up for 20 min, and then prep and by about 22 min I am lock/load/pull.  I have no idea where the temp is, but I'm getting gloppy crema (I think Mark Prince calls this Guinness effect)(never seen a Guinness pulled draft)(darn), and a yummy espresso.  Not much chocolate, but yummy.

Okay, that one just now had some chocolate...

I took the twin spigot off the pf at Cathi's suggestion and left it off.  Was watching the crema coming out and wishing I had a bottomless pf as I was seeing definite tiger striping.  Good beans.  Doesn't blond until close to 40 sec.  I really love this Mason jar thing where I bring it out of the freezer in 8oz batches to use...

Back to meters:  I do not at all think one has to get a Fluke or other expensive meter.  Mine would have cost 150-200, but I got it on fleabay for 35 - either it was hot or he didn't know what he had. - only reason I have it!.  I seem to recall looking at fleabay and seeing a bunch that would probably be quite good enough for $50 or less.  The S.M. you got may be a good example.

However, looking at 2 or 3 meters at once while doing a pull is impossible for me.  I would need a multi input grapher and even then, with these little machines, where things change sooo fast, I probably wouldn't understand what to do.  Kudos to you for your efforts!!!!!  It's fun and educational to read!!!

EDIT: comment on gloppy crema - way back when I had 2 Mazzer Majors (fleabay) and 2 Macap MC4 stepped (new/closeout Jim at 1st Line), I noticed that, consistently, the pulls ground with the Macaps were more billowy/gloppy than the ones ground on the Mazzers.  I don't think I've seen anyone else say that.

 
#--> I recommend Eric Svendson's adapter and thermometer for E61s (also Silvia) : easy surfing!
# My photo albums have moved to     http://picasaweb.google.com/krislema2
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AndyPanda
Senior Member
AndyPanda
Joined: 12 Jul 2010
Posts: 769
Location: San Francisco Bay Area
Expertise: I love coffee

Espresso: Olympia Cremina, Various...
Grinder: Mazzer Major, Fiorenzato,...
Vac Pot: vintage Corey
Drip: AeroPress
Roaster: BreadMachine/HeatGun
Posted Sat Sep 4, 2010, 8:42pm
Subject: Re: Gaggia Evolution - Not bad!  made me eat my words!
 

Kristi Said:

LOL - okay...  I'm confused!  LOL !!!

Sometimes when you were inside the boiler you would get higher than 212

Posted September 4, 2010 link

You think you're confused? --- hehe - you ought to be here looking at what I was seeing - it's got me scratching my head.  But some things I "sort of" understand - Are you familiar with how water boils at less than 212F if it is at high altitude (low pressure)?  Likewise if water is under higher pressure than sea level it will boil at a higher temp than 212F (which is why they make pressure cookers to hold the pressure and allow water to get hotter than 212F so it can cook things faster - in fact, just a tight fitting lid on a pot is enough to raise the temp a little above 212F as the pressure builds enough to raise the lid).

To clarify what I was seeing ... if I take the steam valve off the top of the boiler and leave it off (so no pressure can build up) and just dangle the TC in through the open hole - it won't read any hoter than 212F (this is as expected) - but when I thread the TC through the SPV vavle and seal it and bolt the steam valve back to the top of the boiler with the TC dangling inside, in the water - it sometimes reads higher than 212F (like 5-10 seconds after the boiler has reached the high temp so the ready light comes on) until you open the steam valve to release the pressure or start the pump - that forces the water out the group valve with an initial puff of steam.  I think I've read posts where people believed this was the screen being so hot it flash boiled the water when it hit the screen - I am now believing that what is actually happening is: the superheated, liquid water escapes the group valve and sees normal sea level air pressure and it flash boils because it is giving up the extra heat converting to steam as it comes to normal pressure with that first spurt out the valve.

Other threads and tests iwth pressure gauges have shown that the group valve holds a certain amount of steam pressure (depending on which thread you believe, anywhere from 2 bars to 6 bars). And I've seen that if you heat the boiler for steaming but don't open the steam valve, you get a little sneeze of steam out the group valve (on these cheaper gaggias without a solonoid valve) as the pressure in the boiler reaches the level that can just open that group valve.

So I wasn't measuring steam temp and seeing it change as I "bled the steam out" ... the probe was in liquid water that was hotter than 212F because it was under pressure - and when I released the pressure that superheated water quickly turned to steam which dropped the temp back down (that's over simplistic but it is one of the unusual things water does when it changes from liquid to gas, it cools and that is what limits water temp to 212F when it is at normal sea level pressure, if you try to get it hotter the extra energy simply goes to producing more and more steam and cannot raise the temp of the water - (water does other strange things when it freezes and changes to solid).  

It sort of makes sense (now that I think about it) but it wasn't at all what I expected to see when I first thought of threading the TC in there.

Kristi Said:

How is the Sweet Maria's meter for speed?

Posted September 4, 2010 link

Pretty fast - seems nearly instant - though the insulation on the wire is quite thick.
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Kristi
Senior Member
Kristi
Joined: 6 Oct 2005
Posts: 2,286
Location: Boston
Expertise: I love coffee

Espresso: Gaggia Evo w silvia wand
Grinder: Macap M4 mod to d&s-less
Roaster: (Jeff at Redbirdcoffee)
Posted Sun Sep 5, 2010, 10:18am
Subject: Re: Gaggia Evolution - Not bad!  made me eat my words!
 

my bad - I knew it went up - just didn't realize how fast it went up...
Click Here (www.engineeringtoolbox.com)

Get some 30ga tc k wire and use it on the SM meter!  (assuming it's a "K" meter...)

 
#--> I recommend Eric Svendson's adapter and thermometer for E61s (also Silvia) : easy surfing!
# My photo albums have moved to     http://picasaweb.google.com/krislema2
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AndyPanda
Senior Member
AndyPanda
Joined: 12 Jul 2010
Posts: 769
Location: San Francisco Bay Area
Expertise: I love coffee

Espresso: Olympia Cremina, Various...
Grinder: Mazzer Major, Fiorenzato,...
Vac Pot: vintage Corey
Drip: AeroPress
Roaster: BreadMachine/HeatGun
Posted Mon Sep 13, 2010, 8:08am
Subject: Re: Gaggia Evolution - Not bad!  made me eat my words!
 

Hey Kristi,
If you're still  monitoring this thread ... I discovered something interesting with the digital thermometer I was using (I think you bought the same one?).

It responds a little slowly because of all that metal in the probe (it was meant to be stabbed into a roast or a turkey).   I was curious and pretty sure that there might be an ordinary TC down inside that metal probe (it's just a hollow tube) - and there is.  I simply popped the top off the thermometer (like you would to change the battery) and pulled the TC wire out of the metal probe.  There was a small dab of glue holding the wire at the top of the probe - I just scraped that off with a small screwdriver and then the wire was free to come out (I bought another one and the second one didn't have any glue there - the wire just pulled out easily).

Then I cut off the probe so I was left with just the small plastic housing and put the face back on the housing with the wire coming out the hole where the probe was.   Very cool little TC  for $10 (dunno if it's K type but I think it is).  

I drilled a tiny hole in the face of the gaggia and fished the TC through and mounted the Thermo on the front (nice 45 degree angle for easy reading) and now I have a very attractive looking digital readout that responds very fast.    It worked pretty well just by loosening the screw that clamps the thermal fuse on the top and wedging the TC bead underneath that fuse and tightening - but I ended up sticking the TC bead to the middle of the flat part of the boiler with a dab of epoxy putty (no glue between the TC and the boiler - just a dab of putty to hold it against the metal). I imagine a small square of duct tape would have worked.

I did many experiments with another TC over the rim of the portafilter as you suggested.  I pretty quickly found a surfing technique that was repeatable to give me the same brew temp each time - still not sure where the TC probe should be when going over the rim - I just had it resting on top of the puck.  I'll have to read some more of those posts you gave me links to.  I think the way Gaggia keeps the grouphead so hot, the showerhead must be helping hold the brew water temp during the pull - I was surprised at how stable the brew temp stayed throughout the pull.    I worried that the puck was pressing the TC against the showerhead and I might be reading the temp of the metal rather than the water - so I tried poking the TC into the puck and still the temp stayed pretty stable throughout the pull without dropping as drastically as everyone says happens with Gaggia.

If you're curious, I'll try to take a picture of how I mounted the thermometer.  Best $10 I ever spent - now if only I could find a nice looking, small pressure gauge to mount next to it - and a stopwatch.
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Kristi
Senior Member
Kristi
Joined: 6 Oct 2005
Posts: 2,286
Location: Boston
Expertise: I love coffee

Espresso: Gaggia Evo w silvia wand
Grinder: Macap M4 mod to d&s-less
Roaster: (Jeff at Redbirdcoffee)
Posted Fri Sep 17, 2010, 9:49am
Subject: Re: Gaggia Evolution - Not bad!  made me eat my words!
 

I do still look in on it - probably will till I die or Mark gets smart and bans me  LOL.

Long time ago I had one of those thermometer on a probe things - glued it to the end of an E61 nose bolt for a while, and then, yes, did remove the tc from the tube - easy as long as they don't use much glue.  But my meter of that variety was too slow so it eventually hit the circular file.  There's actually an old thread in CG describing what you discovered.  A Gaggia with gauges on the front!  Neat!!!  Go for it!  At the moment, I have no meters/tcs attached, and just making spresso.  

I did discover one little thing that would apply to all machines - if I lock and load, and then leave it there, for even as little as 10 secs, before turning on the pump, the pull is MUCH faster - apparently the coffee grounds warm up and react differently when the water hits them - makes for a watery brew - no sink shots, though - just a note to self on wall by machine! :D

 
#--> I recommend Eric Svendson's adapter and thermometer for E61s (also Silvia) : easy surfing!
# My photo albums have moved to     http://picasaweb.google.com/krislema2
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Kristi
Senior Member
Kristi
Joined: 6 Oct 2005
Posts: 2,286
Location: Boston
Expertise: I love coffee

Espresso: Gaggia Evo w silvia wand
Grinder: Macap M4 mod to d&s-less
Roaster: (Jeff at Redbirdcoffee)
Posted Sun Oct 3, 2010, 11:56am
Subject: Re: Gaggia Evolution - Not bad!  made me eat my words!
 

I have experimented a bit with a bunch of techniques but I seem to easily get a delicious soft espresso with a hint of chocolate (RedBird espresso beans) by starting the pump and turning on the steam switch at the same time, and turning off the steam switch at 10 seconds.  I see no reason why this wouldn't help any small boiler, non-HX, non-3-way machine.

I do find it helps to monitor the BOILER temp (I have a tc taped to the front side of the boiler) - temp normally bounces from 210F to 228F or so.  I check the BOILER temp when I come to the machine.  For 218 to 224, this method seems to work perfectly.  Above 224, I would tend to delay the 10 sec steam-switch-on by a couple of seconds.  If below 218, I would probably start the 10 sec steam-switch-on cycle 2 or 3 seconds before I start the pump.

Again, I tune my technique for taste!  While I realize that the temp at the puck can be held more constant by flipping the steam switch on and off at varied rates, my approach here very easily gives me a taste that makes me want to brew another.  It's also a pretty simple method that any noob or non OCD barista can do.  

If you don't have a tc and meter, you can still do it without checking anything, and I have experienced tasty results.  If you really want to sit there and watch the light for 3 minutes, wait until it goes out (heater on), then wait until it goes on (heater off), then wait 20 seconds and start your pull and steam cycle.  

I do not put the loaded/tamped basket into the pf holder, and lock and load until a second before I start the pump switch as I have found that the heat from the brew head and pre-heated pf holder radically affect the pull in a negative way - much faster and much more watery.

My pulls range from 25-35 secs or so depending on the age of the beans and amount of grounds - I stop the pull based on what it looks like - turning blond, or turning watery.

Above all, whatever approach you take, enjoy your tasty brew!!!

 
#--> I recommend Eric Svendson's adapter and thermometer for E61s (also Silvia) : easy surfing!
# My photo albums have moved to     http://picasaweb.google.com/krislema2
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AndyPanda
Senior Member
AndyPanda
Joined: 12 Jul 2010
Posts: 769
Location: San Francisco Bay Area
Expertise: I love coffee

Espresso: Olympia Cremina, Various...
Grinder: Mazzer Major, Fiorenzato,...
Vac Pot: vintage Corey
Drip: AeroPress
Roaster: BreadMachine/HeatGun
Posted Sun Oct 3, 2010, 3:42pm
Subject: Re: Gaggia Evolution - Not bad!  made me eat my words!
 

There is no arguing with taste! If it tastes good then it must be working.

I don't know where people come up with the specific temperatures that it is "supposed to be".  Yeah, I've read the paper by Dr. Illy.  But everyone measures differently and everyone is using different coffee and techniques .... and they all have different tastes - and taste is all that really matters.

The way I'm measuring temps - if I were to do what is working best for you (starting steam switch with pump and leaving it on for 10 seconds)  I would see the brew temp drop about 5-6 degrees F over the first 6 seconds and then rise from there to the end of the shot - which would be very high (like 210F) by the end of the shot.  So in terms of numbers it doesn't follow what people are trying to get with their PIDs - but in terms of taste, it is working for you - so that's all that matters. And it's so much easier to do too.

Anyway ... Mark predicted that temp profiling would be the next big thing - sounds like you found the temp profile that works for your tastes with RedBird.  I'm having better luck for my tastes using a much different timing of the steam switch that holds the temp pretty stable through the shot - but my pulls are probably very different from yours - the steam switch to brew temp timing varies depending on how fast the shot is pulling.

As far as working for different type machines - I experimented a bunch today with a SS boiler machine with the heater inside.  They are extremely different in how they behave from the Gaggia with the heater on the outside. (mainly because the water inside is hotter than the outside of the boiler where the TC probe mounts - on a Gaggia the outside of the boiler is hotter than the water inside).   So the technique that worked best for me is a bit different on the SS boiler than what works for me on the Gaggia.
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