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Gaggia classic pre infusion (steam valve open)
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Discussions > Espresso > Q and A > Gaggia classic...  
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Mrparapluie
Senior Member
Mrparapluie
Joined: 10 Sep 2013
Posts: 19
Location: Quebec
Expertise: I like coffee

Espresso: Gaggia Classic
Grinder: Ascaso iSteel 1 (54 flat...
Posted Mon Jan 13, 2014, 10:46am
Subject: Gaggia classic pre infusion (steam valve open)
 

Hello !

I would like to know who have already try this method. It consist to open the steam wand before the brew process to pre infuse the puck with low pressure flow.

This is what i do :

Hit the steam button for 5 sec (heating a little bit much because we loose water during the pre infusion)
Load the portafilter
Lock the portafilter
Open the steam valve one quarter
Hit the brew button with the valve open
Pre infuse for 5/6 second ( at this point normaly the flow begin at 6-7 sec without the valve open but if i let the valve open i have no coffee before like 10 sec)
Close the steam valve slowly (after 5/6 sec), the pump is now pushing more and more to finally have the normal pressure
Let the shot finish, usualy the perfect time for this kind of coffee is 26/28 sec.

I taste it. The cup was great and everything seem seems balanced. I have to play with the method a little bit to learn everything but im verry satisfied with the shot quality !

Tell me your feedback with this method of pre infusion !
How many bar can i reach with the valve open ?
Is this safe for the pump ?
Do i have to grind finer because i pre infuse the puck ?

I hope we could have a nice discussion about that my friend :)

(Sorry for my english by the way :S )
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calblacksmith
Moderator
calblacksmith
Joined: 25 Nov 2007
Posts: 7,858
Location: Riverside, Ca, U.S.A.
Expertise: I live coffee

Espresso: ECM Vene. A1, La Cimbali M32
Grinder: Azkoyen Capriccio, Major
Vac Pot: 40s era Silex
Drip: Msl. Com. brewers
Roaster: gave it a try, decided no
Posted Mon Jan 13, 2014, 11:46am
Subject: Re: Gaggia classic pre infusion (steam valve open)
 

Mrparapluie Said:

Hello !

Posted January 13, 2014 link

HI :D

Mrparapluie Said:

I would like to know who have already try this method. It consist to open the steam wand before the brew process to pre infuse the puck with low pressure flow.

This is what i do :

Hit the steam button for 5 sec (heating a little bit much because we loose water during the pre infusion)
Load the portafilter
Lock the portafilter
Open the steam valve one quarter
Hit the brew button with the valve open
Pre infuse for 5/6 second ( at this point normaly the flow begin at 6-7 sec without the valve open but if i let the valve open i have no coffee before like 10 sec)
Close the steam valve slowly (after 5/6 sec), the pump is now pushing more and more to finally have the normal pressure
Let the shot finish, usualy the perfect time for this kind of coffee is 26/28 sec.

I taste it. The cup was great and everything seem seems balanced. I have to play with the method a little bit to learn everything but im verry satisfied with the shot quality !

Tell me your feedback with this method of pre infusion !
How many bar can i reach with the valve open ?

Posted January 13, 2014 link

With the steam wand open, you are allowing the pressure to vent so it would be low, I guess it would be in relation to how open the valve is.


Mrparapluie Said:

Is this safe for the pump ?

Posted January 13, 2014 link

I don't see how it will hurt the pump.

Mrparapluie Said:

Do i have to grind finer because i pre infuse the puck ?

Posted January 13, 2014 link

No, you grind the same.

Mrparapluie Said:

I hope we could have a nice discussion about that my friend :)

(Sorry for my english by the way :S )

Posted January 13, 2014 link

While I suppose you could do this, I, personally, don't see any value in it.

By turning the heater on, you bring your brew temp too high, there is always a new flow of water into the boiler when brewing and the manufacturer took that into account when they designed the machine. By turning the steam switch on, all you are doing is making the water hotter, you are not adding water to the boiler, it is already full of water an it can hold no more.

You will loose water from the boiler in the form of steam. A SBDU machine has a small enough boiler to begin with and letting water out of the boiler before brewing, only makes this worse.

Some people put a dimmer on the pump to try to slow it down, I feel a better way is with a circuit that changes the frequency rather than lowering the voltage as when you lower the voltage, it causes the pump to draw more power and that is a bad thing for the windings in the pump, they will over heat and burn out sooner. By changing the frequency, the pump will pump fewer times a second but while drawing the proper current so it does not over heat, this would have the affect of lowering the pressure in the system when brewing.

 
In real life, my name is
Wayne P.
Anything I post is personal opinion and is only worth as much as anyone else's personal opinion. YMMV!

Feed the newbs, starve the trolls and above all enjoy what you drink!
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Mrparapluie
Senior Member
Mrparapluie
Joined: 10 Sep 2013
Posts: 19
Location: Quebec
Expertise: I like coffee

Espresso: Gaggia Classic
Grinder: Ascaso iSteel 1 (54 flat...
Posted Mon Jan 13, 2014, 3:39pm
Subject: Re: Gaggia classic pre infusion (steam valve open)
 

thank you calblacksmith !

I have test today several shot with and without this pre infusion technique. I also test it with a friend and with two kind of coffee..

The shot with pre infusion was more complex and we have found some cereal taste who was awesome ! The time was 26s for 2oz.

The shot without the pre infusion was little bit sour, because the extraction time was 20s for 2oz (same coffee, same grind and tamping routine). The cereal taste was not there and the overall was "ok" but not like the first one. Interesting to see so much change between the first and the second one !

I don't need to tweak my pump to make it "profiling" cause i know the pump will get hurt. I think this pre infusion method is awesome and i will continue that way :)
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Frost
Senior Member
Frost
Joined: 26 Jul 2007
Posts: 2,099
Location: Sierra
Expertise: I love coffee

Espresso: Isomac Venus
Grinder: Lelit PL53
Roaster: Poppery I w/variac, MET, BT
Posted Mon Jan 13, 2014, 10:40pm
Subject: Re: Gaggia classic pre infusion (steam valve open)
 

The vibe pump 'motor' is essentially a solenoid coil and diode; there is no issue of drawing more current or overheating at lower voltages like a motor winding. This method is not so effective at the much lower flow/pressure range for pre-infusion though. The pump behavior becomes erratic and/or stalls at the very low voltages required. It works well in the range of around 6-10 Bar.

The issue using the steam wand is as Wayne mentioned; You are bleeding your precious 3.5 oz of boiler water and increasing temperature drop on the Gaggia during the shot, and it's hard to know what you are doing without a pressure gauge installed.
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calblacksmith
Moderator
calblacksmith
Joined: 25 Nov 2007
Posts: 7,858
Location: Riverside, Ca, U.S.A.
Expertise: I live coffee

Espresso: ECM Vene. A1, La Cimbali M32
Grinder: Azkoyen Capriccio, Major
Vac Pot: 40s era Silex
Drip: Msl. Com. brewers
Roaster: gave it a try, decided no
Posted Tue Jan 14, 2014, 7:13am
Subject: Re: Gaggia classic pre infusion (steam valve open)
 

Agreed the pump is little more than a coil, similar to a door bell coil, it is cycled on and off (AC voltage) and thus pulses the connecting linkage to the diaphram causing the water to move through the pump space and the check valves keep the water flowing in one direction. A lower voltage would cause the action of the linkage to move less per pulse and thus move less water, yep, it will not draw more current but a circuit that varies the CPS would be more effective than lowering the voltage, and would be much more "accurate" in the reduced flow as the coil would be operating at full magnetic flux and the linkage would be making the full stroke, just fewer times a second. YMMV :D

 
In real life, my name is
Wayne P.
Anything I post is personal opinion and is only worth as much as anyone else's personal opinion. YMMV!

Feed the newbs, starve the trolls and above all enjoy what you drink!
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brianl
Senior Member


Joined: 1 Dec 2012
Posts: 491
Location: Chicago IL
Expertise: I love coffee

Espresso: Quick Mill Vetrano DB
Grinder: HG One, OE Lido 2, Baratza...
Drip: Chemex/V60
Roaster: Behmor 1600
Posted Tue Jan 14, 2014, 7:45am
Subject: Re: Gaggia classic pre infusion (steam valve open)
 

Mrparapluie Said:

thank you calblacksmith !

I have test today several shot with and without this pre infusion technique. I also test it with a friend and with two kind of coffee..

The shot with pre infusion was more complex and we have found some cereal taste who was awesome ! The time was 26s for 2oz.

The shot without the pre infusion was little bit sour, because the extraction time was 20s for 2oz (same coffee, same grind and tamping routine). The cereal taste was not there and the overall was "ok" but not like the first one. Interesting to see so much change between the first and the second one !

I don't need to tweak my pump to make it "profiling" cause i know the pump will get hurt. I think this pre infusion method is awesome and i will continue that way :)

Posted January 13, 2014 link

Id be careful analyzing your results like that. If you pull the shots back to back, you will get fluxuations in temperature and the later shots usually taste better as all the parts have been heated with hot water. I've done what you said and noticed exactly no changes. Interesting to hear your results. I use a PID though, so I don't get huge temperature fluxuations.
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Mrparapluie
Senior Member
Mrparapluie
Joined: 10 Sep 2013
Posts: 19
Location: Quebec
Expertise: I like coffee

Espresso: Gaggia Classic
Grinder: Ascaso iSteel 1 (54 flat...
Posted Tue Jan 14, 2014, 10:05am
Subject: Re: Gaggia classic pre infusion (steam valve open)
 

Thank you Brianl

brianl Said:

Id be careful analyzing your results like that. If you pull the shots back to back, you will get fluxuations in temperature

Posted January 14, 2014 link

I dont pull 10 shot back to back and i carefully wait for the boiler to heating up between the next shot. I have a thermometer install on the boiler to have an idea of what temp is...i know its not the best but help me a lot to know when the temp kick in and when it become to drop.

Thank you Frost

Frost Said:

and it's hard to know what you are doing without a pressure gauge installed.

Posted January 13, 2014 link

Yep i know, my question was to know if somebody else have already try this method and tell me how much bar he get. I will buy a pressure gauge today to test everything.
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D4F
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Joined: 15 Mar 2012
Posts: 2,021
Location: USA
Expertise: I like coffee

Espresso: Gaggia Classic PID
Grinder: Baratza Forte-AP
Posted Tue Jan 14, 2014, 12:49pm
Subject: Re: Gaggia classic pre infusion (steam valve open)
 

calblacksmith Said:

By turning the heater on, you bring your brew temp too high, there is always a new flow of water into the boiler when brewing and the manufacturer took that into account when they designed the machine. By turning the steam switch on, all you are doing is making the water hotter, you are not adding water to the boiler, it is already full of water an it can hold no more.

Posted January 13, 2014 link

To expand a little on this, the aluminum boiler Gaggias are different.  The element is in the boiler wall and not the water.  Many Gaggia users turn on the steam switch for 3 - 4 seconds before and then wait another 3 - 4 seconds before turning on the brew switch.  It does not over heat the water even with a PID and the machine stable.  Cold will water will enter the boiler with the brew switch "on", and have immediate cooling unless you do this.  From steam switch "on" to element heat, to boiler wall heat to heat into the water absorbs that time, and will time heating of the water and cooling of the water to coincide.  That is not accounting for lower flow/pressure while pre-infusing. Of course a thermofilter could be used to time out heat needs with the method described.

The potential difficulty of pre-infusion and use of the steam switch as described without PID is that it removes another method of surfing.  Without PID, some would use the temperature lights to determine and time the brew switch so that brewing starts a little before the boiler heat up is complete and then the cool water in flow will cause the boiler to stay on.  

I did see that OP was using a boiler thermometer and has some idea where the boiler temperature, not the water, is.  I am not sure of the correlation between boiler wall and water temperature in this method.

 
D4F also at
http://www.gaggiausersgroup.com/
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calblacksmith
Moderator
calblacksmith
Joined: 25 Nov 2007
Posts: 7,858
Location: Riverside, Ca, U.S.A.
Expertise: I live coffee

Espresso: ECM Vene. A1, La Cimbali M32
Grinder: Azkoyen Capriccio, Major
Vac Pot: 40s era Silex
Drip: Msl. Com. brewers
Roaster: gave it a try, decided no
Posted Fri Jan 17, 2014, 7:07am
Subject: Re: Gaggia classic pre infusion (steam valve open)
 

For sure, there will be a lag in temp swing as the mass of the boiler shell takes longer to heat than a direct immersion heater does, I suppose that a few seconds would not hurt much but much longer and you are starting to heat the boiler to the steam region, thus my comment about over temp water. YMMV!

 
In real life, my name is
Wayne P.
Anything I post is personal opinion and is only worth as much as anyone else's personal opinion. YMMV!

Feed the newbs, starve the trolls and above all enjoy what you drink!
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