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Monday, June 12, 2006
Home Espresso Machine
The thing about the home espresso machine is that... they just about all suck. With the exception of few double boiler machines, nothing is truly designed for the home environment at all.
All the single boiler machines don't have good temp stability and the "dual-use" boiler is nothing more than a hack.
All the HX(heat exchanger)/E-61 machines are a bastardization of commercial parts into smaller packages (a hack). With a flushing routine (another hack to fix a hack), you can get some temperature stability once it reaches equilibrium. But think about it... how ridiculous is that you have to spend more than a thousand dollar for a piece of equipment that you need to modify and hack to get it to work. The reason for all these hack/mod jobs is that the thing is just not designed right.
Among all the dual boiler machines, Reneka Techno is one of the closest thing to what a properly design home machine is. There is quite a bit of technology that goes into that thing... compact rotary pump, built in pre-infusion, inlet water preheater, vertical boilers, economy mode to turn off steam boilers, brew boiler feed to steam boiler to promote circulation... etc. Unfortuantely, it's too ahead of its time and recieved too little attention here. It would have been real nice to see a updated model in the states.
So looks like a GS/3 it is. I don't know how I am going to get the money, but there is just nothing out there that could do what I want.
ps. I am convinced that all these home users who claimed to have excellent shots from their home machine CONSISTENTLY are either:
1. Using a very "simple" blend that has huge temperature tolerance.
2. Never tasted a properly extracted shot by a skilled barista from a temperature stable commercial machine.
3. Don't have good tastebuds.
- Ben
Related Posts:
Rituale Home Machine Mod stage 1
Rituale Home Machine Mod stage 2
Rituale Home Machine Mod stage 3
Modding the Rituale
Modding the Rituale 2
Modding the Rituale 3
The thing about the home espresso machine is that... they just about all suck. With the exception of few double boiler machines, nothing is truly designed for the home environment at all.
All the single boiler machines don't have good temp stability and the "dual-use" boiler is nothing more than a hack.
All the HX(heat exchanger)/E-61 machines are a bastardization of commercial parts into smaller packages (a hack). With a flushing routine (another hack to fix a hack), you can get some temperature stability once it reaches equilibrium. But think about it... how ridiculous is that you have to spend more than a thousand dollar for a piece of equipment that you need to modify and hack to get it to work. The reason for all these hack/mod jobs is that the thing is just not designed right.
Among all the dual boiler machines, Reneka Techno is one of the closest thing to what a properly design home machine is. There is quite a bit of technology that goes into that thing... compact rotary pump, built in pre-infusion, inlet water preheater, vertical boilers, economy mode to turn off steam boilers, brew boiler feed to steam boiler to promote circulation... etc. Unfortuantely, it's too ahead of its time and recieved too little attention here. It would have been real nice to see a updated model in the states.
So looks like a GS/3 it is. I don't know how I am going to get the money, but there is just nothing out there that could do what I want.
ps. I am convinced that all these home users who claimed to have excellent shots from their home machine CONSISTENTLY are either:
1. Using a very "simple" blend that has huge temperature tolerance.
2. Never tasted a properly extracted shot by a skilled barista from a temperature stable commercial machine.
3. Don't have good tastebuds.
- Ben
Related Posts:
Rituale Home Machine Mod stage 1
Rituale Home Machine Mod stage 2
Rituale Home Machine Mod stage 3
Modding the Rituale
Modding the Rituale 2
Modding the Rituale 3
Labels: rituale mod
¶ Ben Chen 3:36 PM 7 Comments
Wednesday, May 24, 2006
Rituale Transformation Project: Stage 3
So, I could not contain myself and went ahead with the 3rd stage modification. I was able to source a BRAND NEW motor from ebay for $25, and a pump directly from Fluid-o-Tech for $66. With shipping costs and whatever valve/fittings added, the whole setup is only around $120 or so. Quite a deal!!
To keep a "reasonable" pre-infusion, I installed a needle valve downstream of the pump. With it barely crack open, I was able to get down to about 90ml of unrestricted flow in 10 sec. When testing with a blind filter, it takes about 6 seconds to ramp up to full pressure (of 9 bars), which is comparable to the original vibe-pump setup. Interestingly, the pressure with no restriction is now only about 6 bars as opposed to 9 with full restriction.
The pump bypass water @ line pressure from inlet to outlet when not operating, and the vanes do not provide a seal from inlet to outlet. This, in conjuction of keeping my old vibe-pump plumbing (more specifically, the OPV valve), cause water to flow to my drip tray constantly. To remedy this situation, the solenoid from the old direct connect kit was recycled and put on the outlet of the pump. Water is now only allow to flow when the motor turns on.
The pressure drop caused by the constant heating element on/off (due to PID) also went away with the rotary pump conversion. This is the main reason for the upgrade and I am look forward to see what difference it makes.
The machine sounds very differently now when pulling a shot. A bit errie actually with the high pitch whirling of the rotary pump instead of the violent rattle of the vibe that I am used to. I think I will really enjoy the quitness and the steady brew pressure.
[UPDATE 5/26/2006]
OK, I managed to get some free time and finally pulled some shots from the new setup. Either the coffee I am using is getting a bit old (Ecco Daterra Reserve, roasted 5/11), or new rotary pump is really giving that smoothness I been seeking from my home shots. The shots are 1.5 oz double pulled at around 199/200F with a aftermarket ridgeless double (~18g dose). It was loosing a bit of the flavor intensity, but still quite tastey. Most importantly, I was able to capture that silky smoothness I got from LM shots at Simon's that I was never able to reproduce at home. To me, the really steady brew pressure took out all the graininess and rough edges of the shot. I know there were two previous study done by Jim Schulman and Ken Fox that showed no difference between vibe and rotary, but it did made a positive impact on my setup. A totally worthy upgrade! I am excited to try some fresh coffee on the setup to see if I get that clarity in the cup.
-Ben
So, I could not contain myself and went ahead with the 3rd stage modification. I was able to source a BRAND NEW motor from ebay for $25, and a pump directly from Fluid-o-Tech for $66. With shipping costs and whatever valve/fittings added, the whole setup is only around $120 or so. Quite a deal!!
To keep a "reasonable" pre-infusion, I installed a needle valve downstream of the pump. With it barely crack open, I was able to get down to about 90ml of unrestricted flow in 10 sec. When testing with a blind filter, it takes about 6 seconds to ramp up to full pressure (of 9 bars), which is comparable to the original vibe-pump setup. Interestingly, the pressure with no restriction is now only about 6 bars as opposed to 9 with full restriction.
The pump bypass water @ line pressure from inlet to outlet when not operating, and the vanes do not provide a seal from inlet to outlet. This, in conjuction of keeping my old vibe-pump plumbing (more specifically, the OPV valve), cause water to flow to my drip tray constantly. To remedy this situation, the solenoid from the old direct connect kit was recycled and put on the outlet of the pump. Water is now only allow to flow when the motor turns on.
The pressure drop caused by the constant heating element on/off (due to PID) also went away with the rotary pump conversion. This is the main reason for the upgrade and I am look forward to see what difference it makes.
The machine sounds very differently now when pulling a shot. A bit errie actually with the high pitch whirling of the rotary pump instead of the violent rattle of the vibe that I am used to. I think I will really enjoy the quitness and the steady brew pressure.
[UPDATE 5/26/2006]
OK, I managed to get some free time and finally pulled some shots from the new setup. Either the coffee I am using is getting a bit old (Ecco Daterra Reserve, roasted 5/11), or new rotary pump is really giving that smoothness I been seeking from my home shots. The shots are 1.5 oz double pulled at around 199/200F with a aftermarket ridgeless double (~18g dose). It was loosing a bit of the flavor intensity, but still quite tastey. Most importantly, I was able to capture that silky smoothness I got from LM shots at Simon's that I was never able to reproduce at home. To me, the really steady brew pressure took out all the graininess and rough edges of the shot. I know there were two previous study done by Jim Schulman and Ken Fox that showed no difference between vibe and rotary, but it did made a positive impact on my setup. A totally worthy upgrade! I am excited to try some fresh coffee on the setup to see if I get that clarity in the cup.
-Ben
Labels: rituale mod
¶ Ben Chen 9:40 PM 3 Comments
Thursday, May 18, 2006
Rituale Transformation Project: Stage 2 (aka PID in da house!)
Alright, so PID is in. Installation is fairly non-eventful (though not comepletly trouble free), and it only took about 2 to 3 hrs to put in the hardware/wires. The swagelock borethru fitting was a bit pain in the butt to use because it was so small (1/16" OD x 1/4" NPT) and I was a bit worry about the probe hitting one leg of the heating element. But it turn out okay I think. The probe should be about 3/8" to the heating element with about an 3/8" or so of immersion.
Okay, now the hard part. With the PID, I am learning the machine all over again.
I have been taking A LOT of data trying to understand the new behavior and to setup a routine to get what I want. Due to its HX nature, it's a bit more complex than I anticipated. I have to get more data before I can provide an more comprehensive picture. This will take a while (at least a week or two), so don't be surprised if I disappeared for a while again.
One other behavior of the PID - the pump does drop pressure whenever the element comes on (ever 1 sec). This has cemented my idea of getting a rotary pump so part sourcing has begun. I ultimately decided to get an outboard setup to save me money and agony of fitting everything in the case. The parts should be coming in next week or two...
Until then, go drink some espresso. Ecco's Daterra Reserve rules! (Check out their new website! Online order finally!!)
-Ben
Alright, so PID is in. Installation is fairly non-eventful (though not comepletly trouble free), and it only took about 2 to 3 hrs to put in the hardware/wires. The swagelock borethru fitting was a bit pain in the butt to use because it was so small (1/16" OD x 1/4" NPT) and I was a bit worry about the probe hitting one leg of the heating element. But it turn out okay I think. The probe should be about 3/8" to the heating element with about an 3/8" or so of immersion.
Okay, now the hard part. With the PID, I am learning the machine all over again.
I have been taking A LOT of data trying to understand the new behavior and to setup a routine to get what I want. Due to its HX nature, it's a bit more complex than I anticipated. I have to get more data before I can provide an more comprehensive picture. This will take a while (at least a week or two), so don't be surprised if I disappeared for a while again.
One other behavior of the PID - the pump does drop pressure whenever the element comes on (ever 1 sec). This has cemented my idea of getting a rotary pump so part sourcing has begun. I ultimately decided to get an outboard setup to save me money and agony of fitting everything in the case. The parts should be coming in next week or two...
Until then, go drink some espresso. Ecco's Daterra Reserve rules! (Check out their new website! Online order finally!!)
-Ben
Labels: espresso, rituale mod
¶ Ben Chen 11:57 PM 0 Comments
Sunday, May 14, 2006
Rituale Transformation Project: Stage 1
First, a disclaimer about the equipment. The brew water temperature is measured with a K-type thermocouple imbedded between a puck of styrofoam and a puck of sponge stuffed inside a basket. The wire is fished out of a hole on the side of the basket then out to the handle. The limitation of this setup is that, the temperature measured is essentially at the sponge, saturated with brew water. There is a definate delay between actual brew temp and recorded temperature. As a result, the 1st half of the temperature curve is to be used in a qualitative manner. 2nd half of the reading, taken while the prob is soaked in brew water, should accurately reflect the brew temp. Also, I took the measurements at fixed volume flow instead of fix time increments due to the test rig we setup. There is a slight error in this method but I believe it's neglectgible. Anyway, it's the best I can do with what I have. If you want to donate a datalogger or a scace device, feel free to write me an email. Much thanks to Jaime for doing the very boring and tedious datalogging with me. I am sure he is REALLY looking forward to another round of this when the PID goes in, haha.
So here is the summary for the stage 1 of the modification project:
1. The original HX loop is very stable at steady state. The shot has less than 1 degree of variation at the tail end. Shot-to-shot variation seemed to be within 1 degree F.
2. The pre-heater loop seemed to further stablized the temperature. Shot-to-shot variation and overall tail temperature is less than 0.5 degree F (the resolution of my meter).
3. With the Isomac Rituale (1400 watt heater), a recovery time of 2.5 min are required to prevent temperature drop-off at the end of the shot (2 min = 1 degree drop off).
4. The HX configuration can be manipilated with cooling flushes (rebound time of 30 sec) to control the brew temperature (within normal espresso brewing range). The pre-heater loop configuration did not like to be flush too much and require much much longer rebound time.
Conclusion:
1. Looking at the numbers, it seemed that the pre-heater loop configuration sets up the machine very nicely for a sucessful PID job. With tighter broiler temperature control, the brew temperature could be really rock solid.
2. While attempting to adjust the pressurestat to obtain a brewing temperature of 201 F, it was discovered that pressurestats do not really like to be set that low and shot to shot variation became very large. This means that, for normal HX operation, a (large) pre-heater loop is NOT adviced as you could not flush the gouphead to proper temperature with reasonable reovery time.
So, that is it for now. I eagerly awaits the arrival of the thermocouple probe, and hopefully can post further results soon.
- Ben
First, a disclaimer about the equipment. The brew water temperature is measured with a K-type thermocouple imbedded between a puck of styrofoam and a puck of sponge stuffed inside a basket. The wire is fished out of a hole on the side of the basket then out to the handle. The limitation of this setup is that, the temperature measured is essentially at the sponge, saturated with brew water. There is a definate delay between actual brew temp and recorded temperature. As a result, the 1st half of the temperature curve is to be used in a qualitative manner. 2nd half of the reading, taken while the prob is soaked in brew water, should accurately reflect the brew temp. Also, I took the measurements at fixed volume flow instead of fix time increments due to the test rig we setup. There is a slight error in this method but I believe it's neglectgible. Anyway, it's the best I can do with what I have. If you want to donate a datalogger or a scace device, feel free to write me an email. Much thanks to Jaime for doing the very boring and tedious datalogging with me. I am sure he is REALLY looking forward to another round of this when the PID goes in, haha.
So here is the summary for the stage 1 of the modification project:
1. The original HX loop is very stable at steady state. The shot has less than 1 degree of variation at the tail end. Shot-to-shot variation seemed to be within 1 degree F.
2. The pre-heater loop seemed to further stablized the temperature. Shot-to-shot variation and overall tail temperature is less than 0.5 degree F (the resolution of my meter).
3. With the Isomac Rituale (1400 watt heater), a recovery time of 2.5 min are required to prevent temperature drop-off at the end of the shot (2 min = 1 degree drop off).
4. The HX configuration can be manipilated with cooling flushes (rebound time of 30 sec) to control the brew temperature (within normal espresso brewing range). The pre-heater loop configuration did not like to be flush too much and require much much longer rebound time.
Conclusion:
1. Looking at the numbers, it seemed that the pre-heater loop configuration sets up the machine very nicely for a sucessful PID job. With tighter broiler temperature control, the brew temperature could be really rock solid.
2. While attempting to adjust the pressurestat to obtain a brewing temperature of 201 F, it was discovered that pressurestats do not really like to be set that low and shot to shot variation became very large. This means that, for normal HX operation, a (large) pre-heater loop is NOT adviced as you could not flush the gouphead to proper temperature with reasonable reovery time.
So, that is it for now. I eagerly awaits the arrival of the thermocouple probe, and hopefully can post further results soon.
- Ben
Labels: espresso, rituale mod
¶ Ben Chen 12:21 AM 2 Comments
Sunday, May 07, 2006
Day 3?
I am tired... This mod job has taken way more time than I have imagined. In general, I took my time and double/triple check my works. Some mistakes were made, but none are deal breakers. Upon powe up, only 3 leaks were discovered. One at an elbow that I decided to JB-weld it. One at the pressure gauge, which I have re-fitted with some extra teflon tapes. The last leak is at the compression fitting going in the heat exchanger. The tip was cut and a new "bead" was used. Lesson learned - never teflon tape any compression fittings... and make sure you tighten the crap out of it...
The pre-heater loop was a major pain the butt to put in. Bending "soft" copper tubes are not as easy as it seems. I mean, it bends; but if you are not careful, you will "flatten" the tubes. Also, short length and small loops are difficult. The broiler loops are not as tight as I had hope, and only very small parts of each loop is in contact w/ the broiler. This made me worry about it's performance. I put as much insulation as I can all around the broiler/loop. Hopefully this will help its performance a bit. Anyway, what's done is done. I will have to do some measurements to see its performance later this week.
Anyway, I think this finally concludes "Phase 1" of the Rituale Transformation Project, which consists of re-routing all the wires, relocating the controller box, relocating the pump/solenoid assembly, and adding the pre-heating loop (top picture). An machined aluminum braket replaced the orginal internal frame to make room for the relocated pump, which occupied an space alloted for future rotary pump conversion.
Phase 2 of the project will be replacing the current pressurestat with a PID control system. All the parts have been ordered and they should be arriving in the next 2 weeks. Adding these parts should be much easier than phase 1 as all the accomidations for wiring/mounting has been made. It should not take more than an evening worth of work.
If the pre-heater loop + PID works well, I will be looking into replacing the current vibe pump with a rotary pump (phase 3). During my research for the modification project, I have learned that vibe pump is very sensitive to voltage drop. If the heating element comes on while the pump is operating, the output pressure could drop as much as 0.25 bars. This causes the pressure profile to be really jagged and reported to reduce the overall clarity in the cup. Since the PID system will make the heating elements goes on much frequently than the pressurestat, this problem is worsen. However, I hesitate to purchase the pump right away as the miniature version I have spec out is quite expansive (~ $260). If anyone knows another (cheaper) source for the 1/4 HP motor that espresso parts sells, PLEASE contact me and help me save some money!
I am tired... This mod job has taken way more time than I have imagined. In general, I took my time and double/triple check my works. Some mistakes were made, but none are deal breakers. Upon powe up, only 3 leaks were discovered. One at an elbow that I decided to JB-weld it. One at the pressure gauge, which I have re-fitted with some extra teflon tapes. The last leak is at the compression fitting going in the heat exchanger. The tip was cut and a new "bead" was used. Lesson learned - never teflon tape any compression fittings... and make sure you tighten the crap out of it...
The pre-heater loop was a major pain the butt to put in. Bending "soft" copper tubes are not as easy as it seems. I mean, it bends; but if you are not careful, you will "flatten" the tubes. Also, short length and small loops are difficult. The broiler loops are not as tight as I had hope, and only very small parts of each loop is in contact w/ the broiler. This made me worry about it's performance. I put as much insulation as I can all around the broiler/loop. Hopefully this will help its performance a bit. Anyway, what's done is done. I will have to do some measurements to see its performance later this week.
Anyway, I think this finally concludes "Phase 1" of the Rituale Transformation Project, which consists of re-routing all the wires, relocating the controller box, relocating the pump/solenoid assembly, and adding the pre-heating loop (top picture). An machined aluminum braket replaced the orginal internal frame to make room for the relocated pump, which occupied an space alloted for future rotary pump conversion.
Phase 2 of the project will be replacing the current pressurestat with a PID control system. All the parts have been ordered and they should be arriving in the next 2 weeks. Adding these parts should be much easier than phase 1 as all the accomidations for wiring/mounting has been made. It should not take more than an evening worth of work.
If the pre-heater loop + PID works well, I will be looking into replacing the current vibe pump with a rotary pump (phase 3). During my research for the modification project, I have learned that vibe pump is very sensitive to voltage drop. If the heating element comes on while the pump is operating, the output pressure could drop as much as 0.25 bars. This causes the pressure profile to be really jagged and reported to reduce the overall clarity in the cup. Since the PID system will make the heating elements goes on much frequently than the pressurestat, this problem is worsen. However, I hesitate to purchase the pump right away as the miniature version I have spec out is quite expansive (~ $260). If anyone knows another (cheaper) source for the 1/4 HP motor that espresso parts sells, PLEASE contact me and help me save some money!
Labels: espresso, rituale mod
¶ Ben Chen 11:55 PM 4 Comments
Thursday, May 04, 2006
Day 2
Did not have much time today so just some minor work. Start to rewire the system. Routing looks much cleaner so far...
Did not have much time today so just some minor work. Start to rewire the system. Routing looks much cleaner so far...
Labels: espresso, rituale mod
¶ Ben Chen 11:47 PM 0 Comments
Wednesday, May 03, 2006
And the transformation begins
Day one of the tear-down. Unfortunately, I won't be posting much as I will be busying with all the mod stuff. Hopefully the job can be finished by the end of next week so I can enjoy espresso again! Expect a detailed write up once the project is completed. More to come...
Labels: espresso, PID, rituale mod
¶ Ben Chen 6:58 PM 3 Comments