Don,

Your comment made my day! It is super encouraging to hear.

I think everything we do should be done well so I am glad that my pursuit of that was accomplished

The cup rinser is amazing. I went back and forth in regards to doing a sink or the rinser and I am glad I went with the rinser!

Don Task wrote:Personally, as a craftsman and perfectionist I feel "The beauty of coffee" should also be awarded to one of the most excellent undersink - in cabinet plumbing jobs I've yet to see."

Don,

Your comment made my day! It is super encouraging to hear.

I think everything we do should be done well so I am glad that my pursuit of that was accomplished

The cup rinser is amazing. I went back and forth in regards to doing a sink or the rinser and I am glad I went with the rinser!

Capee7 wrote:I love seeing all of these beautiful setups!!! And to be honest, many of the machines and grinders I saw as I went through these pages were unheard of to me!
......

Emanuel - that's a great setup. Love that rinser! Would you mind letting us know where and the choices you went through? I'm thinking of putting one in a cart for my home setup that I'm thinking about.

Arvista wrote:My COVID project. Since I don't go to the coffee house anymore, I brought the coffee house to me. Just finished setting it up this weekend. Now time to enjoy!!!

Welcome to HB Al! Nice rig!

Thanks a lot! I've made and drank espresso for some 20 years and working from home allowed me to really get into it again. I saw this machine and grinder on Craigslist for a steal (guy closed his restaurant) so I jumped on it. I've learned a lot since getting it, like what a gigleur is, how to strip the hell out of it, and then use a screw extractor to remove and replace it. I also made a great new friend at Voltage Restaurant Supply.

Now it's time to enjoy mass quantities of espresso!

Peppersass wrote:I think Slayer made a smart move switching to the rotary pump. The way the system works, there really is no advantage to having a gear pump, and two disadvantages: less rugged pump and no bypass valve. A rotary pump is more rugged, and the bypass valve protects the pump from the user accidentally closing down the needle valve.

The only reason to have a gear pump for a Slayer shot would be to gradually reduce the speed (and hence the pressure) when the flow speeds up during the back half of the shot, trying to keep a constant flow rate. But the Slayer doesn't offer the ability to dynamically change the pump speed during a shot.

Years ago I replaced the rotary pump in my GS/3 AV with a gear pump so I could do pressure profiling. Recently, I added a "Jake Valve" and a solenoid bypass valve so I can do Slayer shots. I seriously considered going back to the rotary pump, but wanted to retain the ability to dynamically change the pump speed, which I can do with my setup.

Do you currently do both pressure profiling with the gear pump and flow profiling on your GS/3? I recently added the Strada Gear Pump mod to my LMLM and am curious if I could also add the slayer mod to do flow profiling as well.

Yes, I can do both. My typical shot goes as follows:

1. Shot scale tared.
2. Solenoid valve switches in Jake Valve (Jake Valve setting determines flow rate, usually 120ml/min for a Slayer-like shot.)
3. 3-way valve opened and pump started (speed set to 17%-18%, which produces 9 BAR max pressure after basket fills.)
4. After preinfusion time (15-25 seconds), solenoid disengages (bypasses Jake Valve.) Time is usually set to a few seconds past first drops at bottom of basket to ensure that all headspace is filled and pressure has stabilized at max.
5. When flow rate reaches about 25ml/min, gradually reduce gear pump speed to keep flow rate steady and under 30ml/min (for a single -- 60ml/min for a double.)
6. When target shot weight is reached, turn off motor and close 3-way (I can override the scale and turn off the shot if it blonds early.)

Steps 1-4 and 6 are done automatically by an Android tablet connected via Bluetooth to an Acaia Lunar scale and an Arduino microprocessor that interfaces with the GS/3. I do step 5 manually via a speed wheel in the Android tablet interface. It could be done automatically, either in the Android interface or via PID in the Arduino, but it's tricky code, especially since the flow meter in the GS/3 has very low resolution. I like the manual control -- sort of like using a lever. I rarely have enough people to serve that I need to do other things while a shot is running.

[I do step 5 (only) when pulling a traditional (non-Slayer) shot, especially for light and medium roasts. I can also change the ramp time by altering motor speed during preinfusion. I can even set the motor speed to zero and preinfuse at line pressure. These are forms of flow profiling, too, but I don't find they add discernable value. To get the full benefits of long, slow preinfusion, you need to slow the flow rate much further, which is where the Jake Valve comes in.]

Note that you don't necessarily need a gear pump to do flow and pressure profiling. You can use the Jake Valve for both. You would set the Jake valve to produce a low flow rate for preinfusion, then open it fully when stable max pressure is reached, then close it down as the flow rate increases, trying to keep a steady flow rate. It takes some practice to do this, but Jake and others have shown that it can be done. I find the automated solenoid bypass valve and gear pump to be easier to work with, and I already had the gear pump and support electronics/programming in place when I added the Jake Valve and solenoid bypass valve.

Important Note: The gear pump doesn't have a bypass valve. Some models have a safety valve, but it is only for emergencies and not to be used to set operating pressure. This means that the pump can be damaged if the Jake Valve is closed all the way and the expansion valve is not between the pump and the Jake Valve. The stock rotary pump, on the other hand, has a bypass valve and won't care if the Jake Valve is closed all the way.

Capee7 wrote:The beauty of Coffee!

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The beauty of having a built-in glass/portafilter rinser and knock box! Well done.