Crema vs. pour time

[barjohn]

Yesterday I was experimenting (I had run out of beans from Vivace's and just received beans from Intelligencia and Sweet Maria's so I figured I needed to recalibrate) and went through almost 1/2 pound of beans trying to figure things out. If I set my grind fineness near the marks on the Mini I get a lot of crema but I get 2 Oz in 15 seconds. I have to increase fineness way up 8-9 notches from the factory setting to slow it down. Tamping pressure held constant and then tried varying tamp pressure (30-50 lbs). Same result. Also, as I increased fineness, crema dropped to about an 1/8" versus 1/2" and puck stays with water on top even when I over fill. It is dry when gorund near factory mark. I think I am grinding way too fine as it feels more like flower than sugar. I have tried two different roasts, Black Cat and Sweet Maria's. Both are fresh roasted within the last few days.

Anyone have any suggestions? Could it be pressure or the new group disk? The wierd thing was that one time I set the grinder back to the factory mark and I got my 2 oz in about 35 sec. So I increased fineness by two notches. It jumped to 4 oz and I could not repeat the earlier result. It has me puzzled. Especially since I took a survey on CG on grinder setting and almost everyone is within 2 notches of factory setting.

[chas]

This is truly curious. I, too, have never had to go more than 2 from factory setting on the Mini. Based on the fact that your grind is like flour and you're still having this problem, it sounds more like the S1 than the grinder.

1) What's your portafilter pressure setting?
2) How long does it take 2oz to pour out of your PF with no coffee loaded?
3) No signs of channeling?
4) Have you removed the screens and diffusion disk to ensure that they're not installed wrong or not seated properly?
5) Any chance water is getting between the basket and the PF thus coming out the spout w/o actually going through the puck?

[barjohn]

1. PF setting is 8.5 bars calibrated reading
2. 7-8 sec.
3. Occasionally but not always.
4. Yes and they are in the factory configuration (not the alternate one)
5. No as the basket lip curves over the edge of the PF.

How does the time compare to your unit? I will double check PF pressure again as I changed water pressure setting recently (down to 20 from 25).

I asked Chris about both pressure gauage kit and drain for drip tray. He said:

"No I can not put a kit together to do what you want. It is a totally
different set up than an Isomac the group is attached directly to the
group boiler. As for a drip try with a drain that is not something la
Spaziale is addressing at this time. There has been little to no
request for it as of yet with 75 machines sold so far.

Chris"

When I pointed out the S1 water circuit and that it could be placed at the pump output I Sent him the message below and his response follows:

"Chris, if you look at the flow diagram Chas put together (which I believe is
correct) you can see that the pressurized output from the pump is fed through the volumetric meter to the group boiler. Since water pressure will be equal everywhere in that circuit a tap anywhere along it would allow a gauge to read the pressure. The easiest point from my inspection is at the output from the pump. The only difficulty is matching threads and fittings and making sure the replacement dual gauge is the same diameter as the original. I would imagine that even John Guest 1/4" tubing could be used from the output of the T. The reason I thought you could offer a kit is that you have access to the plumbing fittings and know the correct sizes. I would have to guess and make multiple trips to my local hardware or Home Depot to get it right. Espresso-Parts offers several dual gauges so I would need to find the one with the right diameter. Again, having your knowledge would be helpful."

Chris's response:

"The guage as you mentioned would have to fit in the existing hole. I have never seen a dual guage that small. John I just don't have time either to be honest with you. I am in the middle of working with other manufacturers in the design and development of some new machines I will be bringing to market in the fall.

Chris"

So I guess if I want it I will have to figure it out myself. Maybe a good weeken project.

[chas]

1. PF setting is 8.5 bars calibrated reading
2. 7-8 sec.
3. Occasionally but not always.
4. Yes and they are in the factory configuration (not the alternate one)
5. No as the basket lip curves over the edge of the PF.

How does the time compare to your unit? I will double check PF pressure again as I changed water pressure setting recently (down to 20 from 25).

I asked Chris about both pressure gauage kit and drain for drip tray. He said:

"No I can not put a kit together to do what you want. It is a totally
different set up than an Isomac the group is attached directly to the
group boiler. As for a drip try with a drain that is not something la
Spaziale is addressing at this time. There has been little to no
request for it as of yet with 75 machines sold so far.

Chris"

When I pointed out the S1 water circuit and that it could be placed at the pump output I Sent him the message below and his response follows:

"Chris, if you look at the flow diagram Chas put together (which I believe is
correct) you can see that the pressurized output from the pump is fed through the volumetric meter to the group boiler. Since water pressure will be equal everywhere in that circuit a tap anywhere along it would allow a gauge to read the pressure. The easiest point from my inspection is at the output from the pump. The only difficulty is matching threads and fittings and making sure the replacement dual gauge is the same diameter as the original. I would imagine that even John Guest 1/4" tubing could be used from the output of the T. The reason I thought you could offer a kit is that you have access to the plumbing fittings and know the correct sizes. I would have to guess and make multiple trips to my local hardware or Home Depot to get it right. Espresso-Parts offers several dual gauges so I would need to find the one with the right diameter. Again, having your knowledge would be helpful."

Chris's response:

"The guage as you mentioned would have to fit in the existing hole. I have never seen a dual guage that small. John I just don't have time either to be honest with you. I am in the middle of working with other manufacturers in the design and development of some new machines I will be bringing to market in the fall.

Chris"

So I guess if I want it I will have to figure it out myself. Maybe a good weeken project.

The expansion valve's not popping open at the 8.5bar and bleeding off water pressure is it?

[barjohn]

Not tha I am aware of. How would that make it run faster? That would slow it down instead due to too little pressure.

By the way, what was your time for 2 oz flow?

Update:
Water Debit is 85-90 Ml in 10 seconds (Just for info)

May have found a possible problem. It seems that I over tightened the nut on the scrrens. This has the effect of permanently deforming the screen and causing water flow to form into one or two streams. I put on my backup screens and only tightend just snug but NOT tight and water flow looks more like a shower. I will test later making some espresso at the 2 notch finer than mark on grinder position and see what happens. (I'm now at 9 notches finer).

If this is right you need to add a warning about how tight to turn screen bolt. I thought it was supposed to be hard snug to minimize grounds getting under the screen. Unfortunately, La Spaziale didn't bother to make these things (screens and dispersion disk) mate in such a way that one could not do what I did.

John

[barjohn]

I tried and it made a small difference but not enough. I will conduct further controlled experiments including trying 14, 15, 16 and 17 gram doses to see if that effects anything. I will also try both increaseing and decreasing pump pressure. Something is off I just am not sure what.

[barjohn]

Here is what I found (1/2 lb) later. Reducing the pressure to 8 bars helped, even 7 bars worked better but I brought it back up to 8 bars. However I found that increasing the amount of grounds in the basket did even more. Filling, tamping, then refilling and tamping to just over the fill ring made the biggest difference as long as I didn't make the pressure too high (9 bars or more). I tried at the high end 10 bars and it was watery, just gushing out. By the way, I am really liking Sweet Maria's Amber Liquid. I prefer it to Black Cat. I also tried using different dispersion disks and screens. I finally wound up with the modified as shown on this web site as the best configuration; however, you really have to fill past the fill ring after tamping for that configuration to work well.

I didn't measure actual grams this go around but now that I am close I will next experiment with actual gram readings to narrow it down further. I wound up with Mini set to 6 notches fines than factory arrow. Still not ideal but 3 notches better than before. I hope this information helps others.

Anyone know what casues the wooshing sound when you first start the process? I think it is air being released via the over pressure valve or the three way but I'm not sure. Especially since one doesn't always get it.

I would think my pressure gauge is reading low except that I checked it against a high precision lab calibrator and I know what the visual readings correspond to on the calibrator.

[chas]

Not tha I am aware of. How would that make it run faster? That would slow it down instead due to too little pressure.

By the way, what was your time for 2 oz flow?

Update:
Water Debit is 85-90 Ml in 10 seconds (Just for info)

May have found a possible problem. It seems that I over tightened the nut on the scrrens. This has the effect of permanently deforming the screen and causing water flow to form into one or two streams. I put on my backup screens and only tightend just snug but NOT tight and water flow looks more like a shower. I will test later making some espresso at the 2 notch finer than mark on grinder position and see what happens. (I'm now at 9 notches finer).

If this is right you need to add a warning about how tight to turn screen bolt. I thought it was supposed to be hard snug to minimize grounds getting under the screen. Unfortunately, La Spaziale didn't bother to make these things (screens and dispersion disk) mate in such a way that one could not do what I did.

John

With an empty basket, I get 2.5oz of water flow in 9 sec which translates to about 1.75oz with coffee loaded in the portafilter.

[barjohn]

2.5 oz is about 90 ml so it seems our water debit is close. After considerably more reading on CG I am convinced that the two biggest factor iare the amount of coffee one puts in the basket (within the physical limitations of the basket of course) and grind fineness. These are followed by the basket design followed by pressure and then temperature. I only rank temperature last because on the S1 temperature is so stable and right on that it is rarely an issue. Pressure is an issue in my mind because unlike a vibe pump where pressure changes with the flow rate, a roary pump maintains constant pressure over a wide flow rate. Thus, too high a pressure will force the liquid through the puck faster. With a vibe pump and an E61 group with pre infusion, first low pressure water is introduced to soak the puck and offer more even resistance to the higher pressure water that follows. Pressure will be highest at the start when resistance to flow is the greatest but will drop as the flow rate increases therefore lengthening the time that the water is in contact with the coffee and the time before blonding occurs. With the rotary, full pressure is amlost available immediately and stays constant throught the pour. Therefore, towards the end the water has little time to leach any more from the grounds. Add more coffee and you increase the time. Reduce the pressure and you increase the time.

All of this theory brings up an interesting point. Has anyone found a source for baskets and if so has anyone tried any other manufacturers basket and what result are you seeing?

Anyone have any other theories? I would love to hear them.

I have added the Procon graph and an Ulka graph from Dan Khen.

[barjohn]

I'm not sure why the images aren't showing. Chas, maybe you can fix.

The URL is http://www.barjohn.com/images the file names are Procon.gif and Vibepump.jpg If I go to the web page they are visible and can be opened.

[chas]

I'm not sure why the images aren't showing. Chas, maybe you can fix.

The URL is http://www.barjohn.com/images the file names are Procon.gif and Vibepump.jpg If I go to the web page they are visible and can be opened.

Capitalization matters on this forum (it's UNIX, not Windows!). The link names you entered into the last post don't match the capitalization of the filenames on your website.

[barjohn]

Thanks, I'll remember that next time. By the way, an interesting aside. The Procon data sheets specified a minimum input water pressure of 20 psi. The graph reflects starting at 20 psi and it being bossted from there.

[bobroseman]

Your last post, John, made me recall that I was a bit surprised when you set your pressure regulator down to 15 psi. I wondered, then, if that was sufficient for the pump but it was just a passing thought. I haven't experienced what you have been describing and my input water pressure is 30 psi. BTW my pressure relief valve doesn't drip at 30 psi except right after a shot.

Regarding coffee quantity, I have been pretty much sticking to 18 grams but small variations don't make much of a difference. Been getting 25-30 seconds for 2 ounces pulls anytime I need to. (Which is to admit that I sometimes get lazy when doing milk drinks )

I experimented with screen tightness and found you could over tighten the screens. But I haven't experienced permanent deformation as you described.

Best wishes,
Bob

[barjohn]

I haven't bothered to do it via gram measurement, using instead the level of the tamped grounds in the basket as my guide. I will try measureing just to see what the results of different diffinitive amounts are, holding everything else constant. By the way, I never went below 20 psi (actually at 22 psi) I was basing the 15 psi on a chapter in Schomer's book on his setup.

[bobroseman]

Dan Kehn taught me to stabilize the coffee weight as one step in making quality shots. I know that there are alternate theories but I can only say that it has worked for me. Give it a try.

Bob

[barjohn]

I have tried various gram weights from 17g to 20g. I have also tried various grind fineness settings.

My results do not make perfect sense. For example, I could not discern any significant difference between 18,5g and 20g, yet when I use a non scientific method I seem to get better results at a coarser grind setting.

I am getting darker coffee longer by just putting in 2.5 full scoops, setting the grinder to about 4 notches finer than factory mark and grinding a batch that just fills basket, doing a quick tamp, re-overfilling basket and smoothing off level and tamping with just ONE gentle tap and final press.

However, the coffee seems a little bitter or so the wife says (I agree). The pour looks much better but still not that perfect pour I see in the video clips.

I will keep trying until I find the right mix. One thing I think I was doing wrong and that is tapping the PF several times to dislodge the coffee from the sides that the tamper pushes up. Schomer says to tap only once and lightly or you will break seal with sides and get the proverbial gusher. I think that was one of my problems as I tended to tap severl times and probably with a little too much vigor.

Just out of curiosity, has anyone been able to get one of those perfect pours where it is black to dark brown and thick like honey for the entire pour? I can get drinkable (with milk) but nothing approaching that yet.

[bobroseman]

John,

Yes, I have been able to do that with coffee that I've bought. My current method of roasting my own has thrown a monkey wrench into my technique. The coffee is so fresh that it tends to either choke the machine or gush out.

Tapping the sides may be causing me problems as well. Why don't we stop tapping on the side altogether. As long as the puck is formed what harm can a few loose grain do on top?

My approach has been to eliminate all variables to the extent possible. I measure out precisely 18 grams because of this. It is just one less variable, that's all. I use a bathroom scale to tamp to between 30 and 40 lbs for the same reason.

I even pull a blank shot into my shot glass to warm it and the portafilter. And I always use a shot glass so that I can measure shot volume exactly.

I shoot for a very thin stream. The thinner the better. I cut off the flow at two ounces or 30 seconds whichever comes first. Two ounces and I increase the finess by an amount determined by the time. 30 seconds and I increase the coursness by an amount determined by the quantity.

The problem with roasting my own is that the pull to pull variation over short periods seems great. I haven't mastered this yet. Frankly, my roasted coffee tastes great as an americano, latte or in a french press but not as espresso.

My feeling is that once you eliminate all the variation that you can, you can better deal with the variation you can't eliminate, ie roast to roast, varietal and relative humidity.

I know that I will not always do it this way. But until I feel that I mastered the technique I will. And it will always give me someplace to go when my shots are turning out bad.

Bob

[barjohn]

Bob, have you found 18g to be the right amount? Did you try more and it didn't work? I ask this because at 18g my basket is only filled to a hair below the fill ring. When I use the other technique it fills to slightly above the fill ring. I haven't tried the dime technique because the head on the screen bolt shows both at 18g and at what is probably closer to 20g. The pour seems better at 20g than at 18g.

I have been trying three different blends, Sweet Maria's, Black Cat and Vivace. Black Cat is a little too oily for me and reminds me of Starbucks in appearance and taste. I like Sweet Maria's but I think I prefer the Vivace to all of them. Sweet Maria's has a bit of a licorice smell and I am not a fan of licorice. Vivace's has more of a good coffee smell and a chocolate taste.

[bobroseman]

John,

2 grams is about 1/14 oz. I doubt that it will make a huge difference in taste but I think that the principle of reducing variables is a good one. 18 or 20, one is 20% over what La Spaziale designed for and the other is 33% over, your choice just stick to it.

As long as your determined not to get sucked into the black hole of coffee roasting, allow me to suggest a roaster that is a bit closer to home (your's, not mine '-) ) blue bottle, order a pound of their Roman Espresso or Espresso Mescal and let me know if Vivace is better. If it is, I'll order some straight away ).

BTW I need some advice but I'm starting a new thread for it.

Bob (On my second martini so forgive the typos)

[bobroseman]

Temescal not Mescal. Blame that second martini. '=)


Bob

[bobroseman]

I just tried omitting the light tamp and coincidently or not, got a 2 oz 25 sec pour with my beans, twice. The third time, it ran about 1.5 oz. Same beans, same grind same tamp. I don't know why.

Bob

[bobroseman]

Just did two more doubles this morning with no tamp and they were great. No gushers and repeatable. 30 second for 2 oz. I think that I've found one of my problems the "light" tamp. Not needed in my view. I think I'll let the coffee geeks tear into it.

Bob

[barjohn]

Bob, that's tap, not tamp! He says that people tend to tap the basket too hard and it breaks the seak between the puck and the sides of the basket and you get a gusher. Do cut back on the "Second" martini!

[bobroseman]

I thought I had replied to this John. Sorry. It is tamp, tap, tamp of course. Those damned "m"s. :D

Interestingly, this week, I've had house guests and the demand for soy lattes has soared to the point where my usual routine just couldn't keep up with the demand, so I have resorted to filling the tamper to heaping and using a sort of diving hand motion to compact the coffee intially, then a tamp, tap, tamp. My guess is that I am using 20 grams by the compacted height in the basket. It is working like a charm and is less trouble than weighing so I will stay with it when my guests leave.

Bob