I built a pressure gauge today using a gauge intended for an air compressor.

It leaks a bit as the spout threads weren't exactly 3/8" and I didn't want to over tighten it. But doesn't leak more then a shot being poured.

I ran the machine without the basket and the pressure built and then held steady at 12Bar. I can assume some of the pressure would drop if there was a full shot being poured, but does that seem to high?

Try some teflon tape?

I think I've heard 1.5-2bar drop from water flowing through the puck vs the 0 flow situation, so 9-10 bar is right for a blind basket.

baldheadracing wrote:12 BAR blind is the spec for ESE pod-compatible machines IIRC.

11 bar blind is a good place to be according to the Italians. http://youtu.be/E4y4-E2aL3U

Remember to check the pressure with a fully warmed-up machine (I would guess at least an hour for a Steel Pro.)

The machine was on for a few. I dumped a good amount of water though so wasn't pushing boiling water into the gauge. Would that make any difference?

I did tape the connectors, but I'll add more. Problem is the spout is already a tad too large, can only get one good turn on it.

Would it be worth messing with the pressure valve to decrease flow? I actually thought maybe the pressure was too LOW... so guess that theory of why my shots sucks goes out the window.

ben8jam wrote:I ran the machine without the basket and the pressure built and then held steady at 12Bar. I can assume some of the pressure would drop if there was a full shot being poured, but does that seem to high?

That is likely the factory setting. Makes the machine better able to use ESE pods. I believe the Ascaso steel models with removable portafilter have an OPV. ( http://www.ascaso.com/2012/maquinas-mol ... 2-gran.jpg ) I believe that OPV is adjustable (but not 100% sure.) If you unscrew and remove the barb fitting end I believe you will see a slotted adjuster that can be unscrewed to provide a lower max pressure.

You might benefit by adjusting that pressure down a bit, so that your leaky gauge reads closer to 9 or 10 bar at its max. (if it is leaking at a rate comparable to 60 ml in 30 seconds, then you can go closer to 9 bar.)

Re:

baldheadracing wrote:11 bar blind is a good place to be according to the Italians. http://youtu.be/E4y4-E2aL3U

from the above video: wrote:"In 1930 Mr Achille Gaggia put the first pump on the coffee machine ... he was using a professional pump like this one" (referring to a rotary pump.)

Not sure I believe everything in that video. But his advice to use 11 bar max blind on a vibe pump machine and 9 bar on rotary seems sensible. I use 10 bar (blind) on my vibe pump machine.

Sometimes you need to tweak it a little because it makes a horrible screeching noise at one setting.

I made but found my gauge gets funky with hot water, so you may want to unplug heating element if you can and see if there is a difference. If you get big difference then you may also want to do flow rate test and check it that way. That said, what I did was start at 9 bar, used it for a while, and then turned it up, used it for a while, etc. I will measure when I am done and see what it is, but thinking that I am closer to 11 bar than 9 bar at this point and plan to make just one more small adjustment. So when I am done and it reads 10.5 bars or whatever, it may not actually be 10.5 bar, but I will know its the best setting for how I like it.

HoldTheOnions wrote: So when I am done and it reads 10.5 bars or whatever, it may not actually be 10.5 bar, but I will know its the best setting for how I like it.

Very sensible approach. If you're still new with the machine it's probably a good idea to get used to it, learn to get decent shots on different coffees before bothering to dissemble and tweak that OPV. Then, especially if you like ristretto-ish shots, you can experiment with the lower max pressure.

baldheadracing wrote:I am sure that Bezzera knows that. I presume he was collapsing Gaggia levers with the first pump machines (Faema E61 and all that).

I agree. I think he's Luigi's grandson or great-grandson and should know this history.

HoldTheOnions wrote:That said, what I did was start at 9 bar, used it for a while, and then turned it up, used it for a while, etc. I will measure when I am done and see what it is, but thinking that I am closer to 11 bar than 9 bar at this point and plan to make just one more small adjustment. So when I am done and it reads 10.5 bars or whatever, it may not actually be 10.5 bar, but I will know its the best setting for how I like it.

So I don't want to pull electrical connections just yet, so ran about 600mls of water through before I tested (was still hotish, not sure how it heats up so quickly being a boiler), and tightened everything up so no leaks, and it is a hair above 12bar still.

So, are you saying I should drop the pressure to 9 and work my way up? Or should I just settle at 10.5 - 11. What will running at 12 do to my extractions? I have been having trouble getting good shots. But there are lots of variables still at play and I'm still learning.

(BTW, this only cost $15. $8.50 for the gauge, $4.5 for the 3/8" > 1/4" coupler, and $1.25 for the plumbing tape. Not a bad deal!)

I bought cheap gauge, so for example when cold if it was reading 9 bar, then when hot it would read 8 bar, so a 1 bar difference. I had no idea if it was the gauge or system pressure changing under heat. I tried to ask and it seemed no one else did either, but I believe it was due to the gauge readings changing under heat. Some people want their machine to be 9 bar, period. I mention it because if your gauge is the same and you are trying to achieve a particular pressure, then you may have to account for that difference.

But if you are beginner and don't know what pressure you want, like me, then I recommend starting low and working your way through the range and use it for a little while at each step. To describe the process, if you start low, then you will need a relatively course grind and even a hard tamp will give you watery results with little crema and very sour taste. It will be clearly bad. As you turn it up you will be able to grind finer, the shot will become richer, taste less sour, and give better crema. If the shots start running too fast on a fine grind and tasting bitter, then you have gone too far. Just keep doing this until you are satisfied. You may already know all of this is based upon what you have read, but you won't tangibly understand what it tastes and looks like until you actually do it. At least I didn't.

You will likely be able to make several adjustments the first day just by pulling a few shots at each step. I started at what it said was 9 bar, and it was really bad, but if you start at 9 bar and it ends up being not bad, then I would actually turn it down until is clearly bad and start working up from there. I don't recommend starting somewhere in the good range, because you won't know which way to go from there and I think things will just end up taking longer. As it gets better, it will be harder to judge the difference by only a few shots, so I would then stretch it out at least a few days at each step to get a good feel for it. If you don't have the patience for stretching it out, then you may be able to go straight to pretty good results in one day by simply pulling a ton of shots, but I can't vouch for it. I wasn't in any hurry and I wanted to take the time to experiment with different coffees, grinds, tamps, and doses, so I've been doing it for a few weeks now.