Just got my 1997 Professional in the mail Yesterday (thanks Alan!), I have so far pulled around 18 shots of horrible sour "espresso". I'm using a Columbia that I've roasted so that first crack equals 75-80% of first crack, and tastes rather boring as pour over, I roasted it a week ago Sunday. I also tried a shot of Butundi coffee I roasted 2 days ago with the same toothpaste/orange juice sourness.

I have read a lot of posts trying to get advice, but the advice I've found is vague, or completely contradictory to each other. Everyone states that fresh coffee is a must, but what is fresh? Straight out of the roaster, 2 days, a week???

Some people say to aim for a 30 second pull, others say 15.

I've read that a very fine grind with a very light tamp, and some guy from stumptown says the tamp should be 30 lbs and the lever pull should require 50 lbs...

The dosing amounts I've seen range from 12-18 grams...

One idea I had was to buy a can of Illy to determine if it's my beans...

I put the temp stickers on the group head and it quickly gets to 90c while warming up, and the pressure gets to 1.25 bars after opening the steam wand until steam comes out.

I have tried very fine grinds with both hard and soft Tamps and course ground w/light and hard Tamps and 12-18 gram doses, but all of them taste like sour garbage.

Any advice on what the head temp should optimally be, do I need to reduce the pstat? Thank you!!!

Well I can't answer all your questions, but I might be able to help about the freshness. You can probably find a lot of different opinions about when a roasted coffee is at it's best, bu most agreed that it needs a few days after roasting to de-gas and then it will keep fresh for a couple of weeks. If you buy freshly roasted or roast yourself giving the coffee about 5 days to de-gas should be a safe bet. Perhaps less could do it, but 5 days should ensure that TOO fresh isn't going to be the thing holding you back.
I suspect a lot of the info you find on HB about grinding, dosing and tamping is done on fresh beans, so not so freshly roasted coffee from a can could have some different rules to it. Nothing is certain, but if you feel like you're doing what should work, something other than coffee from a can might be a factor to consider.

Even among people with a expertise, you'll see a wide variety of techniques. You'll need to experiment to find what works best for you. For every new blend you'll want to try pulls hotter, cooler, faster, slower, etc to get it right. Start a few days post roast, and depending on the bean you can easily keep using it for another week or two. (Bishop CA, at 4200ft is not really that high, but there is some opinion that as you get up in elevation the bean peaks at a later post-roast time.)

The can of Illy beans is not a bad idea. Better in my opinion would be an online order from a reputable US roaster - see the roasters listed here: /resources. Or visit some local roasters and taste the espresso there, and take home a bag and see if you can pull a shot at home as good or better than what you were served in the shop.

I tend to pull hard at first and ease off so that the coffee flows out nice and slow through a long (often over 30 secs) pull. But I won't argue with others that favor faster, easier pulls. Is a matter of taste, and depends on the coffee.

I will differ with the advice to put 50 lbs of force on the lever. That would be counterproductive and hard on the machine. 50 lbs of force out near the end of the lever would produce in the neighborhood of 15 bar pressure in the chamber.

Your current pStat setting of 1.25 bar is a bit on the high side. The typical factory setting back when this machine was made was, I believe, at max 0.8 bar.¹ Since you're at 4200 ft elevation, a pStat shutoff setting of 0.95 bar might be justified. (It would give you the same absolute pressure and thus boiler temperature as a sea-level boiler set at 0.8 bar. However, there are conflicting opinions about how to approach pStat settings at altitude.)

Note you don't have to adjust the pStat right away. You can be a human pressurestat, using the on-off switch, toggle it off and let the pressure drop a bit, then experiment pulling at lower boiler pressures. Then based on that you can eventually decide if/where to set your pStat.

You can also cool the group with a cool wet bar towel, and use mini-pumps of the lever to experiment with cooler and with hotter group temps. The group temp is probably the most important thing to understand and master on these machines. This forum has tons of opinion and discussion about that: ( search Pavoni "group temperature" )

[¹] Francesco Ceccarelli's page here says: ".... In practice, many users complain that, having made some coffee, the temperature of the group becomes excessive, the water comes out at a temperature higher than normal and the quality of coffee is unsatisfactory. These reports come directly from users or through the Service Centers, to La Pavoni who initially modifies the calibration of the pressure in an attempt to decrease the operating temperature of the boiler, with reducing the pressure from 0,8-1,0 atm. to 0,5-0.8 (1996)."

I've tried all of the tips on reducing the temp of the brew head, including: the wet towel, cold portafilter, and sucking cool water into the brew head, but even if I do all 3 at the same time I only reduce the temp by 5 degrees and it instantly goes back up.

At lunch today I took the bottom off and loosened the silver screw on the pstat as far as it seemed like I could and the pressure only dropped to 1.1 bars. From what I've found maybe the copper tubing & pstat need to be descaled?

If your shots are sour, you are most likely underextracting, so cooling the grouphead is not your problem. To get a more balanced shot, you need to extract more. So try any combination of the following:

1. Grind finer. (And if necessary down-dose to avoid choking the machine.)
2. Pull hotter. To achieve this on a Pavoni, you can try letting the machine idle for longer before pulling a shot. Using a thermometer attached to the side of the group can help you make these adjustments more predictable. See Gary's "Zen Zone" thread for more details on how to use a thermometer, and the "thermometry" thread to get attachment ideas.
3. Pull longer. Flushing a bit of water through the group can help you reduce "sponginess" and get a higher volume shot.
4. Use beans that have been roasted longer or darker. These will be easier to extract.

Pavoni shots when done right can stand alongside the very best that most machines can make. Just keep playing with the variables, and don't worry too much if it takes a few days to get it right. Make bigger adjustments than you think you should, to find where shots are actually bitter tasting from over-extraction, and then you will know that the sweet spot is somewhere in between those extremes.

Good luck!

What grinder are you using?

I'm using a Lido ET, and I have come close to choking the machine with too fine of a grind.

I'm just guessing, but since the group gets to 210-220f that maybe I can't tell the difference between sour and bitter?

Today at lunch I pulled a decent shot after reducing the pstat to 1.1 bars, and pulling the shot when the group was at 175 f. That was with 15 grams and a very light tamp.

I can try to increase the extraction to see if that's the issue. I'll roast up some darker beans tonight and let em rest for a coupl days.

Does the pstat have a set minimum? Can I screw it up by unscrewing it too far out? I unscrewed it until I felt some resistance and was worried that I may mess things up if I completely unscrewed the set screw.

I suggest starting with:

One shot as the machine warms up from cold - when the group temp rises to about 76C.
11.5 grams of coffee
initial pressure on the lever should be a little less than what would cause the machine to tip forward (with one hand operation). If less than that, grind finer.
30 seconds of extraction time with a constant lever speed (not constant pressure)

Thank you!

Should the espresso need to pour continuously as I pull? I have a Cafelat bottomless portafilter on the way...

Unrooted wrote:Does the pstat have a set minimum? Can I screw it up by unscrewing it too far out? I unscrewed it until I felt some resistance and was worried that I may mess things up if I completely unscrewed the set screw.

Which pStat? Do you see it pictured in this list?
http://www.francescoceccarelli.eu/La_Pa ... to_eng.htm

It's very likely your old pStat just doesn't want to work at low pressures anymore. That's a common failing of the Mater XP-GP ('second model' in that Francesco Ceccarelli list.)